The effect of Cannabis extract on the morphological and metabolic characteristics of various fat depots in diet-induced Obese and STZ-induced male wistar rats
- Authors: Ramlugon, Sonaal
- Date: 2023-04
- Subjects: Rats as laboratory animals , Diabetes in practice , Cannabis -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61282 , vital:70044
- Description: To investigate the potential anti-diabetic/obesity properties of oral cannabis administration in an obese and streptozotocin (STZ)-induced diabetic rat model, as well as an obese rat model, and to determine the mechanism of action, with a focus on the peritoneal and intramuscular fat depots. Experimental Design: Obese and STZ-induced diabetic rats were allocated a high fat diet (HFD) and intraperitoneally injected with STZ to mimic an obese and diabetic state. The rats were then orally administered cannabis extract (CE) of 1.25, 2.5 and 5.0 mg/kg body weight (relative to tetrahydrocannabinol (THC) content) or metformin as a positive control. For the obese rat model, the rats were allocated either a high carbohydrate diet (HCD) or high fat diet (HFD) and orally administered with cannabis extract of 1.25 mg/kg body weight (relative to THC content). Weight, blood and insulin-resistant parameters of the rats were monitored. The mitochondrial to genomic DNA ratio (MT:18S DNA), average adipocyte area of the various adipose tissues, citrate synthase and carnitine palmitoyltransferase 1 (CPT1) enzyme activities of the peritoneal and intramuscular fat were measured. Gene expression levels of uncoupling protein 1 (UCP1), cell-death inducing DNA fragmentation factor alpha like effector-a (Cidea), perilipin, hormone-sensitive lipase (HSL) and mitochondrial transcription factor A (TFAM) were measured in peritoneal fat, intramuscular fat and brown adipose tissue (BAT). Main Findings: Obese and STZ-induced diabetic rat model: Due to the biphasic nature of cannabinoids, cannabis dosage plays an important role in the observed effects. CE1.25 was the only cannabis treatment effective in improving the insulinresistant parameters of the rats unlike the other higher cannabis concentrations (CE2.5 and CE5.0). In the peritoneal fat, CE1.25 increased MT:18S DNA, increased citrate synthase activity, and decreased the average adipocyte area when compared to the STZ group. CE1.25 also induced fat beigeing by upregulating gene expression levels of UCP1 and Cidea. XIX Furthermore, an increase in gene expression levels of perilipin, HSL, and TFAM showed increased fat mobilization and metabolic activity. In the intramuscular fat, CE1.25 also reduced the average adipocytes area. However, a different mechanism of action was observed where CE1.25 did not induce fat beigeing, but instead increased both citrate synthase and CPT1 enzyme activities and gene expression levels of HSL, thereby indicating increased fat oxidation and mitochondrial activity. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
- Authors: Ramlugon, Sonaal
- Date: 2023-04
- Subjects: Rats as laboratory animals , Diabetes in practice , Cannabis -- South Africa
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10948/61282 , vital:70044
- Description: To investigate the potential anti-diabetic/obesity properties of oral cannabis administration in an obese and streptozotocin (STZ)-induced diabetic rat model, as well as an obese rat model, and to determine the mechanism of action, with a focus on the peritoneal and intramuscular fat depots. Experimental Design: Obese and STZ-induced diabetic rats were allocated a high fat diet (HFD) and intraperitoneally injected with STZ to mimic an obese and diabetic state. The rats were then orally administered cannabis extract (CE) of 1.25, 2.5 and 5.0 mg/kg body weight (relative to tetrahydrocannabinol (THC) content) or metformin as a positive control. For the obese rat model, the rats were allocated either a high carbohydrate diet (HCD) or high fat diet (HFD) and orally administered with cannabis extract of 1.25 mg/kg body weight (relative to THC content). Weight, blood and insulin-resistant parameters of the rats were monitored. The mitochondrial to genomic DNA ratio (MT:18S DNA), average adipocyte area of the various adipose tissues, citrate synthase and carnitine palmitoyltransferase 1 (CPT1) enzyme activities of the peritoneal and intramuscular fat were measured. Gene expression levels of uncoupling protein 1 (UCP1), cell-death inducing DNA fragmentation factor alpha like effector-a (Cidea), perilipin, hormone-sensitive lipase (HSL) and mitochondrial transcription factor A (TFAM) were measured in peritoneal fat, intramuscular fat and brown adipose tissue (BAT). Main Findings: Obese and STZ-induced diabetic rat model: Due to the biphasic nature of cannabinoids, cannabis dosage plays an important role in the observed effects. CE1.25 was the only cannabis treatment effective in improving the insulinresistant parameters of the rats unlike the other higher cannabis concentrations (CE2.5 and CE5.0). In the peritoneal fat, CE1.25 increased MT:18S DNA, increased citrate synthase activity, and decreased the average adipocyte area when compared to the STZ group. CE1.25 also induced fat beigeing by upregulating gene expression levels of UCP1 and Cidea. XIX Furthermore, an increase in gene expression levels of perilipin, HSL, and TFAM showed increased fat mobilization and metabolic activity. In the intramuscular fat, CE1.25 also reduced the average adipocytes area. However, a different mechanism of action was observed where CE1.25 did not induce fat beigeing, but instead increased both citrate synthase and CPT1 enzyme activities and gene expression levels of HSL, thereby indicating increased fat oxidation and mitochondrial activity. , Thesis (PhD) -- Faculty of Science, School of Biomolecular and Chemical Sciences, 2023
- Full Text:
- Date Issued: 2023-04
Histopathological changes in male wistar rats maintained on a water-based sutherlandia frutescens extract
- Authors: Wickens, Nicolas John
- Date: 2012
- Subjects: Rats -- Physiology , Rats as laboratory animals
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4742 , vital:20670
- Description: In this study a standardized 46 week chronic drinking water toxicity protocol was used to elucidate the toxic potential of Sutherlandia frutescens (S. frutescens) using histopathologic, morphometric and transmission electron microscopic analysis. The histopathologic changes in the duodenum, heart, kidney, liver, lung, pancreas and spleen of male Wistar rats were evaluated. Fifty-four rats were randomly divided into four groups: Group 1 – Normal diet control (ND control), n=7, Group 2 – Normal diet + plant extract (ND + p), n=9, Group 3 – High fat diet control (HFD control), n=19Group 4 – High fat diet + p (HFD + p), n=19In the high fat group male Wistar rats were fed ±55 g/day of a specialised high fat diet over a 46 week period to induce obesity and an insulin resistant state. The treatment groups (groups 2 and 4) received a dose concentration of a tea extract of the S. frutescens plant in their drinking water daily. This study showed that the consumption of S. frutescens significantly reduces weight gain in male Wistar rats on a chronic high fat diet (p≤0.001 vs. HFD control group). S. frutescens appears to propagate periportal and centrilobular glycogen storage in rat hepatocytes in the experimental groups as exemplified by a significantly (p≤0.0001 vs. control groups) increased incidences of Periodic Acid Schiff (PAS) positive staining S. frutescens also reduced intracellular lipid accumulation as made evident by the significantly lower incidence of epicardial adipose tissue (EAT), hepatic steatosis and pancreatic interstitial fat. Obesity was associated with increased fibrotic lesions such as myocardial perivascular fibrosis, centrilobular hepatic fibrosis and pancreatic periductal fibrosis. Obesity associated hypertension contributed to the widespread and significant increase in the average lesion severity of arterial congestion in all organs in the HFD control group. Pulmonary infection was equally prevalent in all rats. Despite the complex histopathology in all groups, differences in the control groups, such as, the presence of a conservative polymorphonuclear leukocyte (PMNL) infiltration, substantial intra-alveolar oedema and focal arterial wall hypertrophy in the control groups was highly suggestive of Sendai viral infection. However histopathologic evidence, in the treatment groups, suggested chronic recurrent viral infection with superimposed Mycoplasma pulmonis (M. pulmonis) bacterial infection. The impact of advanced suppurative pulmonary infection was widespread and exemplified by increased lesion incidences of spontaneous murine progressive cardiomyopathy (MCP) and spontaneous chronic progressive nephropathy (CPN) among others. In conclusion S. frutescens administered for 46 weeks to male Wistar rats significantly lowered intracellular lipid accumulation and obesity associated myocardial, renal, hepatobiliary, pulmonary and pancreatic histopathology. Moreover, duodenal, cardiovascular, hepatobiliary, pulmonary, renal, pancreatic and splenic tissue did not show histopathologic evidence of direct plant extract associated toxicity or carcinogenicity.
- Full Text:
- Date Issued: 2012
- Authors: Wickens, Nicolas John
- Date: 2012
- Subjects: Rats -- Physiology , Rats as laboratory animals
- Language: English
- Type: Thesis , Doctoral , DTech
- Identifier: http://hdl.handle.net/10948/4742 , vital:20670
- Description: In this study a standardized 46 week chronic drinking water toxicity protocol was used to elucidate the toxic potential of Sutherlandia frutescens (S. frutescens) using histopathologic, morphometric and transmission electron microscopic analysis. The histopathologic changes in the duodenum, heart, kidney, liver, lung, pancreas and spleen of male Wistar rats were evaluated. Fifty-four rats were randomly divided into four groups: Group 1 – Normal diet control (ND control), n=7, Group 2 – Normal diet + plant extract (ND + p), n=9, Group 3 – High fat diet control (HFD control), n=19Group 4 – High fat diet + p (HFD + p), n=19In the high fat group male Wistar rats were fed ±55 g/day of a specialised high fat diet over a 46 week period to induce obesity and an insulin resistant state. The treatment groups (groups 2 and 4) received a dose concentration of a tea extract of the S. frutescens plant in their drinking water daily. This study showed that the consumption of S. frutescens significantly reduces weight gain in male Wistar rats on a chronic high fat diet (p≤0.001 vs. HFD control group). S. frutescens appears to propagate periportal and centrilobular glycogen storage in rat hepatocytes in the experimental groups as exemplified by a significantly (p≤0.0001 vs. control groups) increased incidences of Periodic Acid Schiff (PAS) positive staining S. frutescens also reduced intracellular lipid accumulation as made evident by the significantly lower incidence of epicardial adipose tissue (EAT), hepatic steatosis and pancreatic interstitial fat. Obesity was associated with increased fibrotic lesions such as myocardial perivascular fibrosis, centrilobular hepatic fibrosis and pancreatic periductal fibrosis. Obesity associated hypertension contributed to the widespread and significant increase in the average lesion severity of arterial congestion in all organs in the HFD control group. Pulmonary infection was equally prevalent in all rats. Despite the complex histopathology in all groups, differences in the control groups, such as, the presence of a conservative polymorphonuclear leukocyte (PMNL) infiltration, substantial intra-alveolar oedema and focal arterial wall hypertrophy in the control groups was highly suggestive of Sendai viral infection. However histopathologic evidence, in the treatment groups, suggested chronic recurrent viral infection with superimposed Mycoplasma pulmonis (M. pulmonis) bacterial infection. The impact of advanced suppurative pulmonary infection was widespread and exemplified by increased lesion incidences of spontaneous murine progressive cardiomyopathy (MCP) and spontaneous chronic progressive nephropathy (CPN) among others. In conclusion S. frutescens administered for 46 weeks to male Wistar rats significantly lowered intracellular lipid accumulation and obesity associated myocardial, renal, hepatobiliary, pulmonary and pancreatic histopathology. Moreover, duodenal, cardiovascular, hepatobiliary, pulmonary, renal, pancreatic and splenic tissue did not show histopathologic evidence of direct plant extract associated toxicity or carcinogenicity.
- Full Text:
- Date Issued: 2012
Observed pathological changes in male Wistar rats after co-treatment of Type II Diabetes with metformin and sutherlandia frutescens
- Authors: Tili, Siphokazi Pamphilia
- Date: 2012
- Subjects: Rats -- Physiology , Rats as laboratory animals , Non-insulin-dependent diabetes -- Research
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10123 , http://hdl.handle.net/10948/d1012644 , Rats -- Physiology , Rats as laboratory animals , Non-insulin-dependent diabetes -- Research
- Description: Diabetes is a serious condition that affects all the body’s systems including kidneys, heart, eyes and limbs. This alone makes type II diabetes a life threatening disease; an expensive disease and economic burden that many individuals struggle to cope with.The rapid growth type II diabetes in South Africa is associated with the change of life style, and environmental factors brought by westernized way of life living in rural areas. Despite the technical advances in diagnosis and therapy of diabetes many people still use alternative forms of therapy due to the cost, traditional reasons and religion. Some of the people use the conventional medication together with the alternative therapy without informing their doctor and knowing the pathological changes. The aim of the study was to investigate pathological changes in male Wistar rats after co-treatment of type II diabetes with metformin and Sutherlandia frutescens and the possible synergistic and antagonistic effects. The thirty five rats were divided into five groups, seven in each group. There were two control groups and three test groups. Only the first control group was on a low fat diet (normal rat pellets) and second control group and test groups were on a high fat diet which induces obesity, insulin resistance and leads a typical prediabetic state for 12 weeks (Buettner et al., 2006). After 11.5 weeks medication was administered by oral gavaging to the test groups for 4 weeks and control groups received water. Blood was collected for determination of glucose, insulin, lipid profile and the concentrations of the liver enzymes. Pancreas, liver and kidney tissue were removed and used for histology. Urine was collected from the bladder for creatinine analyses. The plant + metformin group co-treatment was better in managing hyperglycemia, liver damages were minimal and also weight control was better when compared to metformin alone.
- Full Text:
- Date Issued: 2012
- Authors: Tili, Siphokazi Pamphilia
- Date: 2012
- Subjects: Rats -- Physiology , Rats as laboratory animals , Non-insulin-dependent diabetes -- Research
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10123 , http://hdl.handle.net/10948/d1012644 , Rats -- Physiology , Rats as laboratory animals , Non-insulin-dependent diabetes -- Research
- Description: Diabetes is a serious condition that affects all the body’s systems including kidneys, heart, eyes and limbs. This alone makes type II diabetes a life threatening disease; an expensive disease and economic burden that many individuals struggle to cope with.The rapid growth type II diabetes in South Africa is associated with the change of life style, and environmental factors brought by westernized way of life living in rural areas. Despite the technical advances in diagnosis and therapy of diabetes many people still use alternative forms of therapy due to the cost, traditional reasons and religion. Some of the people use the conventional medication together with the alternative therapy without informing their doctor and knowing the pathological changes. The aim of the study was to investigate pathological changes in male Wistar rats after co-treatment of type II diabetes with metformin and Sutherlandia frutescens and the possible synergistic and antagonistic effects. The thirty five rats were divided into five groups, seven in each group. There were two control groups and three test groups. Only the first control group was on a low fat diet (normal rat pellets) and second control group and test groups were on a high fat diet which induces obesity, insulin resistance and leads a typical prediabetic state for 12 weeks (Buettner et al., 2006). After 11.5 weeks medication was administered by oral gavaging to the test groups for 4 weeks and control groups received water. Blood was collected for determination of glucose, insulin, lipid profile and the concentrations of the liver enzymes. Pancreas, liver and kidney tissue were removed and used for histology. Urine was collected from the bladder for creatinine analyses. The plant + metformin group co-treatment was better in managing hyperglycemia, liver damages were minimal and also weight control was better when compared to metformin alone.
- Full Text:
- Date Issued: 2012
Effect of a South African medicinal plant on antiretroviral drug induced abnormalities in rats
- Authors: Van Gend, Tania Anli
- Date: 2008
- Subjects: Medicinal plants -- South Africa , Antiretroviral agents -- South Africa , Materia medica, Vegetable -- South Africa , HIV infections -- Alternative treatment -- South Africa , Rats as laboratory animals , Rats -- Metabolism
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10121 , http://hdl.handle.net/10948/1080 , Medicinal plants -- South Africa , Antiretroviral agents -- South Africa , Materia medica, Vegetable -- South Africa , HIV infections -- Alternative treatment -- South Africa , Rats as laboratory animals , Rats -- Metabolism
- Description: The worldwide AIDS epidemic is known to have had a profoundly negative social, economic and personal impact and has taken a heavy toll on existing health care systems, particularly in developing countries. South Africa is experiencing an HIV epidemic with enormous social and economic consequences. Lopinavir/ritonavir antiretroviral treatment has been accredited with having a significantly positive effect and is a key advance in controlling HIV morbidity and mortality. An indigenous South African medicinal plant, Sutherlandia frutescens, known for its anti-diabetic properties and immune-boosting effects, is used for treating HIV positive patients suffering from opportunistic infections. Despite the use of the medicinal plant extract as homeotherapeutic medication, there is little evidence of toxicity testing that identifies its potential for interaction with antiretroviral drugs. However, scientific data relating to the mechanism through which Sutherlandia frutescens acts on the immune system has not been comprehensively documented. The aim of this study was to investigate lopinavir/ritonavir induced metabolic abnormalities in rats and whether the introduction of a plant extract of Sutherlandia frutescens would counteract the side effects of ARV medication. The results indicated that the rodents did not become insulin resistant, however, biochemical analysis indicated that extended ARV drug treatment would have caused insulin resistance. Significant morphological changes were found in the livers, kidneys and pancreases of rats exposed to the lopinavir/ritonavir. Rats exposed to the Sutherlandia frutescens plant extract showed improved histopathology with minimal abnormalities.
- Full Text:
- Date Issued: 2008
- Authors: Van Gend, Tania Anli
- Date: 2008
- Subjects: Medicinal plants -- South Africa , Antiretroviral agents -- South Africa , Materia medica, Vegetable -- South Africa , HIV infections -- Alternative treatment -- South Africa , Rats as laboratory animals , Rats -- Metabolism
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10121 , http://hdl.handle.net/10948/1080 , Medicinal plants -- South Africa , Antiretroviral agents -- South Africa , Materia medica, Vegetable -- South Africa , HIV infections -- Alternative treatment -- South Africa , Rats as laboratory animals , Rats -- Metabolism
- Description: The worldwide AIDS epidemic is known to have had a profoundly negative social, economic and personal impact and has taken a heavy toll on existing health care systems, particularly in developing countries. South Africa is experiencing an HIV epidemic with enormous social and economic consequences. Lopinavir/ritonavir antiretroviral treatment has been accredited with having a significantly positive effect and is a key advance in controlling HIV morbidity and mortality. An indigenous South African medicinal plant, Sutherlandia frutescens, known for its anti-diabetic properties and immune-boosting effects, is used for treating HIV positive patients suffering from opportunistic infections. Despite the use of the medicinal plant extract as homeotherapeutic medication, there is little evidence of toxicity testing that identifies its potential for interaction with antiretroviral drugs. However, scientific data relating to the mechanism through which Sutherlandia frutescens acts on the immune system has not been comprehensively documented. The aim of this study was to investigate lopinavir/ritonavir induced metabolic abnormalities in rats and whether the introduction of a plant extract of Sutherlandia frutescens would counteract the side effects of ARV medication. The results indicated that the rodents did not become insulin resistant, however, biochemical analysis indicated that extended ARV drug treatment would have caused insulin resistance. Significant morphological changes were found in the livers, kidneys and pancreases of rats exposed to the lopinavir/ritonavir. Rats exposed to the Sutherlandia frutescens plant extract showed improved histopathology with minimal abnormalities.
- Full Text:
- Date Issued: 2008
Observed metabolic changes in male Wistar rats after treatment with an antidepressant implied in undesirable weight gain, or Sutherlandia frutescens for Type II diabetes
- Authors: Chadwick, Wayne
- Date: 2003
- Subjects: Rats -- Metabolism , Non-insulin-dependent diabetes -- Research , Rats as laboratory animals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11068 , http://hdl.handle.net/10948/313 , Rats -- Metabolism , Non-insulin-dependent diabetes -- Research , Rats as laboratory animals
- Description: Type II diabetes is fast becoming a growing problem in developed countries worldwide. Traditionally the median age for diagnosis was around sixty, but recent surveys have shown that the entire age distribution curve has shifted to the left. Western countries boast the worst statistics in which type II diabetes is being reported in children under the age of ten. At such a young age the disease often goes undiagnosed for long periods of time allowing considerable damage to occur. The incidence of type II diabetes is thought to be parallel with the growing rate of obesity associated with a characteristically unhealthy western diet. Type II diabetes is an extremely expensive disease to manage, and with the rapid growth of this pandemic our country will soon feel the economic burden of this disease. It is for this reason that cheaper medication needs to be investigated in the form of traditional plants, such as Sutherlandia frutescens. Prescription medication, such as tricyclic antidepressants, may also increase body weight or appetite thereby playing a role in obesity. The cause of weight gain in such cases may go unrecognized or lead to cessation of the medication with or without the practitioner’s knowledge or approval. It is therefore necessary to investigate the causative agents responsible for the excessive weight gain. Drinking water containing extracts of the S. frutescens, metformin (a well known type II diabetes medication) and amitriptyline (a common tricyclic antidepressant) was administered to three groups of ten male Wistar rats. The control group received water without any medication. The rat’s weight and food consumption was monitored throughout the trial and their oxygen consumption was also determined. Rats were sacrificed after four months of medicinal compliance and glucose uptake, in the presence and absence of insulin, was tested in epididymal fat, liver and muscle. Fasting plasma glucose levels, lipoprotein, cholesterol and triglyceride concentrations were also determined.
- Full Text:
- Date Issued: 2003
- Authors: Chadwick, Wayne
- Date: 2003
- Subjects: Rats -- Metabolism , Non-insulin-dependent diabetes -- Research , Rats as laboratory animals
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:11068 , http://hdl.handle.net/10948/313 , Rats -- Metabolism , Non-insulin-dependent diabetes -- Research , Rats as laboratory animals
- Description: Type II diabetes is fast becoming a growing problem in developed countries worldwide. Traditionally the median age for diagnosis was around sixty, but recent surveys have shown that the entire age distribution curve has shifted to the left. Western countries boast the worst statistics in which type II diabetes is being reported in children under the age of ten. At such a young age the disease often goes undiagnosed for long periods of time allowing considerable damage to occur. The incidence of type II diabetes is thought to be parallel with the growing rate of obesity associated with a characteristically unhealthy western diet. Type II diabetes is an extremely expensive disease to manage, and with the rapid growth of this pandemic our country will soon feel the economic burden of this disease. It is for this reason that cheaper medication needs to be investigated in the form of traditional plants, such as Sutherlandia frutescens. Prescription medication, such as tricyclic antidepressants, may also increase body weight or appetite thereby playing a role in obesity. The cause of weight gain in such cases may go unrecognized or lead to cessation of the medication with or without the practitioner’s knowledge or approval. It is therefore necessary to investigate the causative agents responsible for the excessive weight gain. Drinking water containing extracts of the S. frutescens, metformin (a well known type II diabetes medication) and amitriptyline (a common tricyclic antidepressant) was administered to three groups of ten male Wistar rats. The control group received water without any medication. The rat’s weight and food consumption was monitored throughout the trial and their oxygen consumption was also determined. Rats were sacrificed after four months of medicinal compliance and glucose uptake, in the presence and absence of insulin, was tested in epididymal fat, liver and muscle. Fasting plasma glucose levels, lipoprotein, cholesterol and triglyceride concentrations were also determined.
- Full Text:
- Date Issued: 2003
The effects of melatonin on the testis, epididymis and sperm physiology of the Wistar rat
- Authors: Gwayi, Noluzuko
- Date: 2001
- Subjects: Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5681 , http://hdl.handle.net/10962/d1005366 , Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Description: Melatonin is a product of the pineal gland and is postulated to play an antigonadotropic role in the reproductive system of mammals. The reproductive system of non-seasonally breeding mammals is believed to be not as responsive to melatonin treatment as that of seasonally breeding mammals. Recently, there has been increasing support from in vivo and in vitro studies, for the hypothesis that melatonin has negative effects on sperm physiology, especially on sperm motility. High and/or low seminal concentrations of melatonin have been associated with abnormalities in human sperm motility and concentration. In this study, I examined the effects of melatonin on the testis, epididymis and sperm physiology, using in vivo and in vitro experiments, in a non-seasonally breeding mammal. Treatment, in vivo, with exogenous melatonin for six weeks did not inhibit testosterone production or spermatogenesis, nor did it affect the mass of the testes and epididymides at dissection, the concentration the morphology of speimatozoa. However, melatonin in vivo had a small, but significant negative effect on sperm motility and sperm motility index. In vitro incubation of spermatozoa Fith melatonin reduced the percentage (%) of forward progressive movement (fpm), increased the % reduction in fpm, reduced the vigor or quality of sperm motility, reduced the sperm motility index, and delayed and/or prolonged the transition of one pattern of sperm motility to the subsequent patterns. Melatonin increased the pH of the culture medium, and the increased pH, and the ethanol utilized as a solvent for melatonin, both negatively affected all the sperm motility parameters that were assessed in my study. The effects of ethanol increased with time, and the effects of pH increased with both time and increasing pH. Melatonin in vitro did not inhibit capacitation and the acrosome reaction, but it delayed the onset and the progression of capacitation and the acrosome reaction. These results suggest that while melatonin did not inhibit spermatogenesis in the Wistar rat, it may influence sperm motility. Therefore, the presence of high concentrations of melatonin in the reproductive fluids may inhibit sperm motility. With further detailed research, melatonin may have a potential use as a contraceptive drug.
- Full Text:
- Date Issued: 2001
- Authors: Gwayi, Noluzuko
- Date: 2001
- Subjects: Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5681 , http://hdl.handle.net/10962/d1005366 , Rats as laboratory animals , Rats -- physiology , Spermatozoa , Melatonin , Testis , Epididymis
- Description: Melatonin is a product of the pineal gland and is postulated to play an antigonadotropic role in the reproductive system of mammals. The reproductive system of non-seasonally breeding mammals is believed to be not as responsive to melatonin treatment as that of seasonally breeding mammals. Recently, there has been increasing support from in vivo and in vitro studies, for the hypothesis that melatonin has negative effects on sperm physiology, especially on sperm motility. High and/or low seminal concentrations of melatonin have been associated with abnormalities in human sperm motility and concentration. In this study, I examined the effects of melatonin on the testis, epididymis and sperm physiology, using in vivo and in vitro experiments, in a non-seasonally breeding mammal. Treatment, in vivo, with exogenous melatonin for six weeks did not inhibit testosterone production or spermatogenesis, nor did it affect the mass of the testes and epididymides at dissection, the concentration the morphology of speimatozoa. However, melatonin in vivo had a small, but significant negative effect on sperm motility and sperm motility index. In vitro incubation of spermatozoa Fith melatonin reduced the percentage (%) of forward progressive movement (fpm), increased the % reduction in fpm, reduced the vigor or quality of sperm motility, reduced the sperm motility index, and delayed and/or prolonged the transition of one pattern of sperm motility to the subsequent patterns. Melatonin increased the pH of the culture medium, and the increased pH, and the ethanol utilized as a solvent for melatonin, both negatively affected all the sperm motility parameters that were assessed in my study. The effects of ethanol increased with time, and the effects of pH increased with both time and increasing pH. Melatonin in vitro did not inhibit capacitation and the acrosome reaction, but it delayed the onset and the progression of capacitation and the acrosome reaction. These results suggest that while melatonin did not inhibit spermatogenesis in the Wistar rat, it may influence sperm motility. Therefore, the presence of high concentrations of melatonin in the reproductive fluids may inhibit sperm motility. With further detailed research, melatonin may have a potential use as a contraceptive drug.
- Full Text:
- Date Issued: 2001
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