The present study was carried out to investigate the acute effect of aspartame on oxidative stress in the Wistar albino rat brain. We sought to investigate whether acute administration of aspartame （75 mg/kg） could ...The present study was carried out to investigate the acute effect of aspartame on oxidative stress in the Wistar albino rat brain. We sought to investigate whether acute administration of aspartame （75 mg/kg） could release methanol and induce oxidative stress in the rat brain 24 hours after administration. To mimic human methanol metabolism, methotrexate treated rats were used to study aspartame effects. Wistar strain male albino rats were administered with aspartame orally as a single dose and studied along with controls and methotrexate treated controls. Blood methanol and formate level were estimated after 24 hours and rats were sacrificed and free radical changes were observed in discrete regions by assessing the scavenging enzymes, reduce dglutathione （GSH）, lipid peroxidation and protein thiol levels. There was a significant increase in lipid peroxidation levels, superoxide dismutase activity （SOD）, glutathione peroxidase levels （GPx）, and catalase activity （CAT） with a significant decrease in GSH and protein thiol. Aspartame exposure resulted in detectable methanol even after 24 hours. Methanol and its metabolites may be responsible for the generation of oxidative stress in brain regions. The observed alteration in aspartame fed animals may be due to its metabolite methanol and elevated formate. The elevated free radicals due to methanol induced oxidative stress.展开更多
Noise has been regarded as an environmental/occupational stressor that causes damages to both auditory and non- auditory organs. Prolonged exposure to these mediators of stress has often resulted in detrimental effect...Noise has been regarded as an environmental/occupational stressor that causes damages to both auditory and non- auditory organs. Prolonged exposure to these mediators of stress has often resulted in detrimental effect, where oxidative/nitrosative stress plays a major role. Hence, it would be appropriate to examine the possible role of free radicals in brain discrete regions and the ＂antioxidants＂ mediated response of S. dulcis. Animals were subjected to noise stress for 15 days （100 dB/4 hours/day） and estimation of endogenous free radical and antioxidant activity were carried out on brain discrete regions （the cerebral cortex, cerebellum, brainstem, striatum, hippocampus and hypothalamus）. The result showed that exposure to noise could alleviate endogenous free radical generation and altered anfioxidant status in brain discrete regions when compared to that of the control groups. This alleviated free radical generation （H202 and NO） is well supported by an upregulated protein expression on immunohistochemistry of both iNOS and nNOS in the cerebral cortex on exposure to noise stress. These findings suggest that increased free radical generation and altered anti-oxidative status can cause redox imbalance in the brain discrete regions~ However, free radical scavenging activity of the plant was evident as the noise exposed group treated with S. dulcis[200 mg/（kg · b. w）] displayed a therapeutic effect by decreasing the free radical level and regulate the anti-oxidative status to that of control animals. Hence, it can be concluded that the efficacy of S. dulcis could be attributed to its free radical scavenging activity and anti-oxidative property.展开更多
基金financial assistance was provided by the University of Madras
文摘The present study was carried out to investigate the acute effect of aspartame on oxidative stress in the Wistar albino rat brain. We sought to investigate whether acute administration of aspartame （75 mg/kg） could release methanol and induce oxidative stress in the rat brain 24 hours after administration. To mimic human methanol metabolism, methotrexate treated rats were used to study aspartame effects. Wistar strain male albino rats were administered with aspartame orally as a single dose and studied along with controls and methotrexate treated controls. Blood methanol and formate level were estimated after 24 hours and rats were sacrificed and free radical changes were observed in discrete regions by assessing the scavenging enzymes, reduce dglutathione （GSH）, lipid peroxidation and protein thiol levels. There was a significant increase in lipid peroxidation levels, superoxide dismutase activity （SOD）, glutathione peroxidase levels （GPx）, and catalase activity （CAT） with a significant decrease in GSH and protein thiol. Aspartame exposure resulted in detectable methanol even after 24 hours. Methanol and its metabolites may be responsible for the generation of oxidative stress in brain regions. The observed alteration in aspartame fed animals may be due to its metabolite methanol and elevated formate. The elevated free radicals due to methanol induced oxidative stress.
基金provided by the University Grants Commission-RGNF(SC/ST)
文摘Noise has been regarded as an environmental/occupational stressor that causes damages to both auditory and non- auditory organs. Prolonged exposure to these mediators of stress has often resulted in detrimental effect, where oxidative/nitrosative stress plays a major role. Hence, it would be appropriate to examine the possible role of free radicals in brain discrete regions and the ＂antioxidants＂ mediated response of S. dulcis. Animals were subjected to noise stress for 15 days （100 dB/4 hours/day） and estimation of endogenous free radical and antioxidant activity were carried out on brain discrete regions （the cerebral cortex, cerebellum, brainstem, striatum, hippocampus and hypothalamus）. The result showed that exposure to noise could alleviate endogenous free radical generation and altered anfioxidant status in brain discrete regions when compared to that of the control groups. This alleviated free radical generation （H202 and NO） is well supported by an upregulated protein expression on immunohistochemistry of both iNOS and nNOS in the cerebral cortex on exposure to noise stress. These findings suggest that increased free radical generation and altered anti-oxidative status can cause redox imbalance in the brain discrete regions~ However, free radical scavenging activity of the plant was evident as the noise exposed group treated with S. dulcis[200 mg/（kg · b. w）] displayed a therapeutic effect by decreasing the free radical level and regulate the anti-oxidative status to that of control animals. Hence, it can be concluded that the efficacy of S. dulcis could be attributed to its free radical scavenging activity and anti-oxidative property.
