Effects of Co-administration of Methamphetamine and Vitamin E on the Hippocampus of Adult Male Wistar Rats

Abstract

Much attention has been given to the toxic effects of methamphetamine on humans. However, it is not clear whether this toxicity is related to vital organs such as the hippocampus; hence, the present study aimed not only to elucidate the toxic effect of methamphetamine (METH) on the hippocampus but also, more importantly, to investigate the protective effect of vitamin E against methamphetamine-induced toxicity in this organ. Thirty-five adult Wistar rats (185-220g) were divided into seven groups of five animals each. Group A was given normal rat feed and water as the control; groups B, C, D, E, F, and G, were administered 5 mg/kg body weight of METH, 10 mg/kg body weight of METH, 500 mg/kg body weight of vitamin E, 1000 mg/kg body weight of vitamin E, 5 mg/kg body weight of METH and 500 mg/kg body weight of vitamin E, and 10 mg/kg body weight of METH and 1000mg/kg body weight of vitamin E, respectively. All the treatments were administered orally daily for twenty-one, Neurobehavioral test was conducted three days before the last administration. days; 24 hours after the last exposure, the animals were anesthetized using chloroform vapour. The brain tissues were harvested, and weighed, and some of the tissues were fixed in phosphate buffered formalin for biochemical analysis, while the rest were fixed in 10% neutral buffer formalin for histological studies. Compared with those in the control group, the body weights of the animals in groups B, C, F and G, which were administered methamphetamine, were significantly lower. The serum levels of malondialdehyde (MAD) in groups B, C, F & G were significantly greater (P<0.05) than those in the control group, whereas the serum levels of gluthathione (GSH); and superoxide dismutase (SOD) in groups B & C (P>0.05) were significantly lower than those in the control group. Histological observations revealed that following the administration of vitamin E, there were no degenerated cells; instead, there was an increase in the number of active granular cells in groups A, D & E, and mild regeneration, moderate /-mild vacuolation and a moderate increase in the number of active granular cells were observed in groups F & G, whereas severe degeneration and vacuolation and severe pyknotic granular cells were observed in groups B & C. The results of this study revealed that no adverse biochemical alterations were associated with the use of vitamin E and no histopathological lesions were found in the hippocampus of adult male Wistar rats when they were treated with vitamin E. The drug vitamin E may have antioxidant and chemoprotective properties against methamphetamine-induced neurotoxicity.