Gamma radiation effects in the brain of rats: antioxidant and radioprotective properties of Vernonia amygdalina leaf extract

Abstract

Radiotherapy side effects have been attributed to free radical reactions. This study evaluated the antioxidant activity of the methanolic extract of V. amygdalina (MEVA) against gamma irradiation-induced oxidative stress in rats’ brain. Seventy male rats weighing 130-160 g were randomized into seven groups, with each group comprising ten rats namely: control, MEVA at 250, and 500 mg/kg/day, radiation only, radiation plus MEVA at 250, and 500 mg/kg/day, and alpha-tocopherol (TOCO). Rats were treated for 14 days, irradiated on the 15th day, and euthanized on the 16th day. Bioassays of malondialdehyde for lipid peroxidation (LPO), reduced glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD) were carried out using standard techniques. Some of the brains were processed for paraffin wax embedment and stained with haematoxylin and eosin. Data were analyzed using ANOVA. Radiation caused a significant (p<0.01) elevation in LPO by about 142%. Pretreatment with 250 mg MEVA, 500 mg MEVA and TOCO reduced LPO significantly (p<0.01) by 56%, 65%, and 80% respectively, when compared with rats that received gamma
radiation only. There was improvement in the histological alterations in the cerebellar layers and the Purkinje cell parameters of the pretreated groups when compared with the gamma-irradiated (R) group. MEVA
demonstrated antioxidant and radioprotective effects in rats’ brain.