Neuroprotective Effects of Vitamin B Complex on the Hippocampus and Prefrontal Cortex of Methamphetamine - Induced Adult Male Wistar Rats

Abstract

Methamphetamine is a potent central nervous system stimulant that causes profound neurotoxic effects on the hippocampus and prefrontal cortex, regions critical for memory, cognition, and emotional regulation. This study investigated the protective role of vitamin B complex against methamphetamine-induced neurotoxicity in adult male Wistar rats. Twenty-eight rats were randomly assigned into seven groups (A–G, n = 4). Group A served as the control, Groups B and C received methamphetamine at 2 mg/kg and 10 mg/kg respectively, while Groups D and E were administered vitamin B complex at 50 mg/kg and 100 mg/kg respectively. Groups F and G received combined treatments, with Group F administered 2 mg/kg of methamphetamine (low dose) plus 50 mg/kg of vitamin B complex (low dose), and Group G receiving 10 mg/kg of methamphetamine (high dose) plus 100 mg/kg of vitamin B complex (high dose). Sub-chronic oral administration was carried out, and parameters assessed included body weight, relative organ weight, and histological architecture of the hippocampus and prefrontal cortex. Rats treated with methamphetamine alone (Groups B and C) exhibited significant weight loss (p < 0.01), increased relative organ weights, and marked histopathological alterations characterized by reduced normal pyramidal cell counts and increased inflammatory cell infiltration, indicating severe neuronal degeneration. Conversely, rats treated with vitamin B complex, either alone or in combination (Groups D–G), demonstrated significant weight gain, relative organ weights comparable to the control, and preservation of hippocampal and prefrontal cortex histoarchitecture. These groups showed increased numbers of normal pyramidal cells with reduced inflammatory changes compared to methamphetamine-only groups, suggesting enhanced neuroprotection. In conclusion, vitamin B complex mitigated methamphetamine-induced neuronal degeneration, improved body weight, and preserved cortical and hippocampal integrity. These findings highlight the potential therapeutic role of vitamin B complex in reducing stimulant-induced brain injury and support its possible application as a neuroprotective agent.