Nauclea latifolia stem-bark extract protects the prefrontal cortex from valproic acid - induced oxidative stress in rats: Effect on B-cell lymphoma and neuron specific enolase protein expression

Nauclea latifolia stem-bark (NLS) is widely utilized for broad spectrum pathologies. The study evaluated the protective effects of NLS extract supplemented along with valproic acid on oxidative stress markers, and neuron specific enolase (NSE) and B cell lymphoma 2 (bcl-2) protein expressions in prefrontal cortex of rats. The NLS extract was administered in three doses (50, 100, 200mg/kg) after pre-treatment of the experimental animals with high dose valproic acid (VPA) (500 mg/kg) orally daily by subacute exposure for 28 days. The rats were sacrificed and the prefrontal cortex (PFC) of the brain abstracted and homogenized in ice for biochemical assays to estimate the levels oxidative stress markers; histopathological examination to reveal the histomorphorgical changes and immunohistochemistry to examine effect on NSE andbcl-2protein expressions. The findings revealed significant (P < 0.05 – 0.001) elevation of oxidative stress induced by VPA. The NLS extract supplementation mediate significant elevation of the levels of reduced glutathione (P< 0.05 – 0.01), antioxidant enzymes [glutathione peroxidase (P< 0.001), superoxide dismutase (P < 0.001), catalase (P< 0.05 – 0.01) and glutathione-s-transferase (P < 0.05 – 0.01)] and significant decline of lipid peroxidation marker, malondialdehyde, (NLS group vs diseases control group (P < 0.001). The NLS extract studied down-regulated NSE at the prefrontal cortex preventing neuronal damage but no effect on bcl-2 protein expression. We conclude that NLS extract has potential to mitigate VPA induced neurotoxicity by obliterating oxidative stress and down regulating NSE expression, effects demonstrating probable therapeutic role in neurodegenerative diseases.