Nigella sativa conserved hippocampal oxidative and neurogenic activities to salvage neuro-cognitive integrities in chlorpyrifos insult

Abstract

Chlopyrifos (CPF) is an organophosphate, implicated in brain damage and cognitive deficits, whose consistence deposit in the environment has contributed to the toxicity burdens of xenobiotics. This study investigated the efficacy of Nigella sativa oil (NSO) against CPF insults on the hippocampus. Thirty-two rats were randomly divided into four groups of eight rats each, exposed to 1 ml/kg of Normal saline, 14.9 mg/kg of CPF, 14.9 mg/kg of CPF plus 1 ml/kg of NSO and 1 ml/kg of NSO respectively for 14 consecutive days. The rats were exposed to 3 trials each on the 11–13 days in the Morris water maze, and subsequently latency to hidden platform and time in the platform quadrant were recorded as measures of long term memory (LTM), short term memory (STM) and reference memory (RM) on the 14th day. The rats were euthanized on day 15, the brains excised, and the hippocampus of five brains removed, homogenized to analyze for total reactive oxygen species (ROS), nitric oxide (NO) levels and acetylcholinesterase (AChE) activities, while the other three were processed for histology and Ki67 immunohistochemistry. CPF caused a marked increase in hippocampal NO and ROS activities, depleted AChE activities and Ki67 expressions, delayed escape latency and reduced visit to the platform quadrant. Intervention with NSO depleted ROS/NO levels, improved neurogenic proteins, AChE activities and neuro-cognitive markers depletions in CPF exposure. Altogether, our findings showed that NSO is a potential therapeutic drug for the treatment of CPF-induced cognitive deficit through its antioxidant property and adult neurogenesis in rats. Keywords: Nigella sativa oil, Organophosphates, Oxidative damage, Acetylcholinesterase, Cognition