Oxidative Stress and Neuronal Injury After Cannabis and Ketamine Administration

Abstract

Cannabis sativa and ketamine are common substances of abuse causing psychotic events and neurodegeneration. In this study, the effect of pretreatment with Cannabis sativa extract on oxidative stress, inflammatory mediators and brain damage induced by ketamine was investigated. Rats were treated with subcutaneous injections of cannabis extract (10, 20, 30 or 40 mg/kg; expressed as Δ9-THC content) daily for three weeks and then in combination with ketamine (15 mg/kg, intraperitoneally) for another 5 days. Rats were tested for biochemical markers of oxidative stress including malondialdehyde (MDA) reduced glutathione (GSH), and nitric oxide (NO) concentrations in brain. Paraoxonase-1 (PON-1) activity, and levels of the proinflammatory cytokines, interleukin-1β (IL-1β), and tumour necrosis factor-α (TNF-α) in brain were also determined at the end of treatment period. Results indicated that compared with the saline control group, ketamine induced significant elevation in brain MDA and NO, which was accompanied by depletion of GSH and inhibition of PON-1 activity. Ketamine also significantly increased brain IL-1β and TNF-α and induced neuronal necrosis, apoptosis and vacuolation. Cannabis sativa (20-40 mg/kg) pretreated rats showed lower levels of oxidative stress and inflammation and doses of 30 or 40 mg/kg slightly reduced neuronal apoptosis and necrosis. These findings suggest that cannabis constituents do not enhance the neurotoxic effects of ketamine and might partly counteract the effects of ketamine-induced NMDA antagonism by reducing the release of free radicals and inflammatory mediators in brain