Protective Efficacy of Coenzyme Q10 Against DDVP-Induced Cognitive Impairments and Neurodegeneration in Rats

The present study was carried out to elucidate the effects of coenzyme Q10 (CoQ10) against cognitive impairments induced by dichlorvos (DDVP). We have previously shown organophosphate, DDVP-induced impairments in neurobehavioral indices viz. rota rod, passive avoidance, and water maze tests. In addition to this, we have also reported that chronic DDVP exposure leads to decreased mitochondrial electron transfer activities of cytochrome oxidase along with altered mitochondrial complexes I–III activity. Administration of CoQ10 (4.5 mg/kg, i.p. for 12 weeks prior to DDVP administration daily) to DDVP-treated rats improved cognitive performance in passive avoidance task and Morris water maze test. Furthermore, CoQ10 treatment also reduced oxidative stress (as evident by reduced malondialdehyde, decreased ROS and increased Mn-SOD activity) in DDVP-treated rats’ hippocampus region, along with enhanced activity of complexes I–III and complex IV. Electron microscope studies of rat hippocampus mitochondria revealed that CoQ10 administration leads to near normal physiology of mitochondria with well-defined cristae compared with DDVP-treated animals where enlarged mitochondria with distorted cristae are observed. CoQ10 administration also attenuated neuronal damage in hippocampus as evident from histopathological studies. These results demonstrate the beneficial effects of CoQ10 against organophosphate-induced cognitive impairments and hippocampal neuronal degeneration.