Neuroprotective effect of diclofenac on chlorpromazine induced catalepsy in rats

Neuroinflammation plays a key role in progressive degeneration of dopaminergic cells. Upregulation of prostaglandins and free radicals formation are involved in the mechanisms of cell death in Parkinson's disease (PD). The present study aimed to investigate the neuroprotective effect of diclofenac against chlorpromazine (CPZ) induced catalepsy and motor impairment in mice. Adult Wistar rats treated with CPZ (3 mg/kg/day, IP) were orally dosed with diclofenac and L-dopa/carbidopa for 21 days. Catalepsy was measured after 21 days of dosing by using standard bar test at 30, 60, 90, 120 and 180 min then motor performances were assessed via open field test and wire hanging test. Histopathological investigation and determination of dopamine (DA) and 3,4-Dihydroxyphenylacetic acid (DOPAC) levels of rat's brain was also carried out. We found that CPZ treated group exhibited reduced motor impairment after 21 days of treatment in open field and wire hanging test (P < 0.01) as compared to control group. The cataleptic scores of CPZ treated rats were also significantly increased (P < 0.01) after 21 days of chronic dosing, however diclofenac treated groups showed significant reduction in cataleptic scores with improved motor performances. Histopathology of CPZ treated rats showed marked degeneration with architecture distortion in the mid brain region. Dopaminergic degeneration is confirmed by neurochemical results that showed reduced amount of dopamine and DOPAC levels in mid brain. Moreover, histopathological slides of diclofenac treated rats showed improved architecture with reduced gliosis of mid brain region as well as improved dopamine and DOPAC levels were achieved after 21 days dosing of diclofenac. Taken together, the present work provide an evidence that diclofenac ameliorated behavioral performances by mediating neuroprotection against CPZ induced PD via preventing dopaminergic neuronal cell death.