Anti-oxidant activity mediated neuroprotective potential of trimetazidine on focal cerebral ischaemia-reperfusion injury in rats

1. The present study was designed to investigate the neuroprotective effect of trimetazidine (TMZ) following focal cerebral ischaemia-reperfusion (I/R) injury in rat forebrain. 2. Cerebral I/R injury was induced in rats by middle cerebral artery occlusion (MCAO) for 2 h, followed by reperfusion for 22 h. Trimetazidine (5 and 25 mg/kg, i.p.) was administered 1 h after induction of MCAO. The effects of TMZ were investigated by measuring neurological deficit, volume of infarct and brain swelling after 22 h reperfusion. Oxidative stress and inflammatory reactivity were assessed by estimating anti-oxidant markers and myeloperoxidase (MPO) activity in brain homogenates. Rectal temperature was measured during the study. The effects of TMZ on blood-brain barrier (BBB) permeability and apoptosis were also investigated in rat brain. Apoptosis was observed by DNA fragmentation studies using agarose gel electrophoresis. 3. Treatment with TMZ significantly (P < 0.01) reduced infarct volume and brain swelling. Superoxide dismutase (SOD) activity was reduced in ipsilateral hemispheres of vehicle (saline)-treated reperfused (RI) animals. Treatment with TMZ significantly restored SOD activity (P < 0.01) and glutathione levels (P < 0.05) after reperfusion compared with RI animals. Lipid peroxidation, MPO activity, BBB permeability and rectal temperature were all significantly (P < 0.01, P < 0.05 and P < 0.001, respectively) reduced in TMZ-treated animals compared with RI animals. 4. These results suggest that TMZ protects the brain against cerebral I/R injury and that this neuroprotective activity could be mediated by its anti-oxidant properties. The reduction in rectal temperature by TMZ treatment may be responsible for maintaining the delicate energy balance during I/R injury in rat brain and could have contributed to the neuroprotective activity of TMZ.