The effects of simvastatin on ischemia-reperfusion injury of sciatic nerve in adult rats.

Severe ischemia to nerve results in fiber degeneration and reperfusion results in oxidative injury to endothelial cells and augments fiber degeneration. Statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, the most widely used lipid-lowering drugs, have been demonstrated to play a neuroprotective role. So we evaluated the effectiveness of simvastatin in protecting sciatic nerve from ischemia-reperfusion injury using the model of experimental nerve ischemia. Sixty adult male Sprague-Dawley rats weighing 250-300 g were used. They were divided into ten groups (N=6 per group). We used ischemia model in these groups by occluding the femoral artery and vein with a silk suture 6-0 using slipknot technique. All ischemia groups were rendered in ischemic for 3 h reperfused for various times of zero (0 h), 3 h (3 hour reperfusion), 7 days (7 day reperfusion), 14 days (14 day reperfusion). Half of the groups had experimental simvastatin (1 mg/kg) i.v. injection treatment via tail vein 1 h before ischemia. The other half experienced only ischemia-reperfusion as control groups. After euthanasia, histological samples were taken from distal part of the sciatic nerve. Sections were cut at 5 microm and then were stained with H and E and modified trichrome. We used H and E stain for edema and trichrome gomori for ischemic fiber degeneration. Samples were observed to assess their fiber degeneration and edema changes. By observation the level of fiber degeneration and endoneurial edema were also decreased in these recent groups (in both ischemia and reperfusion duration). In conclusion, pre-ischemic administration of simvastatin exhibits neuroprotective properties in ischemia-reperfusion nerve injury.