An Experimental Study on Repeated Brief Ischemia in Promoting Sciatic Nerve Repair and Regeneration in Rats.

BACKGROUND

Research has shown that ischemic preconditioning reduced the severity of ischemia-reperfusion injury in brain in rats, we have a hypothesis that repeated brief ischemia has positive effects on peripheral nerve damage. This study was conducted to investigate the potential protective effects of repeated brief ischemia on peripheral nerve regeneration using a rat model of experimental sciatic nerve transection injury.

METHODS

Treatment groups (groups A-D) received repeated, brief ischemia every 1 day/2 days/3 days/7 days. After surgery for 4, 8, 12 weeks, we evaluated sciatic functional index test, gastrocnemius muscle wet mass, axon and nerve fiber diameter, density, G-ratio, immunohistochemistry of S-100, vascular endothelial growth factor (VEGF), and the ultrastructure of the nerves.

RESULTS

Sciatic functional index test and muscle wet mass were improved on the repeated brief ischemia groups. Ischemia treatment resulted in a significant increase in axon and nerve fiber density as well as S-100 and VEGF-positive cell, which indicated that repeated brief ischemia promotes Schwann cell proliferation and reconstruction.

CONCLUSIONS

This study exhibits the positive effects of repeated brief ischemia in sciatic nerve transection injury, possibly in part because it can improve VEGF and the physiologic state of Schwann cells in the ischemic environment and then accelerate the ability of neurite outgrow.