Nerve Blood Flow during Hindlimb Ischemia and Reperfusion in Rats

Animal models of peripheral nerve ischemia have yielded variable results.

The question of whether postischemia re-estableshment of blood flow to the nerves auguments injury has not been examined.

To study this question, the ipsilateral common iliac and femoral arteries were occluded with arterial snares for 3 hours in rats. C14-butanol tissue distribution was then used to measure blood flow in both sciatic and posterior tivial nerve trunks during occlusion and reperfusion.

Clinical limb function was graded serially, with the undisturbed contralateral limb serving as the study control. Nerve blood flow was reduced throughout the ischemic period and was only 20% of the control value in the posterior tibial nerve. All rats had functional impairment with an average limb function score of 7.5(normal score<2). During reperfusion period, blood flow in the distal sciatic and posterior tibial nerves was approximately double that of control nerbes at 2 hours.

At 21 hours, tibial nerve blood flow was still twice that of the control nerve, but flows in the distal sciatic nerve were unchanged from control levels. Clinically, limb function improved progressively after reperfusion.

It was concluded that nerve ischemia is attended by a relatively prolonged hyperemic flow response during reperfusion.