Experimental Study on the Characteristics of Nerve Injury after Ischemia-Reperfusion and Their Recovery in Rats

ABSTRACT

OBJECTIVE: To analyze the degree of injury and patterns of recovery according to the severity and degree of ischemia-reperfusion. METHOD: Fifty-three rats were divided into 2 groups by degree of ischemia using ultrasonography. Each group was subdivided into 1 and 3-hours ischemia groups. Baseline recordings were performed, and ligation of the femoral vessels were done. Reperfusion process was done. Nerve conduction study (NCS), Sciatic Function Index (SFI) and histologic study were used. RESULTS: NCS parameters of the less than 3 hours incomplete insult group showed normal value. More than 1 hour of complete insult induced peripheral nerve injury. On first day and week, amplitude of NCS was small in 3-hour group. Muscle fiber diameter was less in 3-hour group. Although NCS parameters did not reach normal values on 4th week, 3-hour group showed smaller amplitudes. SFI returned to normal level at 4th week. Reperfusion injury was observed by electromyography. CONCLUSION: Less than 3 hours of partial ischemia/ reperfusion did not result in any form of injury whereas more than 1 hour of complete insult resulted in peripheral nerve injury with greater injury seen in 3 hour insult group. Neurological recovery was not achieved at 4 th week, and the more severe the ischemia, the poorer was the recovery.