Changes of regenerative capacity in proximal sites following peripheral nerve section in rabbit

Abstract

To assess changes of regenerative capacity in proximal sites of sectioned peripheral nerve, we established an experimental model of nerve cross-anastomosis in rabbit. On the right hind limb, the proximal stump of peroneal nerve, which was left for various periods (8, 16, or 24 weeks) after nerve section, was sutured to the distal stump of tibial nerve immediately after tibial nerve section with epineural suture. On the left hind limb, cross-anastomosis was performed immediately after peroneal nerve section as a control. The sciatic nerve was subsequently stimulated on the sciatic notch, and compound muscle action potential was recorded from the gastrocnemius muscle every day after nerve suture. Regenerative capacity was then evaluated in terms of duration between the time the M response first became detectable and the time of nerve suture in each group. The duration differed significantly between the control group and each subgroup in the delayed suture group (P < 0.05). The duration correlated significantly with the interval between nerve section and suture (r = 0.746; P < 0.0001). In contrast to results hitherto regarded as valid, we concluded that the regenerative capacity of the proximal stump following peripheral nerve section decreased with time from 8 weeks after nerve section. Clinically, when we encounter a patient with suspected peripheral nerve section, it seems necessary to explore the injured nerve and suture the injured area without delay.