Effect of epineural or intraneural injection of ropivacaine on acutely injured sciatic nerve in rats / 中华麻醉学杂志

ABSTRACT

Objective To investigate the effects of 1% ropivacaine injected epineurally or intraneurally on the recovery of sciatic nerve from acute injury in rats. Methods Seventy-two healthy male Wistar rats weighing 220-250 g were xandomly assigned into 4 groups ( n = 18 each): group Ⅰ epineural injection of normal saline(NS)(group C1); group Ⅱ intraneural injection of NS (group C2); group Ⅲ epineural injection of 1% ropivacaine (group Epi-R) and group Ⅳ intraneural injection of 1% ropivacaine (group Intra-R). The animals were anesthetized with intraperitoneal 3% pentobarbital 60 mg/kg. The sciatic nerve was exposed and crushed with blood vessel clamp for 2 min. NS or 1% ropivacaine 0.2 ml was injected epineurally or intraneurally after release of the clamp.Sciatic nerve function was measured and sciatic nerve function index (SFI) was calculated at day 1, 3, 7, 14, 21and 28 after operation. Six animals in each group were anesthetized on the 14th and 28th day after operation and the nerve conduction velocity (NCV) of the sciatic nerve was measured. The sciatic nerve was then removed for histologic examination. Results There was no significant difference in SFI and NCV at all time points among group C1 , C2 and Epi-R. SFI was almost normal on the 28th day after operation in the 3 groups. The NCV was significantly slower at day 14 and 28 after operation in intra-R group than in the other 3 groups. Conclusion Intra-neural injection of ropivacaine can significantly delay the recovery of sciatic nerve from acute injury.