Objective To evaluate regenerative nerve and functional recovery of target muscle in rats with sciatic nerve defect bridged by acellular nerve allograft made through chemical extraction.Methods Sciatic nerve of SD rats was processed in a volume fraction of 3％ Triton X-lO0 solution and 40 g/L sodium deoxycholate solution.Morphology of myelin sheath,axons and basal lamina tubes of sciatic nerve segments was observed under the light microscopy before and after the chemical processing.Twenty-five Wistar rats were divided into acellular nerve allograft group (n =10),autograft group (n =10) and normal control group(n =5) according to the random number table.A 1 cm sciatic nerve defect was created in acellular nerve allograft group and autograft group,and was respectively bridged by acellular nerve allograft and autograft.Sciatic nerve function index (SFI) was measured every two weeks.Twelve weeks after surgery,nerve conduction velocity (NCV),recovery rate of compound muscle action potential (CMAP) and recovery rate of muscle force were measured in each group.Results Cellular components including myelin sheath and axons were removed thoroughly,but the basal lamina tubes were preserved completely.At postoperative 2,4,6,8,10 and 12 weeks,SFI in normal control group (-1.7±5.9,-0.3 ±2.5,0.8 ±4.1,-1.4±3.6,-2.5 ±5.7 and-2.1±3.2) was superior over autograft group (-94.3±3.7,-90.1±4.1,-63.7±7.8,-51.9±8.2,-48.8±8.6 and -44.3 ± 10.5) and acellular nerve allograft group (-97.1 ± 5.3,-91.2 ± 6.1,-70.6 ± 5.5,-60.4±6.2,-58.2 ±10.2 and-56.4 ±8.0) (P ＜0.01).At postoperative 6,8,10 and 12 weeks,SFI in autograft group were better than those in acellular nerve allograft group (P ＜0.05).NCV [(61.6 ± 8.1) m/s],recovery rate of CMAP[(98.7 ± 5.9) ％] and recovery rate of muscle force [(101.8 ± 6.6) ％] in normal control group were higher than those in acellular nerve allograft group [(22.3 ± 4.7) m/s,(40.3 ± 9.2) ％ and (43.8 ± 9.3) ％] and those in autograft group [(29.0 ±5.5) m/s,(52.5 ± 10.6) ％ and (54.3 ± 10.5) ％] (P ＜ 0.01).NCV,recovery rate of CMAP and recovery rate of muscle force in autograft group were better than those in acellular nerve allograft group (P ＜ 0.05).Conclusions Acellular nerve segments are harvested satisfactorily by chemical extraction.Sciatic nerve defect in rats can be cured with the acellular nerve allograft,but the repair effect of autograft is relatively better.