To investigate whether aspirin promotes the repair of peripheral nerve injury.

Thirty SD rats were randomly divided into two groups: an experimental group (A) and a control group (S). The left sciatic nerve of all rats was severed and anastomosed under a microscope. The rats in group A were treated with aspirin, and those in group S were given the same amount of saline. The sensory nerve regeneration distance was measured at the second, fourth, and sixth weeks after operation. The bilateral gastrocnemius muscle was weighed and the recovery rate of wet weight was calculated at the second, fourth, sixth, and eighth weeks after operation. The sciatic nerve conduction velocity was measured, and the number of Schwann cells in each field of view was calculated using Olympus software. The number of Schwann cells in each visual field was also calculated by immunohistochemical S-100 staining at the fourth and eighth weeks after operation. The proliferation of Schwann cells and the changes of myelin sheath were observed by electron microscopy at the eighth week after operation. Comparison between groups was performed using the t test, and P<0.05 was considered to have statistical difference.

The regeneration distance of sensory nerve was significantly longer in group A than in group S at the second [(16.54±1.43)mm vs (9.73±1.21)mm, t=-8.131 3, P<0.001], fourth [(18.04±1.08)mm vs (13.20±1.1)mm, t=-13.104, P<0.001], and sixth weeks [(22.67±1.27)mm vs (15.19±0.57)mm, t=-5.746, P<0.001] after operation. There was no significant difference in muscle wet weight ratio between groups A and S at the second week postoperatively (0.955±0.011 vs 0.944±0.013, t=-1.695, P=0.132), but a significant difference was observed at the fourth (0.872±0.005 vs 0.828±0.057, t=-13.104, P<0.001), sixth (0.798±0.007 vs 0.764±0.0128, t=-5.746, P<0.001), and eighth weeks (0.783±0.011 vs 0.741±0.008, t=-6.123, P<0.001) after operation. Electrophysiology of group A was significantly superior to that of group S [(31.99±1.22)ms vs (21.06±0.78)ms, t=16.776, P<0.001]. The latency of group A was significantly lower than that of group S [(18.71±1.49)ms vs (30.84±1.36)ms, t=-13.695, P<0.001]. The amplitude of group A was significantly higher than that of group S [(5.58±0.55)mV vs (4.42±0.58)mV, t=3.224, P=0.012]. The recovery rate of conduction velocity in group A was significantly better than that of group S [(76.5±20.8)% vs (63.9±26.1)%, t=8.370, P<0.001]. The number of Schwann cells expressing S-100 protein was significantly higher in group A than in group S at the fourth [(442.00±35.36)cells vs (242.80±24.33)cells, t=-10.378, P<0.001] and eighth weeks [(928.00±43.25)cells vs (552.80±65.23)cells, t=-10.719, P<0.001] after operation. Electron microscopy showed that the distribution of myelin sheath was better in the aspirin group than in the control group at each time point, and the thickness was more uniform and neat.

Aspirin can promote the repair of peripheral nerve injury.