Effect Of Electroacupuncture On The Expression Of Glycyl-tRNA Synthetase And Ultrastructure Changes In Atrophied Rat Peroneus Longus Muscle Induced By Sciatic Nerve Injection Injury

Objective: The purpose of this study was to demonstrate the effect of electroacupuncture(EA) on the expression of glycyl-t RNA synthetase(Gly RS) and on the ultrastructure changes of the peroneus longus muscle after injection-induced sciatic nerve injury(SNI) in rats and to explore the preliminary mechanism underlying EA treatment on improving muscular atrophy from the perspective of protein synthesis.Methods: 1. Experimental animals grouping: One hundred and eight adult Sprague-Dawley(SD) rats(mean weight, 200 ± 50 g, 7 ~ 9 weeks old), either female or male were randomly selected. These animals were randomly divided into 4 groups, namely, control(CON), sciatic nerve injury(SNI), CON+EA, and SNI+EA. Of these, groups SNI, CON+EA, and SNI+EA were further divided into subgroups, i.e., the SNI group was administrated at 1 week, 2 weeks, 4 weeks, and 6 weeks after penicillin injection-induced sciatic nerve injury, respectively; the CON+EA group was administrated at 2 weeks and 4 weeks after EA stimulation of Huantiao(GB30) and Housanli(ST36) points of control SD rats, respectively; and the SNI+EA group was administrated at 2 weeks and 4 weeks after EA stimulation of GB30 and ST36 points respectively, 2 weeks after penicillin injection of sciatic nerve injury. Totally, there were 9 animal groups, and each group had 12 rats. 2. General observations. 3. Sciatic functional index(SFI) testing. 4. Peroneus longus muscle wet weight measurement. 5. Muscle fiber cross-section area measurement using image analysis software. 6. Ultrastructure changes observation under transmission electron microscope. 7. The changes of expression levels of Gly RS and myosin heavy chain ?b(MHC-?b) detection by RT-PCR and western blot technology. 8. The statistical data analysis by one-way ANOVA.Results: Compared with group CON, group SNI rats became limp and had to drag the injured leg at 1 week and 2 weeks. They also showed decreased SFI, peroneus longus muscle weight, muscle fiber cross-sectional area, and down-regulated m RNA and protein expression levels of Gly RS and MHC-?b, P<0.05, the differences were statistically significant; aggregated and vacuolated mitochondria, and swollen sarcoplasmic reticulum.The group SNI at 4 weeks showed decreased muscle weight and muscle fiber cross-section area sequentially, while there was a slight recovery about the other indicators. All the indicators had a slight recovery in varying degrees in group SNI at 6 weeks. The group CON+EA showed no significant changes, and there was no significant difference between group CON+EA and group CON, P>0.05. Compared with group SNI at 2 weeks, the group SNI+EA at 2 weeks and 4 weeks showed significant recovery, the degree of recovery was significantly greater than that of the group SNI at 4 weeks and 6 weeks, P<0.05, the differences were statistically significant.Conclusion: These results suggest that the peroneus longus muscle atrophy induced by penicillin injection sciatic nerve injury is associated with the down-regulated expression of Gly RS and the abnormal changes of ultrastructure in SD rats. EA stimulation of GB30 and ST36 points could alleviate peroneus longus muscular atrophy induced by iatrogenic sciatic nerve injury through promoting the expression of Gly RS, increasing muscle protein synthesis, and the recovery of muscle cell ultrastructure.