Effect of electroacupuncture on the expression of agrin and acetylcholine receptor subtypes in rats with tibialis anterior muscular atrophy induced by sciatic nerve injection injury

OBJECTIVE: To investigate the effects of electroacupuncture (EA) on mRNA and protein expression of agrin, acetylcholine receptor (AChR)-ε and AChR-γ in a rat model of tibialis anterior muscle atrophy induced by sciatic nerve injection injury, and to examine the underlying mechanism of action. METHODS: Fifty-four adult Sprague-Dawley rats were divided into four groups: healthy control group (CON, n=6); sciatic nerve injury group (SNI, n=24), comprising rats euthanased at 1, 2, 4 and 6 weeks, respectively, after penicillin injection-induced SNI (n=6 each); CON+EA group (n=12), comprising healthy rats euthanased at 4 and 6 weeks (after 2 and 4 weeks, respectively, of EA at GB30 and ST36); and SNI+EA group, comprising rats euthanased at 4 and 6 weeks (after 2 and 4 weeks, respectively, of EA). The sciatic nerve functional index (SFI), tibialis anterior muscle weight, muscle fibre cross-sectional area (CSA), and changes in agrin, AChR-ε, and AChR-γ expression levels were analysed. RESULTS: Compared with the control group (CON), SNI rats showed decreased SFI. The weight of the tibialis anterior muscle and muscle fibre CSA decreased initially and recovered slightly over time. mRNA/protein expression of agrin and AChR-ε were downregulated and AChR-γ expression was detectable (vs zero expression in the CON/CON+EA groups). There were no significant differences in CON+EA versus CON groups. However, the SNI+EA group exhibited significant improvements compared with the untreated SNI group (p<0.05). CONCLUSIONS: EA may alleviate tibialis anterior muscle atrophy induced by sciatic nerve injection injury by upregulating agrin and AChR-ε and downregulating AChR-γ.