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

Abstract

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.