OBJECTIVETo observe effects of electroacupuncture (EA) at "Weizhong" (BL 40) on morphology and expression of creatine kinase (CK) and interleukin-17 (IL-17) in rats with bupivacaine-induced multifidus muscle injury.

METHODSA total of 32 male SD rats were randomly divided into a control group, a model group, a Weizhong group and a Shenshu group, 8 rats in each one. The rats in the model group, Weizhong group and Shenshu group were treated with intramuscular injection of 0.5% bupivacaine to establish the model of multifidus muscle injury; the rats in the control group were injected with 0.9% sodium chloride solution. The rats in the Weizhong group and Shenshu group were treated with EA (2 Hz/10 Hz in frequency, 1~2 mA in intensity) at "Weizhong" (BL 40) and "Shenshu" (BL 23), 20 min per treatment. No treatment was given in the control group and model group. After 14-day treatment of EA, the inflammatory cell count, scar tissues area and muscle fiber cross sectional area of multifidus muscle were observed with HE and Masson staining method. The activity of CK and serum content of IL-17 were test with enzyme-linked immunosorbent assay (ELISA) method; the expression of IL-17 in multifidus muscle was measured with immunohistochcmical method.

RESULTSAfter intervention, the inflammatory cell count and scar tissues area in the model group, Weizhong group and Shenshu group were higher than those in the control group (all<0.01), but the muscle fiber cross sectional area was significantly reduced (all<0.01); the inflammatory cell count and scar tissues area in the Weizhong group and Shenshu group were lower than those in the model group (all<0.01), and the muscle fiber cross sectional area was significantly increased (<0.01,<0.05). After intervention, the expression of IL-17 in multifidus muscle, serum content of IL-7 and activity of CK in the model group, Weizhong group and Shenshu group were higher than those in the control group (all<0.01); the expression of IL-17 in multifidus muscle, serum content of IL-7 and activity of CK in the Weizhong group and Shenshu group were lower than those in the model group (<0.01,<0.05); compared with the Shenshu group, the down-regulation of IL-17 was more obvisous in the Weizhong group (<0.01).

CONCLUSIONEA at "Weizhong" (BL 40) can down-regulate the overexpression of serum CK and IL-17, alleviate inflammation reaction and improve the repair of multifidus muscle.