RESUMO
OBJECTIVE: To observe the effect of oblique needling at Ashi-point on behavior, and cell morphology, myogenic differentiation antigen (MyoD1) and paired box transcription factor Pax7 (Pax7) of quadriceps femoris tissue in quadriceps femoris injured mice. METHODS: A total of 24 C57BL/6 male mice were randomly divided into control, model, shallow insertion and deep insertion groups, with 6 mice in each group. The quadriceps femoris injury model was established by single intramuscular injection of 0.5% bupivacaine (BPVC). Twenty-four hours after modeling, mice of the two acupuncture groups were received oblique needling on the surface or through the muscle belly of quadriceps femoris for once, the oblique needling was lifted and inserted 3 times. The climbing pole test was conducted 24 h after modeling and 24 h after EA. Histopathological changes of quadriceps femoris was observed by H.E. staining. The expressions of MyoD1 and Pax7 were detected by immunohistochemistry. RESULTS: Compared with the control group, the score of climbing pole test was lower (P<0.01), and the expressions of MyoD1 and Pax7 significantly increased (P<0.01) in the model group. After the intervention and compared with the model group, the score of climbing pole test was higher (P<0.01), and the expressions of MyoD1 and Pax7 obviously increased (P<0.01) in the two acupuncture groups. The therapeutic effect of deep insertion group was apparently superior to that of shallow insertion group in up-regulating the climbing pole test score and expressions of MyoD1 and Pax7 (P<0.05, P<0.01). H.E. stain showed large areas of inflammatory infiltration, muscle cells swelling, atrophy, rupture, degeneration and necrosis, different cell sizes and morphologies, enlarged intervals, nuclear aggregation, deep nuclear staining, nuclear pyknosis, and hemorrhage in the model group, which was relatively milder in both needling groups. CONCLUSION: Oblique needling at Ashi-point can effectively promote the benign repair of injured quadriceps muscle and promote the recovery of exercise ability in mice, which may be associated with its effect in up-regulating the expression of MyoD1 and Pax7 protein. The role of deep insertion is superior to that of shallow insertion.