Effect and Mechanism of Massage Manipulation on Rats with Skeletal Muscle Overuse Injury Based on Wnt/β-catenin Signaling Pathway

<bold>Objective</bold> To observe the effect and its mechanism of massage manipulation on the repair and regeneration of skeletal muscle overuse injury in rats based on Wnt/β-catenin signaling pathway. <bold>Methods</bold> A total of 42 SD rats were randomly divided into blank group, model group and intervention group, with 14 cases in each group. Armstong centrifugal exercise program was used to establish the rat skeletal muscle overuse injury model in the model group and the intervention group, except for the blank group. Medical vaseline was smeared on the right hindlimb gastrocnemius muscle and adjacent muscles in the blank group and the model group, but no massage manipulation was given. Massage manipulation was given at the right hind gastrocnemius muscle in the intervention group, with the pressure of about 2 N, the frequency of 80 beats per minute, three minutes a time, once in the morning and once in the afternoon, lasting for three days. At 24 h after modeling and 24 h after intervention, the balance beam test was used to assess the motor function of rats with skeletal muscle injury; hematoxylin-eosin (HE) staining method was used to observe the pathological changes of the gastrocnemius muscle; an EM-1400 transmission electron microscope was used to observe the ultrastructure of the skeletal muscle fibers; fluorescence PCR was used to detect the myogenic regulatory factors including myogenic differentiation antigen (MyoD), myogenin (MyoG) and paired box gene 7 (Pax7) mRNA transcript levels; Western blot was used to detect MyoD, MyoG, Pax7, Wnt3a, Axin2 and β-catenin protein expression levels. <bold>Results</bold> (1) Motor function: compared with the blank group, the time to pass the balance beam and the number of paw slips in the model group and the intervention group increased significantly, and the differences were statistically significant (<italic>P</italic>&lt;0.05). Compared with the model group, the time to pass the balance beam and the number of paw slips in the intervention group decreased significantly after intervention, and the differences were statistically significant (<italic>P</italic>&lt;0.05). (2) Histopathological changes in gastrocnemius muscle tissue: the model group showed a large number of cracks within the muscle cells and broken myofibrils in the gastrocnemius muscle; compared with the model group, the intervention group had a reduced degree of muscle tissue damage, and the muscle fibers were in regular morphology and arranged in order. (3) Ultrastructural changes in gastrocnemius muscle tissue: the local myofibril bundles in the model group were broken and dissolved, and a small amount of Z-line structure was dissolved and blurred. Compared with the model group, the gastrocnemius muscle cells in the intervention group were slightly edematous; the myofibril bundles showed clear structure; some myofibril bundles were broken, and the Z-line structure was clear and arranged neatly. (4) Transcriptional levels of MyoD, MyoG and Pax7 in gastrocnemius muscle tissue: compared with the blank group, the transcriptional levels of MyoD, MyoG and Pax7 in the model group and the intervention group were significantly higher (<italic>P</italic>&lt;0.05); compared with the model group, the transcriptional levels of MyoD, MyoG and Pax7 in the intervention group were significantly higher (<italic>P</italic>&lt;0.05). (5) Protein expression levels of MyoD, MyoG and Pax7 in gastrocnemius muscle tissue: compared with the blank group, protein expression levels of MyoD, MyoG and Pax7 in the model group and the intervention group were significantly higher (<italic>P</italic>&lt;0.05); compared with the model group, protein expression levels of MyoD, MyoG and Pax7 in the intervention group were significantly higher (<italic>P</italic>&lt;0.05). (6) Protein expression levels of Wnt3a, Axin2 and β-catenin in gastrocnemius muscle tissues: compared with the blank group, protein expression levels of Wnt3a, Axin2 and β-catenin in the model group and the intervention group were significantly higher (<italic>P</italic>&lt;0.05); compared with the model group, protein expression levels of Wnt3a, Axin2 and β-catenin in the intervention group were significantly higher (<italic>P</italic>&lt;0.05). <bold>Conclusion</bold> Massage manipulation can improve the gastrocnemius muscle injury and motor function in rats with skeletal muscle overuse injury, and its mechanism may be related to the activation of Wnt/β-catenin signaling pathway.