Effectiveness of gua sha with Masanggoubang oil in rats with chronic soft tissue injury

Chronic soft tissue injury is characterized by sterile inflammation and pain. Gua sha with Masanggoubang oil (GSMO) treatment has been found to possess anti-inflammatory and analgesic effects. To explore the mechanism of GSMO in chronic soft tissue injuries. Fifty male rats were randomly divided into 5 groups (n = 10): 1) control group; 2) chronic soft tissue injury model group; 3) GSMO group; 4) inunction with Masanggoubang oil (IMO) group; and 5) ua sha with tea oil (GSTO) group. The control group and model group received no treatment, while the GSTO group and GSMO group received gua sha therapy with tea oil or Masanggoubang oil on the injured sites. The rats in the IMO group were treated with Masanggoubang oil inunction on the injured sites once every other day, 4 times in total. All animals were sacrificed 48 h after the last treatment. Muscle tissue sections from the injured sites of the rats were stained with hematoxylin & eosin (H&E) staining to observe pathological changes. The protein levels of tumor necrosis factor alpha (TNF-α), interleukin 1β (IL-1β), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and β-endorphin (β-EP) in the rats' skin, serum, and muscle were determined using enzyme-linked immunosorbent assay (ELISA). Gua sha with Masanggoubang oil treatment alleviated necrosis and the denaturation of muscle fibers at the injured sites, reduced connective tissue proliferation and scar tissue generation, downregulated the levels of TNF-α, IL-6 and iNOS in the skin and TNF-α, IL-1β, IL-6, and iNOS in the muscle and serum, and upregulated β-EP levels in the muscle. Gua sha with Masanggoubang oil treatment significantly improved the inflammatory response in rats with chronic soft tissue injury, which may be associated with a reduction of M1 macrophage polarization in the peripheral blood and local tissues. Additionally, the combination of gua sha therapy and Masanggoubang oil may have a synergistic effect in treating chronic soft tissue injuries.