ABSTRACT
BACKGROUND: Local soft tissue lysis has been widely used in clinical rehabilitation treatment of chronic soft tissue injuries, and has achieved certain clinical outcomes. However, it is an invasive treatment, and there is little information about the pathological changes and prognosis of the local tissues post-treatment. OBJECTIVE: To observe the repair process and pathologic changes of the muscles after local soft tissue lysis with several needles. METHOD:Songjin-needle,Yinzhi-needle,Changyuan-needle,Xiaozhen-needle,Ren-needle and Pi-needle were inserted into the belly of rat gastrocnemius gastrocnemius with a depth of 0.5-1.0 cm, twice or thrice. Then the rats were killed at 3, 7, 14, 21 and 30 days after acupuncture. The corresponding parts of tissues were removed and fixed with paraformaldehyde, and stained with hematoxylin and eosin and immunohistochemistry to observe the histomorphological features and pathological changes under light microscope. The CellSens-Entry 1.15 software was used for image acquisition, and the number of fibroblast cells and microvessel density were calculated. The integral absorbance values of collagen type Ⅰ were calculated by Image Pro plus 6 software. RESULTS AND CONCLUSION: On day 3 after intervention, muscle fiber dissolution, necrosis and inflammatory cell infiltration were visible. On day 7, there was a reduction in inflammatory cells, fibroblast activation and proliferation, and granulation tissue hyperplasia. On day 14, there was local accumulation of collagen with substantial granulation tissues. On day 21, collagen fibers decreased and granulation tissues organized. On day 30, there was local scar formation. Immunohistochemical staining results showed that there was collagen type Ⅰ in the surgical area after intervention. The microvessel density, fibroblast count and integral absorbance value increased firstly and then decreased, which showed significant differences among groups (P < 0.01). These findings imply that the new types of needles for local soft tissue lysis do certain damage to the gastrocnemius muscle, and the inflammatory changes of the local tissue and granulation tissue organized will result in local scar formation after loosening therapies.