Mechanistic effects of percutaneous needle fasciotomy combined with stretching on early-stage skeletal muscle fibrosis in rats: focus on the TGF-β1/Smad signaling pathway.

BACKGROUND: To investigate the effects of combination combining Percutaneous Needle Fasciotomy (PNF) with stretching(Str) on early-stage skeletal muscle fibrosis in rats, focusing on the transforming growth factor beta-1 (TGF-β1)/Smad signaling pathway. METHODS: Twenty-four male Wistar rats were randomly divided into Control, immobilization(imm), Acupuncture(Apu) + Str, and PNF + Str groups (n = 6 each). After establishing a gastrocnemius fibrosis model by 4-week ankle imm in the right hindlimb ankle, intervention groups received either PNF (0.35 × 25 mm needle insertion with fascial release) or Apu (following an identical protocol), both combined with daily passive Str (3-N dorsiflexion for 7 days). Post-intervention assessments included functional tests (ankle joint range of motion, hindlimb grip strength, andgastrocnemius twitch/tetanic contractile forces), histological evaluation (collagen content via Masson's trichrome staining and immunofluorescence), and molecular analysis of TGF-β1/Smad pathway components. RESULTS: Compared to the imm group, the PNF + Str group exhibited significantly better muscle performance, reduced histopathological damage, and favorable modulation of TGF-β1/Smad signaling markers. Importantly, these improvements were more pronounced than those in the Apu + Str group, wich demonstrates PNF's superior therapeutic effects in enhancing functional recovery, reducing fibrosis, and regulating the TGF-β1/Smad pathway. CONCLUSION: Our findings from this animal model demonstrate that PNF was superior to Apu in alleviating early-stage skeletal muscle fibrosis over the short term, potentially via modulation of the TGF-β1/Smad signaling pathway, though long-term effects warrant further investigation.