Sciatic denervation differentially remodels skeletal muscle and deep fascia in the lower limb of male mice.

The deep fascia surrounds skeletal muscles and contributes to force transmission and mechanical coordination, but its response to denervation remains unclear. This study investigated morphological and transcriptional adaptations of the deep fascia following sciatic nerve denervation in mice. Male C57BL/6J mice (n = 5-6/group) underwent unilateral sciatic nerve denervation or sham surgery. Fourteen days later, tibialis anterior (TA) muscle and overlying deep fascia (anterior crural fascia) were analyzed by histology and quantitative PCR. Denervation induced significant TA muscle atrophy with upregulation of inflammatory (Il6, p = 0.001), profibrotic (Tgfb, p < 0.001), and extracellular matrix (ECM)-related genes (Mmp2, p = 0.006; Col3a1, p = 0.005), and downregulation of regenerative factors (Fgf2, p < 0.001). Deep fascia thickness increased approximately 1.5-fold (p = 0.012) and was accompanied by elevated Il6 (p < 0.001), Tgfb (p = 0.035), Col1a1 (p = 0.006), and Col3a1 (p = 0.003) expression and a higher proportion of collagen type III (p = 0.015). In conclusion, sciatic nerve denervation induces muscle atrophy and deep fascia thickening accompanied by extracellular matrix remodeling. These findings demonstrate coordinated yet tissue-specific remodeling of skeletal muscle and deep fascia following sciatic nerve denervation.