Fig. 4: Impaired muscle regeneration in GPNMB-KO mice after CTX injury.

a Western blot analysis confirmed the absence of GPNMB expression in GPNMB-KO mice compared with WT mice. b A schematic of the experimental design for assessing muscle regeneration in GPNMB-KO and C57BL/6 control mice after CTX injection. Mice were injected with CTX on day 0, and the TA muscles were collected for histopathological analysis on days 4 and 7 after injury. c Representative images of TA muscles from GPNMB-KO and WT mice that are uninjured and at days 4 and 7 after injury, demonstrating differences in muscle morphology. The GPNMB-KO mice exhibited impaired muscle regeneration with less striated muscle fibers than WT mice. d H&E staining of TA muscle sections revealed histological changes during regeneration, with GPNMB-KO mice showing reduced tissue repair compared with controls. e Quantitative analysis of CSA of muscle fibers in uninjured, day 4 post-injury and day 7 post-injury muscle sections confirmed statistically significant impairment of regeneration in GPNMB-KO mice.