[Huangqi Guizhi Wuwu Detection regulates mitochondrial quality control and autophagy-lysosome flux to ameliorate skeletal muscle pathology in rheumatoid arthritis-associated sarcopenia].

This study investigated the mechanisms by which Huangqi Guizhi Wuwu Detection(HQGZWWT) ameliorates skeletal muscle injury, mitochondrial dysfunction, inflammatory responses, and autophagic flux in rheumatoid arthritis(RA)-associated sarcopenia from the perspective of the "mitochondrial quality control and autophagy-lysosome flux". The collagen-induced arthritis(CIA) rat model was adopted. Rats were divided into a blank group, a model group, and HQGZWWT treatment groups with different doses: low(1.22 g·kg~(-1)), medium(2.44 g·kg~(-1)), and high(4.88 g·kg~(-1)) doses. Intragastric administration was conducted for 5 weeks. Forelimb grip strength of rats in each group was recorded and analyzed. Masson staining and sirius red staining were used to evaluate pathological changes in skeletal muscle. Transmission electron microscopy(TEM) was used to observe autophagosomes and mitochondrial ultrastructure. Immunofluorescence was employed to detect the colocalization of microtubule-associated protein 1 light chain 3β(LC3B)-lysosome-associated membrane protein 1(LAMP1), as well as the expression of translocase of outer mitochondrial membrane 20(TOMM20). Immunohistochemistry was used to detect sequestosome 1(P62)protein expression. Western blot and RT-qPCR were used to analyze the expression levels of autophagic flux-related markers LC3B, P62, LAMP1, as well as mitochondrial function-related markers TOMM20 and mitofusin 2(MFN2)in skeletal muscle. The concentrations of serum inflammatory factors interleukin-1β(IL-1β) and interferon-γ(IFN-γ) were measured by ELISA to explore changes in the inflammatory environment. Compared with those in the blank group, Masson staining and sirius red staining of the gastrocnemius muscle in the model group showed increased collagen deposition and obvious fibrous hyperplasia. TEM revealed numerous autophagosomes in the cytoplasm of muscle cells, mitochondrial swelling, extensive cristae rupture and dissolution, matrix loss, and vacuolization. Immunofluorescence showed that the number of LC3B puncta and the LC3B-LAMP1 colocalization coefficient increased(P<0.01), while TOMM20 fluorescence intensity decreased(P<0.01). Immunohistochemistry showed increased P62 positive expression(P<0.01). Western blot and RT-qPCR results showed that the expression of TOMM20, MFN2, and P62 in the gastrocnemius muscle significantly decreased(P<0.01), while the expression of LC3B and LAMP1 was upregulated(P<0.01). Serum ELISA results showed that IL-1β and IFN-γ were significantly increased(P<0.01). After HQGZWWT intervention, the expression levels of TOMM20, P62, and MFN2 were significantly upregulated(P<0.01), while the expression of LC3B and LAMP1 was significantly downregulated(P<0.01). Electron microscopy showed improved mitochondrial morphology and reduced autophagosomes. The degree of fibrosis was significantly reduced(P<0.01). Inflammatory factors such as IL-1β and IFN-γ were significantly downregulated(P<0.01). In summary, HQGZWWT can ameliorate skeletal muscle injury in RA-associated sarcopenia by regulating mitochondrial quality control, the autophagy-lysosome flux, and inflammatory responses. This study provides new experimental evidence for the treatment of RA-associated sarcopenia with HQGZWWT and offers basic support for its better clinical application.