Effects of Gushukang Granules on the expression of myogenic and osteogenic factors in the muscles and bones of sarcopenic osteoporosis rats

Abstract

BACKGROUND: In sarcopenic osteoporosis, muscle loss and osteoporosis often coexist, leading to a significant increase in the risk of falls and fractures. Gushukang Granules are clinically used for the treatment of osteoporosis; however, the mechanism of action on myogenic and osteogenic factors in muscle and bone remains unclear. OBJECTIVE: To investigate the effects of Gushukang Granules on myogenic and osteogenic factors in the muscles and bones of rats. METHODS: Thirty-six healthy Sprague-Dawley rats were randomly divided into control, model, and Gushukang groups (n=12 per group). Osteoporosis was induced in the latter two groups by ovariectomy. Four weeks after surgery, the Gushukang group received 1.05 mL/kg Gushukang Granules solution by gavage, while the other groups received an equal volume of saline, once daily for 12 weeks. General conditions were observed. Hematoxylin-eosin staining was used to assess morphological changes in muscle and bone tissues. RT-qPCR was performed to detect mRNA expression of interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha) in muscle, and osteocalcin (OCN) and insulin-like growth factor 1 (IGF-1) in bone. Immunohistochemistry was used to observe the expression of IL-6, TNF-alpha, IGF-1, and OCN in muscle and bone tissues. Western blot was used to detect protein expression levels of these factors. RESULTS AND CONCLUSION: Compared with the control group, the model group exhibited typical sarcopenic osteoporosis phenotype: muscle fibers were sparse, disordered, and atrophic; bone trabeculae were reduced, sparse, and disconnected. mRNA and protein expression of IL-6 and TNF-alpha were significantly increased (P < 0.01), while IGF-1 and OCN were significantly decreased (P < 0.01). Compared with the model group, the Gushukang group showed significant improvement: muscle fiber arrangement became more orderly with interstitial fibrosis; bone trabeculae increased and connectivity improved (though still loose). IL-6 and TNF-alpha expression were significantly decreased (P < 0.01), while IGF-1 and OCN were significantly increased (P < 0.01). Western blot results were consistent with immunohistochemistry. These findings suggest that Gushukang Granules can improve muscle atrophy and bone trabecular thinning in ovariectomized rats by downregulating the abnormal high expression of IL-6 and TNF-alpha, and upregulating IGF-1 and OCN, possibly through regulating muscle-bone crosstalk signaling pathways and balancing inflammatory and growth factor levels, providing experimental support for the clinical treatment of sarcopenic osteoporosis.

1. Introduction

Sarcopenic osteoporosis is a condition characterized by the coexistence of muscle loss and osteoporosis, predominantly affecting the elderly. The combination of these two conditions significantly increases the risk of falls and fractures, profoundly impacting patients' health [1]. In traditional Chinese medicine (TCM), the kidney governs bones and produces marrow, serving as the foundation of innate constitution; kidney deficiency leads to marrow depletion and bone weakness, termed 'bone atrophy'. The spleen governs muscles, serving as the foundation of acquired constitution; spleen deficiency impairs the transformation and transportation of qi and blood, failing to nourish muscles, resulting in 'muscle atrophy' [2]. Based on the TCM theory of 'innate and acquired foundations' and the spleen-kidney relationship, our research group has proposed the key pathogenesis of 'bone deficiency and muscle wasting' in sarcopenic osteoporosis, clarifying the pathological process: 'bones and muscles mutually nourish and constrain; tendons and muscles lie beneath and moisten the marrow; if bone is deficient, muscles do not attach to bone and become thin; if muscles are deficient, they cannot nourish bone, leading to bone withering'. Therefore, supplementing the 'innate' and nourishing the 'acquired', i.e., tonifying the kidney and strengthening the spleen, is an important therapeutic approach to achieve 'strong bones and abundant muscles'.

The interaction between muscle and bone involves various cytokines and growth factors, such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), insulin-like growth factor 1 (IGF-1), and osteocalcin (OCN), which play crucial roles in maintaining muscle and bone health [3-5]. IL-6 and TNF-alpha are inflammatory cytokines that play dual roles in the pathogenesis of sarcopenic osteoporosis: on one hand, they may promote bone loss; on the other hand, they may exacerbate sarcopenia by affecting muscle mass [6]. IGF-1, as an important growth factor, has been shown to promote the development and maintenance of muscle and bone; its deficiency may lead to muscle and bone degeneration [7]. Osteocalcin, a bone matrix protein, participates in bone formation and remodeling. This study aims to investigate the effects of Gushukang Granules on the expression of these myogenic and osteogenic factors in a rat model of sarcopenic osteoporosis, providing experimental evidence for its clinical application.