Shenqi Yanshen Decoction protects against renal and bone injury in chronic kidney disease-mineral and bone disorder with potential involvement of Wnt5a/RhoA/Pkn3 signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Shenqi Yanshen Decoction (SQYSD) is a traditional Chinese herbal formula that is used for treating chronic kidney disorders and kidney-related bone complications in the clinical setting under the traditional concept that "the kidney governs the bone". However, experimental evidence for its coordinated protective effects on renal and skeletal injury in chronic kidney disease-mineral and bone disorder (CKD-MBD) is limited. AIM OF THE STUDY: In this study, the therapeutic effects of SQYSD on renal dysfunction, mineral metabolism disorder, and bone injury in CKD-MBD were evaluated, and whether its actions are associated with the regulation of Wnt5a/RhoA/Pkn3-mediated activation of osteoclasts was investigated. MATERIALS AND METHODS: The chemical profile of SQYSD was characterized by UPLC-Q/TOF-MS, and the representative constituents were quantified by UPLC-MS/MS. A CKD-MBD mouse model was constructed by 5/6 nephrectomy combined with a low-calcium, high-phosphate diet. The mice were orally administered SQYSD for 10 weeks, with cinacalcet hydrochloride used as a clinically relevant positive control. Renal function, calcium-phosphate metabolism, and bone turnover markers were assessed biochemically. Renal and femoral pathological changes were evaluated by histological staining, transmission electron microscopy, and micro-computed tomography examinations. Transcriptomic analysis, RT-qPCR, Western blotting analysis, immunofluorescence analysis, and immunohistochemistry analysis were performed to investigate the mechanisms of action. RANKL-induced differentiation of osteoclasts in RAW264.7 cells, along with the overexpression of Wnt5a, was used for in vitro validation. RESULTS: By conducting UPLC-Q/TOF-MS, 71 phytochemicals were identified in SQYSD, and 12 representative constituents were quantified; among them, icariin, epimedin B, chlorogenic acid, and epimedin A were abundant components. In CKD-MBD mice, SQYSD improved body weight, decreased the levels of serum creatinine and blood urea nitrogen, corrected calcium-phosphate imbalance, and attenuated renal inflammatory infiltration, fibrosis, calcification, and ultrastructural injury. SQYSD also alleviated bone deterioration, as indicated by an improvement in bone mineral density, BV/TV, trabecular number and thickness, reduced trabecular separation, restored bone turnover markers, and a decrease in the accumulation of osteoclasts. Compared to cinacalcet, SQYSD showed broader protective effects on renal and skeletal lesions. Transcriptomic analysis indicated that SQYSD downregulated the Wnt signaling pathway, and subsequent validation suggested that these effects were associated, at least to some extent, with suppression of Wnt5a/RhoA/Pkn3-related signaling in renal and bone tissues. In vitro, SQYSD inhibited RANKL-induced differentiation of osteoclasts and formation of the F-actin ring, accompanied by the downregulation of Wnt5a, RhoA, Pkn3, and cytoskeleton-associated proteins. The overexpression of Wnt5a partially reversed the inhibitory effects of SQYSD on osteoclastogenesis. CONCLUSION: This study found that SQYSD exerts coordinated renal and skeletal protective effects in CKD-MBD, involving improvement of renal dysfunction, correction of mineral metabolic disorder, preservation of bone microarchitecture, and inhibition of the activation of osteoclasts. These effects may be partly associated with suppression of Wnt5a/RhoA/Pkn3-related signaling. The findings of this study provide pharmacological evidence supporting the traditional use of SQYSD in kidney-related bone disorders and suggest that it can serve as a complementary multi-target herbal intervention for CKD-MBD.