| Objective To explore the mechanism of intestinal homeostasis in bone loss in ovariectomized (OVX) rats and the preventive and therapeutic effects of kidney tonifying and spleen strengthening formula.Methods A cohort of eighteen 4-month-old female Sprague-Dawley (SD) rats, which were nulliparous, were randomly assigned into three groups: a sham-operated control group (SHAM), an ovariectomized group (OVX), and a group treated with the kidney- tonifying and spleen-strengthening prescription (BSJP), with each group comprising six subjects. Following a 5-day post-operative recovery period, the SHAM and OVX groups were administered saline via gavage, whereas the BSJP group received the prescribed formulation via the same route for a duration of 12 weeks prior to sample collection. Analyses included Micro-CT imaging of the femur to evaluate bone density and microarchitecture, histological examination with hematoxylin and eosin (HE) staining of the small intestine and femur tissues, enumeration of osteoclasts through tartrate-resistant acid phosphatase (TRAP) staining, and Western Blot analyses to quantify the expression levels of the intestinal barrier protein Claudin-3 (Cldn3), pro-inflammatory cytokines TNF-α and IL17A, chemokines CCL20 and CXCR3, and osteoclast-associated proteins C-FOS, DC-STAMP, and Cathepsin K (CTSK) in both the intestinal and bone tissues. Results Comparative analysis between the OVX and BSJP groups revealed a significant thickening of the intestinal wall, attenuation of damage to the villous architecture of the small intestine, and a reduction in osteoclastic activity within the femur in the BSJP group. Micro-CT scans demonstrated a notable increment in bone mineral density (BMD) . Elevated expression of the intestinal barrier protein Cldn3 was observed in conjunction with a decrease in the levels of pro-inflammatory markers TNF-α, IL17A and chemokines CCL20, CXCR3 as well as a reduction in osteoclast-associated proteins C-FOS, DC-STAMP, and CTSK. Conclusion Osteoporosis in ovariectomized (OVX) rats stems from a dysregulation of gastrointestinal homeostasis. The administration of the kidney-tonifying and spleen-strengthening formula appears to restore this balance, thereby ameliorating the bone loss associated with OVX. |