| Objective To explore the protective mechanism of tonifying kidney and strengthening spleen decoction in disuse osteoporosis (DOP) rats through modulating the PI3K/AKT signaling pathway. Methods Forty-eight 2-month-old male SD rats were randomly divided into four groups: control, model, tonifying kidney and strengthening spleen decoction, and Western medicine (Fosamax) group, with 12 rats in each group. Rats in the model and drug group were subjected to tail suspension for DOP modeling for 8 weeks. Rats in the control and model group were gavaged with ultrapure water. Rats in the other two groups received respective drug gavage. After intervention, blood was collected from the abdominal aorta. Serum levels of ALP and TRACP were measured using ELISA. Pathological changes in the distal right femur were assessed using HE staining. Trabecular morphology, BMD, BV/TV, Tb.Th, and Tb.Sp were examined with micro-CT. Protein expressions of PI3K, p-PI3K, AKT, and p-AKT in the right femur were analyzed with Western blotting. mRNA expressions of PI3K and AKT were measured with RT-qPCR. Results Compared with the control group, the model group showed higher TRACP and Tb.Sp but lower ALP, BMD, BV/TV, and Tb.Th, and reduced expression of PI3K/AKT signaling pathway-related proteins and mRNA. HE staining and micro-CT revealed decreased new trabeculae, thinner trabeculae, larger spacing, smaller area, and sparse and fractured bone tissue in the model group. Compared with the model group, tonifying kidney and strengthening spleen decoction and Western medicine groups had lower TRACP and Tb.Sp, higher ALP, BMD, BV/TV, and Tb.Th, and increased expression of PI3K/AKT signaling pathway-related proteins and mRNA. HE staining and micro-CT indicated improved bone tissue structure. Conclusion Tonifying kidney and strengthening spleen decoction may enhance bone microstructure in DOP rats by modulating the PI3K/AKT signaling pathway, offering a potential preventive and therapeutic approach for DOP. |