| Objective To investigate the joint effect of schisandrin B and treadmill exercise on bone microstructure in senile osteoporosis (SOP) rats based on silent mating type information regulation 2 homolog 1 (SIRT1)/peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α)/nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway. Methods Sixty 24-month SD rats were randomly assigned into SOP group, schisandrin B group, exercise group, schisandrin B+exercise group, and schisandrin B+exercise+SIRT1 inhibitor (EX-527) group, with 12 rats in each group. Twelve 6-month rats were designated as controls (youth group). ELISA was used to measure serum type I collagen N-terminal telopeptide (NTX-I), procollagen I C-terminal propeptide (PICP), osteocalcin, and alkaline phosphatase (ALP). Dual energy X-ray absorptiometry was used to measure the bone mineral density of right femur. The tibia was scanned with a micro-CT scanner, and bone parameters were analyzed. The colorimetric method was used to detect malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD) in the left femur. Western blotting was used to detect SIRT1, PGC-1α, Nrf2, and heme oxygenase-1 (HO-1) proteins in the left femur. Results Compared to SOP group, schisandra B group, exercise group, and schisandra B+exercise group had lower serum NTX-I, right tibial trabecular space, left femoral MDA, and higher serum PICP, osteocalcin, ALP, right femoral bone mineral density, right tibial bone volume fraction, trabecular number, left femoral GSH-Px, SOD, and the SIRT1, PGC-1α, Nrf2, HO-1 proteins, and the trend of Schisandrin B+exercise group was the most clear (P<0.05). EX-527 reversed the inhibitory effect of joint effect of schisandrin B and treadmill exercise on oxidative stress and its improvement on bone microstructure in SOP rats. Conclusion The joint use of schisandrin B and treadmill exercise may inhibit oxidative stress and improve bone microstructure in SOP rats by activating SIRT1/PGC-1α/Nrf2 pathway. |