Sintered dicalcium pyrophosphate decreases bone turnover rate in osteoporotic rat: A study on serum biochemical bone turnover markers

Sintered dicalcium pyrophosphate (SDCP) is a synthetic pyrophosphate analog that could be utilized in the treatment for osteoporosis. In this study, an ovariectomized (OVX) Wistar rat model is applied to evaluate the effects of SDCP on biochemical bone turnover markers relative to its effects on bone mass. OVX rats were treated with SDCP in the dose of 0.75 mg/kg daily for continued 13 weeks. Rats were sacrificed after predetermined periods; serum levels of bone turnover markers were evaluated. Parallel histological evaluation and bone ashes of the long bones of four limbs were performed. Results showed that the serum level of bone resorption marker (type I collagen fragments) for rats treated with SDCP decreased, and the levels of bone formation markers (alkaline phosphatase [ALP], osteocalcin and osteopontin) also decreased significantly. These findings reveal the bone turnover rate decreased. Histological examinations of distal femoral metaphysis revealed the OVX rats ingested with SDCP restored the architectures of trabecular bone and decreased the porosity. This finding was consistent with the increase in serum tartrate-resistant acid phosphatase 5b level, an indicator that represents the number of osteoclast, which indicates an increase of bony tissues. The analyses of limbs bone ashes showed a significant increase in bone mineral contents. This study indicates that the SDCP inhibits the bone resorption rate to restore the bone mass in the OVX rats that could be applied in clinic in the future.