Bone fracture is an important factor affecting the life quality and mortality of elderly individuals, and its pathogenesis involves the imbalance of bone metabolism maintained by osteoblasts (OB) and osteoclasts (OC). ⁹⁹Tc-MDP is a drug for the targeted treatment of osteoporosis. While it can directly inhibit OC activity, there have been no in vivo data on its ability to induce OB activity.

This study aims to evaluate the effect of ⁹⁹Tc-MDP on osteogenesis in the treatment of osteoporosis.

In this study, a rat model of osteoporosis after ovariectomy were constructed to reflect the early process of osteoporosis formation, including calcium loss and bone mineral density decrease. Then, experimental rats were randomly divided into 4 groups, i.e., negative control group, model control group, ⁹⁹Tc-MDP treatment group and zoledronic acid treatment group, with 5 rats in each group (a total of 20 rats). Subsequently, the dynamic changes of osteoblast indexes such as blood calcium level and blood phosphorus content, after ⁹⁹Tc-MDP treatment were detected at the cellular, metabolic, and genetic levels to evaluate the effect of ⁹⁹Tc-MDP on osteogenesis in the treatment of osteoporosis.

Experimental comparison results demonstrate that ⁹⁹Tc-MDP effectively inhibits the osteoporosis process and reverses bone mineral density loss by inducing OB activity, achieving the suppression of bone decline at 4 weeks and returning to the preoperative level at 8 weeks. Although the OB activity induced by ⁹⁹Tc-MDP is altered to similar levels in OB cells of normal rats, but there is no significant change in the expression of major bone-related genes. The multifactor analysis results suggest that IL-6 can be the key factor and monitoring index.

⁹⁹Tc-MDP can stimulate OB activity as a powerful supplement to inhibiting OC activity, which is beneficial to the maintenance of OB/OC homeostasis.