Advanced oxidation protein products (AOPPs) accelerate bone loss in rats

Purpose: Advanced oxidation protein products (AOPPs), markers of oxidative stress, can inhibit the proliferation and differentiation of rat osteoblast-like cells. Osteoporosis, a disease mainly results in bone loss, is closely related to oxidative stress. Whether AOPPs have any effect on bone loss in rats remains unclear. Therefore, the objective of our research is to investigate the effect of AOPPs on the bone loss of rats in vivo. Methods: Sprague-Dawley rats were divided into 4 groups (Control, RSA, AOPPs, AOPPs+SOD). PBS, rat serum albumin (RSA) and AOPPs were delivered daily by intraperitoneal injection with or without intragastric administration of superoxide dismutase (SOD) to the respective groups. Every 4 weeks, eight rats from each group were sacrificed and their blood, tibia and femur were harvested. The expression of osteocalcin and CTX in the serum was measured by ELISA, and the tibias were subjected to metaphyseal three-point bending and mu CT analysis. Results: AOPPs unregulated the serum level of osteocalcin and CTX compared to the Control and RSA groups. The measurement results of mu CT showed AOPPs had an effect on the decline of bone mass, while the three-point bending test revealed no significant differences in F-max, energy absorption and stiffness among the AOPPs and Control group throughout the investigation. No significant difference was found between the AOPPs and AOPPs+SOD group for any of the investigated parameters. Conclusion: This study demonstrated that AOPPs induced bone loss in rats. Therefore, we can infer AOPPs accelerate the development of osteoporosis in rats.