Original Articles
Haiying WANG, Caihua DING, Chunyu YANG, Yi CAO
Objective: To investigate the bone protective effects and underlying mechanisms of 900MHz radiofrequency radiation (RF) at different power densities (50, 150, and 450 μW/cm²) on an ovariectomy-induced osteoporosis mouse model. Methods: Sixty 3-month-old C57BL/6 female mice were randomly divided into Sham group (sham exposure), OVX group (ovariectomy), OVX + LRF group (OVX + 50 μW/cm2 RF), OVX + MRF group (OVX + 150 μW/cm2 RF), OVX + HRF group (OVX + 450 μW/cm2 RF), and OVX + E2 group (OVX + estradiol). Ovariectomized mice in the OVX + RF groups were exposed to RF of varying power densities for 4 hours daily. Ovariectomized mice in the OVX + E2 group received intramuscular injections of estradiol (0.04 mg/kg) every two days. After four weeks of intervention, Micro-CT, ELISA, RT-PCR, and immunohistochemistry were employed to analyze bone density, bone microstructure, serum bone metabolic markers, and the expression of related genes and proteins. Results: Compared with the Sham group, the OVX group showed significantly decreased bone mineral density (BMD) and bone microstructure indicators such as BV, BV/TV, Tb.Th, and Tb.N, significantly increased bone microstructure indicator Tb.Sp, significantly decreased serum estradiol, significantly increased serum CTX-I, TRACP-5b, BGP, and OPG, significantly increased Nfatc1 and Runx2 mRNAs, and significantly increased OPG and RANKL. Compared with the OVX group, the OVX + MRF group and OVX + E2 group exhibited significantly increased BMD, BV, BV/TV, Tb.Th, and Tb.N, significantly decreased Tb.Sp, significantly increased serum OPG, Runx2 mRNA, and OPG, and significantly decreased serum CTX-I, TRACP-5b, Nfatc1 mRNA, and RANKL. Compared with the OVX group, the OVX + LRF group showed significantly increased cortical bone BMD and Tb.Th, the OVX + HRF group showed significantly increased cortical bone BMD and serum CTX-I and TRACP-5b, and the OVX + MRF group showed significantly increased serum BGP. Among the three power densities, the 150 μW/cm2 RF showed the most significant effect. Conclusion: The 150 μw/cm2 900 MHz RF can counteract the abnormalities in serum bone metabolism biomarkers, the decrease in BMD, the degeneration of bone microstructure, and the increase in bone resorption caused by ovariectomy in mice.