Objective: To study the expression characteristics and biological significance of nuclear factor NF-kappaB p50 and NF-kappaB p65 in osteoporosis development. Adult mice were ovariectomized as models of experimental osteoporosis. In this way, we can explore the molecular mechanism of osteoporosis and understand the significance during the morbility of osteoporosis.
Methods: Four-month female BALB/c mice were randomly divided into ovariectomized group and sham-operated group. 12 weeks after surgery, the mice were sacrificed after the measurement of bone mineral density (BMD). The NF-kappaB level in bone tissue were determined by immunohistochemistry and in situ hybridization techniques.
Results: Compared with the sham-operated group, bone density, rarefaction of trabecula and the number of osteoblast decreased in the ovariectomized group, while the number of osteoclast increased in the ovariectomized group. The immunohistochemistry showed that NF-kappaB expressed in both groups. It mainly localized in the cytoplasm of osteoblast, osteocytes and marrow stroma cell. The expression level in the ovariectomized group was higher than that in the sham-operated group and was negatively correlated with the BMD (P < 0.01 or P < 0.05). In situ hybridization demonstrated that the expression levels of NF-kappaB 50mRNA and NF-kappaB 65mRNA in ovariectomized group were significantly higher than that of the sham-operated group (P < 0.05).
Conclusion: The expression level of NF-kappaB significantly increased in the bone tissue of ovariectomized mice, and its abnormal expression was significantly correlated with BMD.