Effects of 17beta-estradiol and progesterone on the expression of matrix metalloproteinases and tissue inhibitors of metalloproteinases in rat osteoblasts.

OBJECTIVE: To study the expression of matrix metalloproteinases (MMP) and tissue inhibitors of metalloproteinases (TIMP) in the osteoblasts of SD rats and to assess the change of MMP-2 and TIMP-1 induced by 17beta-estradiol (E2) and progesterone (P), for the purpose of understanding the role of MMP-2 and TIMP-1 in bone resorption. METHODS: The expression and localization of the MMP-2 in cultured rat osteoblasts were observed immunohistochemically, and MMP-2 and TIMP-1 mRNA expression assayed by reverse transcriptase-polymerase chain reaction (RT-PCR) after the cells were treated with E2 and P at varied concentrations. RESULTS: MMP-2 protein expression was observed in cultured rat osteoblats, which was inhibited by E2 treatment. The expression of MMP-2 mRNA decreased as doses of E2 and P increased but TIMP-1 underwent no obvious changes. CONCLUSION: E2 and P can promote the bone formation and slow down the processes of bone matrix degradation and bone resorption by inhibiting the action of MMP-2 in the osteoblasts, and P has the same important effect as estrogen has in the treatment of postmenopausal osteoporosis.