Effects of estradiol on proliferation and metabolism of rabbit mandibular condylar cartilage cells in vitro

摘要

Objective To investigate the effects in vitro of 17 β-estradiol (E_2) on the proliferation and metabolism of rabbit mandibular condylar cartilage cells. Methods Chondrocytes were derived from neonatal rabbit mandibular condylar cartilage using a modified enzyme method. 17β-estradiol was added to the culture medium in a variety of concentrations. Cell growth and DNA, collagen, and proteoglycan synthesis were used as indicators of proliferation and differentiation of condylar chondrocytes. These were measured by cell number, ~3H-proline and ~(35)S-incorporation, respectively. Results E_2 increased cell number and ~3H-thymidine incorporation at 10~(-8) to 10~(-10) mol/L, and 10~(-8) to 10~(-11) mol/L in a dose-dependent manner, peaking at 10~(-8) mol/L and 10~(-9) mol/L, respectively. However, further increase in the concentration of estradiol caused inhibition of both cell number and ~3H-thymidine incorporation, and this was significant at 10~(-6) mol/L. The effect of E_2 on proteglycan synthesis was similar; the maximum stimulating effect was at 10~(-8) mol/L, and inhibition was significant at 10~(-6) mol/L. There was no obvious stimulatory effect of E_2 on ~3H-thymidine incorporation observed. Conclusions Estradiol affects condylar chondrocyte cell growth, DNA, and proteoglycan synthesis in a biphasic manner depending on its concentration. This indicates that estrogen may be important in the proliferation and differentiation of mandibular condylar chondrocytes, and could be relevant to some aspects of certain tempormandibular joint diseases by modulating the function of the chondrocytes.