Effect of fluoride on the expression of bcl-2 and Bax proteins in chondrocyte / 中国地方病学杂志

ABSTRACT

Objective To study the effect of fluoride on the expression of bcl-2 and Bax in chondrocyte in vitro, and investigate the mechanism of action of chondrocyte apoptosis induced by fluoride. Methods Articular chondrocytes of neonate rat were cultured in vitro and treated with 0(control),5,20,40 mg/L of fluoride,respectively, for 10 days. Then observed the u]trastructure of chondrocytes under eletronicmicroscope, and tested the expression of bcl-2 and Bax in chondrocyte in different groups by Western blotting. Results Abundant rough endoplasmic reticulums (RERs) and complete structure of mitochondria membranes were presented in globular chondrocytes in the control group and 5 mg/L group; but more lipid droplets and vacuoles were seen in the cytoplasm, and the structure of intracellular membranes became incomplete, and some shrieked chromatin and pyknosis were seen in the chondrocytes of the 20,40 mg/L groups. The expression of bcl-2 markedly decreased in 20 mg/L group(0.626 ± 0.042) and 40 mg/L group(0.531± 0.039) compared to the control group(0.876 ± 0.035,all P ＜ 0.01 ). And the expression of Bax significantly increased in 20 mg/L group(0.966 ± 0.047) and 40 mg/Lgroup ( 1 .289 ± 0.156) compared to the control group(0.642 ± 0.050, all P ＜ 0.01). But there was no statistical significant difference of the expression of bcl-2 or Bax between 5 mg/L group(0.885 ± 0.065,0.657 ± 0.045) and control group (all P ＞ 0.05 ). However there were statistical differences of expressions of bcl-2 and Bax between 20 and 40 mg/L groups(all P ＜ 0.01 ). Conclusions Twenty and 40 mg/L fluoride can cause damage to the ultrastructure of chondrocyte, and fluoride possibly promotes chondrocyte apoptosis by reducing the expression of antiapoptotic factor bcl-2 and increasing the expression of Bax.