Effect of fluoride on thyroid peroxidase activity and mRNA expression in porcine thyrocytes

Objective To approach the effect of fluoride on the expression of thyroid peroxidase(TPO)activity and TPO mRNA in primary porcine thyrocytes.Methods Purified cultured porcine thyrocytes waft made into sodium fluoride model,and were divided according to the final concentration of NaF into 0(control group),40,80,160 mg/L.After exposed to NaF for 48 h,the morphology of the porcine thyrocytes was investigated with acridine orange staining method,TPO activity was measured with upgrade guaiacol method and RT-PCR method was used to detect the ratio of TPO/β-actin.Results The major changes included apoptotic bodies and cell fragments in the 80,160 mg/L groups under phase contrast microscope.With the increasing dose of fluoride.TPO activity,being(3.103±0.090),(1.944±0.025),(1.361±0.008),(0.668±0.026)U/L,respectively,had obviously lowered with a statistical significance compared between the groups(F=1563.864,P＜0.05).The TPO activity had a negative correlation with the dose of fluoride(r=-0.955,P＜0.05).With the dose of fluoride increasing,the expression of TPO mRNA had obviously lowered,being(0.947±0.013),(0.634±0.018),(0.448±0.028)and (0.210±0.009)with a statistical significance in group comparison(F=2713.855,P＜0.05).Conclusion Fluoride affects the thyroid via inhibiting TPO activity and expression of TPO mRNA. Key words: Fluorides;  Cell,cultured;  Idoide pemxidase;  Gene expression