氟对原代培养猪甲状腺细胞功能的影响

Effect of fluoride on thyroid functioning in primary porcine thyrocyte

目的探讨氟对原代培养甲状腺细胞功能的影响。方法用猪甲状腺细胞，采用原代培养方法，按染氟（NaF）剂量不同分为：0（对照组）、40、80、160mg／L组。染氟48h后，采用噻唑蓝（MTT）法测定细胞存活率，改良愈创木酚法测定甲状腺过氧化物酶（TPO）活性，放射免疫法测定甲状腺素（T4）水平。结果甲状腺细胞培养48h后，细胞贴壁，多呈六边形，呈聚集性趋势生长，并可见典型的滤泡结构。甲状腺细胞染氟培养48h后，细胞存活率组间比较差异有统计学意义（F=1．49．092，P〈0．05）；40mg／L组细胞存活率为（96．04±2．08）％，与对照组（100％）比较，差异无统计学意义（t=2．157，P〉0．05）；80、160mg/L组细胞存活率分别为（86．59±1．79）％、（70．12±1．49）％，与对照组比较，差异有统计学意义（f值分别为7．621、17．697，P〈0．05）。甲状腺细胞T4水平随着染氟剂量的升高而明显降低[（44．940±8．212）、（31．442±4．384）、（22．742±4．504）、（15．193±1．633）nmol／L]，组间比较差异有统计学意义（F=978．255，P〈0．05）。甲状腺细胞TPO活性也随着染氟剂量的升高而明显降低[（3．103±0．090）、（1．944±0．025）、（1．361±0．008）、（0．668±0．026）U／L]，组间比较差异有统计学意义（F=1563．864，P〈0．05）。TPO活性与染氟剂量呈负相关（r=-0．955，P〈0．05）。结论氟可通过降低T4水平而影响甲状腺功能，其发生机制可能是通过诱导细胞凋亡，降低细胞存活率和抑制TPO活性有关。

Objective To approach the effect of fluoride on thyroid function in primary porcine thyrocytes. Methods Porcine thyrocytes were cultured in sodium fluoride to establish the experimental model and then divided according to the final concentration of NaF into 0（control group）, 40, 80 and 160 mg/L groups. Exposed to NaF for 48 h, cell survival ratio was measured with methyl thiazolyl tetrazolium （MTT） method and the thyroid peroxidase（TPO） activity was measured with upgrade guaiacol method. Radio-immunoassay was used to detect thyroxine level （T4）. Results These adherent thyroid cells cultured for 48 h aggregated to grow in shape of hexagonal and typically follicular structure. Cell survival ratio, significant different between the groups （F= 149.092, P〈 0.05） being （96.04 ± 2.08）% in the 40 mg/L group, not statistically significant from the control group （100%）（t = 2.157, P 〉 0.05）. Meanwhile, it was（86.59 ± 1.79）% and （70.12 ± 1.49）% in the 80 mg/L and 160 mg/L group, having statistical significance （t = 7.621, 17.697, P 〈 0.05）; With the increasing dose of fluoride, level of T4 obviously lowered[ （3.103 ± 0.090）, （1.944 ± 0.025）, （1.361 ± 0.008）, （0.668 ± 0.026）U/L] and statistical significance was seen between the groups（F= 1563.864, P〈 0.05）. The TPO activity had a negative correlation with the the dose of fluoride （r = - 0.955 ,P 〈 0.05）. Conclusions ： Fluoride affects the thyroid function through down-regulating level of T4, whose mechanism is decreasing cell survival ratio and inhibiting TPO activity by inducing apoptosis.