甲状腺刺激抗体对甲状腺细胞过氧化物酶活性影响

Effect of thyroid stimulating antibody on thyroid peroxidase activity in cultured thyrocytes

目的 探讨甲状腺刺激抗体 (TSAb)对培养的甲状腺细胞甲状腺过氧化物酶 (TPO)活性及其信号传导途径的影响。方法 应用改良愈创木酚法观察TSAb对原代培养人甲状腺细胞TPO活性的影响。结果 4mg/mlTSAb作用 48h可使甲状腺细胞TPO活性达对照的 3 60 % ;蛋白激酶A(PKA)抑制剂使TSAb作用的TPO活性增加减少近 79.2 % (P <0 .0 1) ,而胞内Ca2 + 鳌合剂及木黄酮对TPO活性无明显影响。结论 TSAb通过激活cAMP/PKA途径导致TPO活性增加可能是TSAb致Graves病的主要机制之一。

Objective To investigate the effects of thyroid stimulating antibody (TSAb) on the thyroid peroxidase (TPO) activity and its signal transduction pathways in cultured thyrocytes. Methods The TPO activity in primary cultured human thyrocytes was determined by amended guaiacol oxidation assay. At the same time, inhibitors of signal transduction were applied and the roles of cAMP/protein kinase A (PKA), phosphatidylinositol (PIP 2)/Ca 2+and tyrosine protein kinase (TPK) pathway on the TPO activity in cultured thyrocytes were observed. Results TSAb significantly enhanced the TPO activity in cultured thyrocytes, and the peak of TPO activity (360% of controls) reached with 4 mg/ml TSAb for 48 h. Addition of PKA inhibitor for blocking cAMP/PKA pathway decreased TPO activity by 79.2% (P<0.01); while addition of BAPTA-AM for scavenging intracellular Ca 2+or TPK inhibitor genistein, there was no evident change in TPO activity. Conclusion TSAb is capable of increasing TPO activity in cultured thyrocytes by cAMP/PKA pathway which seems to be an important mechanism in the pathogenesis of Graves′ disease.