Lehmann Petra, Rank Petra, Hallfeldt Klaus L J, Krebs Bjarne, Gärtner Roland
Medizinische Klinik der Universität München, Campus Innenstadt, 80336 München, Germany.
Biol Trace Elem Res. 2006 Aug;112(2):119-30. doi: 10.1385/BTER:112:2:119.
Apoptosis of thyroid follicular cells is induced by high doses of iodide, epidermal growth factor (EGF), transforming growth factor-beta (TGF-beta), as well as H2O2 and might be attenuated by antioxidants. Therefore, we examined the apoptotic index induced by these substances in selenium-treated vs untreated human thyroid follicular cells. Reconstituted human thyroid follicles were incubated with sodium selenite (10 or 100 nM) for 72 h; controls received none. The follicles were then distributed to 24-well plates and incubated with potassium iodide (5, 10, or 20 nM), EGF (5 ng/mL), TGF-beta (5 ng/mL), or H2O2 (100 muM). Apoptosis was determined by a mitochondrial potential assay and the number of apoptotic cells counted by two independent, experienced technicians and the glutathione peroxidase (GPx) activity was determined. Asignificant increase of apoptic cells was obtained in control thyroid follicles treated with iodine (5, 10, or 20 microM), thyroidstimulating hormone (TSH) 1, or 10 mU/mL in combination with 5 and 10 microM iodine, EGF (5 ng/mL) and TGF-beta (5 ng/mL), or H2O2 (100 microM) (p < 0.001). In contrast, in thyroid follicles preincubated with 10 or 100 nM sodium selenite, the apoptototic index was identical to the basal rate. In H2O2-treated follicles, the apoptotic index was still significantly elevated but 50% lower compared to control cells. The GPx activity increased from 1.4 +/- 0.2 to 2.25 +/- 0.4 mU/microg DNA with 10 nMselenite and 2.6 + 0.4 mU/microg DNA with 100 nM selenite. Sodium selenite might increase the antioxidative potential in human thyroid follicles in vitro and therefore diminish the apoptosis induced by TGF-beta, EGF, iodide, and even H2O2.
高剂量碘化物、表皮生长因子（EGF）、转化生长因子-β（TGF-β）以及过氧化氢可诱导甲状腺滤泡细胞凋亡，而抗氧化剂可能会减弱这种凋亡。因此，我们检测了这些物质在硒处理和未处理的人甲状腺滤泡细胞中诱导的凋亡指数。将重组人甲状腺滤泡与亚硒酸钠（10或100 nM）孵育72小时；对照组不添加任何物质。然后将滤泡分到24孔板中，与碘化钾（5、10或20 nM）、EGF（5 ng/mL）、TGF-β（5 ng/mL）或过氧化氢（100 μM）一起孵育。通过线粒体电位测定法确定凋亡情况，由两名独立且经验丰富的技术人员计数凋亡细胞数量，并测定谷胱甘肽过氧化物酶（GPx）活性。在用碘（5、10或20 μM）、促甲状腺激素（TSH）1或10 mU/mL联合5和10 μM碘、EGF（5 ng/mL）和TGF-β（5 ng/mL）或过氧化氢（100 μM）处理的对照甲状腺滤泡中，凋亡细胞显著增加（p < 0.001）。相比之下，在预先用10或100 nM亚硒酸钠孵育的甲状腺滤泡中，凋亡指数与基础水平相同。在过氧化氢处理的滤泡中，凋亡指数仍显著升高，但与对照细胞相比降低了50%。GPx活性从1.4±0.2 mU/μg DNA增加到10 nM亚硒酸钠时的2.25±0.4 mU/μg DNA以及100 nM亚硒酸钠时的2.6±0.4 mU/μg DNA。亚硒酸钠可能会增加体外人甲状腺滤泡的抗氧化能力，从而减少由TGF-β、EGF、碘化物甚至过氧化氢诱导的凋亡。
