丙硫氧嘧啶致甲状腺组织增生的时效关系研究

目的初步建立以染毒(PTU)为模型的甲状腺激素干扰物体内短期甄别实验系统。方法PTU(5mg/kgbw)灌胃染毒,分别设丙硫氧嘧啶染毒3、6、9、12天实验组及溶剂对照组,每组10只大鼠,在染毒期满后处死动物,取血清,用全自动化学发光法测量TT3,TT4和TSH,同时观察甲状腺组织病理改变,PAS染色观察胶质的改变,免疫组化法和Western-blot检测增殖细胞核抗原(PCNA)的表达。结果与对照组相比,染毒3天组,TT3开始出现显著的降低(P<0.05),6、9、12天组,TT3、TT4浓度均显著降低,并伴TSH浓度显著升高(P<0.05)。甲状腺脏器系数在6、9、12天组均显著高于对照组(P<0.05)。组织学观察发现3天组甲状腺滤泡上皮复层化;6天组弥漫性增生,大量增生斑、实心芽形成(P<0.05);9天组纤维母细胞和毛细血管内皮细胞大量增生,大量实心继发滤泡形成;12天组有大量的空心继发滤泡形成。PAS染色显示,3、6、9天组的甲状腺滤泡胶质染色弱阳性,12天组甲状腺滤泡胶质染色阴性。免疫组织化学检测的PCNA标记指数和Western-blot检测的PCNA/β-actin的相对值随时间变化的规律完全一致,即3天组开始显著增加(P<0.05);而6天组达到高峰(P<0.05);9天组开始减少(P<0.05);12天组与对照组相比则差异无显著性。结论初步确定甲状腺激素干扰物体内短期甄别实验实验观察终点为增生斑和实心芽,以及IHC检测的PCNA标记指数,最佳实验期为6天。

Time-effect study of propylthiouracil-induced thyroid gland hyperplasia

Objective Establish an effective method for in vivo short-time standardized discriminating system of thyroid hormone disruptors. Methods 4 experimental groups treated with PTU lavage for 3,6,9,12 days respectively and one dissolvent group for control. 10 rats in each group were sacrificed in due time with the serum being extracted and detected for T3,T4 and TSH by chemoluminescence. Histopathological changes were visualized by HE staining and changes in colloid were visualized by PAS staining. PCNA was detected by IHC and western-blotting.Results Comparing with control group,3-day treated started to show a decrease in serum concentration of TT3 (P<0.05),6-day,9-day and 12-day treated presented significant decreases in both concentration of TT3 and TT4,with a significant increase in TSH concentration (P<0.05). Viscera coefficients of thyroid gland were significantly greater than the controls in 6-day,9-day and 12-day treated groups (P<0.05). Histopathological observation found thyroid follicle epithelium stratification in 3-day sections,diffused hyperplasia,vast hyperplasia plaque and solid bubbles in 6-day sections(P<0.05),aggragated fibrilblasts and capillary endothelium hyperplasia and formation of large amount of solid sequential follicles in 9-day sections,mass hollow sequential follicles in 12-day sections. PAS staining showed weak positive in 3-day,6-day,9-day thyroid gland follicle colloid sections,and negative in 12-day sections. A coherent of changes with time was observed in PCNA labeling index and PCNA/β-actin ratio,i.e. starting to increase in 3-day group (P<0.05),reaching its peak at 6-day group (P<0.05) and decreasing from 9-day group (P<0.05),while no significant difference comparing with control in 12-day group. Conclusion hyperplastic patch ,solid bubble and PCNA labeling index detected by IHC used as early index for thyroid gland hyperplasia are stable and relient,and 6 day is optimization experiment phase.