锌中毒对雏鸭免疫系统结构及其功能影响的研究

目的 :　探讨锌中毒对免疫器官结构和功能的影响及其机制。方法 :　通过建立雏鸭锌中毒模型 ,应用免疫组织病理学方法检测雏鸭胸腺、腔上囊、脾脏绝对重量及指数、生长周期、外周血 T淋巴细胞 ANAE+ 阳性率 ,红细胞 C3b、CIC花环率以及观察免疫器官显微、超微病理组织学变化。结果 :　 (1 )锌中毒组 (ZT)体重 2 1日龄以后极显著低于锌对照组 (ZC,P<0 .0 1 )。 (2 )ZT胸腺、腔上囊 2 w龄以后、脾脏 3 w龄以后其绝对重量均极显著低于 ZC(P<0 .0 1 )。 (3 ) ZT胸腺、腔上囊、脾脏细胞周期的静止期细胞明显增高 ,而增殖期细胞下降 ,与 ZC比较差异极显著 (P<0 .0 1 )。(4 ) ZT2～ 4w龄外周血 T淋巴细胞 ANAE+阳性检测率极显著低于 ZC(P<0 .0 1 )。 (5 )显微镜下 ZT胸腺、腔上囊、脾脏淋巴细胞数量显著减少 ,排列稀疏 ;电镜下淋巴细胞线粒体受损 ,网状细胞均含有大量各级溶酶体、吞噬体。 (6) ZT红细胞 C3b RR花环率极显著低于 ZC组 (P<0 .0 1 ) ,而红细胞 CIC花环率却极显著高于 ZC(P<0 .0 1 )。结论 :　锌中毒严重抑制雏鸭免疫器官的发育 ,造成明显的病理损伤 ,导致细胞、体液、红细胞免疫功能下降

EFFECTS OF ZINC TOXICITY ON THE STRUCTURE AND FUNCTION OF IMMUNE SYSTEM IN DUCKLINGS

Objective: To investigate the influence and mechanism of zinc toxicity on the stucture and function of immune organs in ducks. Methods: By establishing the pathological model of zinc toxicity in ducks, some immunological methods, light and electron microscopes were used to check the changes in the stucture and function of immune system. Results: (1) The body weight of ZT group was significantly lower than that of ZC group after 3 weeks (P<0.01). (2) Weights of thymus, the bursa of Fabricius after 2 weeks and that of spleen after 3 weeks were decresed significantly in ZT ducks. (3) In 4 weeks, the G 0/G 1 phases of cell cycle of thymus, bursa of Fabricius and spleen were significantly higher and S, G 2+M phases lower in ZT group than those in ZC group. (4) In ZT grop, ANAE + positive rates of T lymphocytes in peripheral blood in 2 4 weeks were significantly lower than those of ZC group (P<0.01). (5) Compared with controls, in ZT ducks the counts of lymphocyte reduced significantly and lymphocytes lined loosly in the thymus, bursa of Fabricius and spleen histopatologically. The ultrastructural observation showed that the mitochondriae in lymphocytes of the thymus, bursa of Fabricius and spleen were damaged and reticular cells consisted of many primary and secondary lysosomes as well as phagocytes in ZT ducks. (6) In comparison with the control, the erythocyte C 3bR rosette rates were significantly lower and the erythrocyte ICR rosette rates were significantly higher in ZT ducks (P<0.01). Conclusion: Zinc toxicity greatly hindered the development of immune organs, caused obvious pathological injury of immune organs, and weakened the funcion of humoral, cellular and erythrocyte immunity.