Effects of excessive iodine and casein on histomorphalogy and ultrastructure of mouse thyroid / 中国地方病学杂志

ABSTRACT

Objective To observe the effects of casein and excessive iodine on histomorphalogY and ultrastructure of mouse thymicL Methods Based on 2 × 3 factorial design,the experimental mice were divided into 6 groupg Animal models were estabhshed by feeding the mice with different levels of iodine water and casein food.The levels of iodine were 50,600 μg/L in drinking water and 0(Ⅰ),10%(Ⅱ),20%(Ⅲ)of casein in food respectively.After 12 months,the thyroid weight was measured and the morphology of thyroid was observed under optical and electron microscope.Results Factorial analysis showed that iodine factors obviously affected the thyroid absolute and relative weiights of mice(F=16.23,9.47,P＜0.01),and there was interaction between casein and iodine(F=5.29,4.68,P＜0.01 or＜0.05).Compared wiht 150Ⅰ[(5.91±0.82)rag,(117.0±22.2)mg/kg]and 50Ⅲ[(4.90±0.63)rag,(106.1±13.3)mg/kg]groups.thyroid absolute and relative weights of the mice increased in 600 Ⅰ[(7.60±2.40)mg,(143.3±43.2)mg/kg]and 600Ⅲ[(8.63±1.88)mg,(166.2±39.4)mg/kg]groups(P＜0.05 or＜0.01),respectively.But compared with 600 Ⅰ and 600Ⅲ groups.they were reduced obviously in 600Ⅱ[(5.76±1.13)mg,(109.8±16.5)mg/kg]group(P＜0.05 or＜O.01).Colloid goiter,lymphocyte infiltration were found,some of the follicles epithelial cells appeared active under light and electron microscope in iodine excels group,which,however,decreased obviously along with the increase of casein dose.Conclusions Long-term excessive iodine may cause colloid goiter and inflammation injury of mice,possibly leading the development of thyroiditis in mice,which may be partly reduced by casein.