Expression of thyroid-stimulating hormone receptor in thyroid tissue of lactating rats / 中华地方病学杂志

ABSTRACT

Objective To observe the expressions of thyroid-stimulating hormone receptor (TSHR) protein and mRNA in thyroid gland of lactating rats.Methods Eighty adult Wistar rats (60 females and 20 males),weighting 210-250 g were selected.The 60 female Wistar rats were divided into 6 groups according to their body weight by means of random number tablenormal non-pregnant group,lactating for 5,10,15 and 20 days groups and weaning for 5 days group,10 rats in each group.All rats were fed with conventional fodder and tap water freely,and the rats of lactating groups except the normal non-pregnant group cohabited with male rats (3 ∶ 1).Then all rats were killed on the 5th,10th,15th and 20th day after lactation and on the 5th day after weaning to get thyroid tissues.The expressions of TSHR protein and mRNA were determined by immunohistochemical staining and realtime quantitative PCR.Results TSHR protein was expressed in cytoplasm and membrane of rat thyroid follicular cells.The expression of TSHR protein in thyroid gland was significant different statistically between groups (x2 =11.227,P ＜ 0.05); the staining intensity of rat thyroid tissues in the normal non-pregnant gruop (weak,n =2; moderate,n =5; strong,n =3) was stronger than that of rats lactating for 5 days (weak,n =7; moderate,n =3; x2 =5.895,P ＜ 0.05).But the expression of TSHR protein in thyroid tissues in the normal non-pregnant group was not significantly different statistically compared with the expression of TSHR protein in other groups (lactating for 10,15and 20 days) and weaning for 5 days group (all P ＞ 0.05).The expression of TSHR mRNA in thyroid gland was significantly different statistically between groups (F =2.970,P ＜ 0.05); the expression of TSHR mRNA in lactating for 5 days group (0.74 ± 0.13) was lower than that of the non-pregnant group (1.02 ± 0.24,P ＜ 0.05); and the expression of TSHR mRNA in the normal non-pregnant group was not significantly different statistically compared with those of other groups (lactating for 10,15 and 20 days) and weaning for 5 days group (all P ＞ 0.05).Conclusion TSHR is widely expressed in thyroid gland of lactating rats,but relatively lower in early lactation period.