哺乳期大鼠乳腺组织促甲状腺激素受体的表达

Expression of thyroid-stimulating hormone receptor in mammary gland tissue of lactating rats

目的观察哺乳期大鼠乳腺组织促甲状腺激素受体（TSHR）蛋白和mRNA表达，探索乳腺的摄碘机制。方法选择成年Wistar大鼠80只，其中雌性60只，雄性20只，体质量为210～250g。将雌性大鼠按体质量随机分为6组：正常未孕组，哺乳第5、lO、15、20天组和断乳第5天组，每组10只。常规饲料喂养，自由饮用自来水。将除正常未孕组外的其他5组雌鼠与雄性大鼠按3：1合笼交配，分别在哺乳第5、10、15、20天和断乳第5天时股动脉取血处死动物，取乳腺组织，采用免疫组织化学法和实时荧光定量PCR法检测TSHR蛋白和mRNA表达。结果TSHR蛋白表达于大鼠的乳腺腺泡与导管的上皮细胞质中。各组间TSHR蛋白表达水平比较差异有统计学意义（X2=14．612，P〈0．05），正常未孕组大鼠乳腺组织的染色强度（弱阳性4例、中阳性6例）弱于哺乳第5天组（弱阳性2例、中阳性3例、强阳性5列）和哺乳第10天组（难以判断1例、中阳性4例、强阳性5列，X2值分别为4．113、5．250，P均〈0．05）。各组间乳腺TSHRmRNA表达水平比较差异有统计学意义（F=20．488，P〈0．05）。其中哺乳第10天组（O．31±0：06）较哺乳第5天组（0．22±0．04）TSHRmRNA表达明显升高（P〈0．01），哺乳第15天组（0．164-O．08）较哺乳第5天组TSHRmRNA表达明显降低（P〈0．05）。结论TSHR广泛表达于哺乳期大鼠乳腺组织中。在哺乳早期乳腺摄碘功能较强，此时机体可能更易发生碘营养缺乏．应合理补充碘剂。

Objective To observe the protein and mRNA expression of thyroid-stimulating hormone receptor （TSHR） in mammary gland tissue of lactating rats, and to explore iodine uptake mechanism. Methods Eighty adult Wistar rats （60 female and 20 male）, weighting 210 - 250 g were selected. All female Wistar rats were randomly divided into 6 groups according to their body mass： normal non-pregnant group, lactating for 5-, 10-, 15- and 20- day groups and weaning for 5 days group, 10 rats in each group. All rats were fed with conventional fodder and tap water freely. In addition to the normal non-pregnant group, other five groups of female and male rats were mated at 3 ： 1, respectively. Then the rats in all groups were killed on the 5th, 10th, 15th and 20th day after lactation and on the 5th day after weaning to get the mammary gland tissue. The protein and mRNA expression of TSHR were determined by immunohistochemical staining and real-time quantitative PCR. Results TSHR protein was expressed in mammary acinar and ductal epithelial cytoplasm. The expression of TSHR in mammary gland showed significant differences between groups （X2 = 14.612, P 〈 0.05）, the staining intensity of mammary gland tissue in normal non-pregnant rats（weak, n = 4; moderate, n = 6） was weaker than that of lactating for 5 days（weak, n = 2; moderate, n = 3; strong, n = 5） and 10 days groups（barely detectable, n = 1; moderate, n = 4; strong, n = 5; X2 = 4.113, 5.250, all P 〈 0.05）. The expression of TSHR mRNA in mammary gland showed significant differences between groups（F = 20.488, P 〈 0.05） ; the expression of TSHR mRNA inlactating for 10 days group（0.31 ± 0.06） was higher than that of lactating for 5 days group（0.22 ± 0.04, P 〈 0.01）, and the expression of lactating for 15 days group （0.16 ± 0.08 ） was significantly lower than that of lactating for 5 days group （P 〈 0.05 ）. Conclusions TSHR is widely expressed in mammary gland of lactating rats. The iodine uptake of mammary gland is enhanced in early lactation period when the body may be more susceptible to iodine deficiency, therefore iodine should be supplemented reasonably.