The Structure Of Mammary Gland And Expression Of Hormone Receptors In Hu Sheep With Four Nipples

The objective of this study was to review whether Hu sheep with four nipples had a potential higher performance of lactation and lactation mechanism. In this study, the breast tissue samples were taken from two groups of Hu sheep(four nipples and two nipples) during incubation, pregnancy, lactation and nonpregnant period. The changes of mammary gland tissue morphological between two groups during different development stages were observed by HE staining, the real-time quantitative PCR(RT-qPCR) was used to detect the relative m RNA expression levels of ERα, PR, PRLR, GHR, IGF-IR gene. The distribution of receptor protein was detected by immunohistochemistry(IHC). Western Blotting was used to measure the protein level in mammary gland during different stages. The main findings are showed as follows:1. In connective tissue, the numbers of catheter were dense in test group than that of control group during incubation period, and the numbers of gland bubble in test groups were more than that of control groups during pregnancy and lactation period. The volume of gland bubble was the largest during lactation, and gland bubbles were gradully collapsed and morphological structure of breast was changed after weaning. It was showed that the mammary gland structure of Hu sheep with four nipples was more developed than that of test group.2. The mRNA expression levels of ERα, PR, PRLR, IGF-IR were gradually increased from incubation to lactation, the expression levels in nonpregnant period were lower than those of lactation. The mRNA expression levels of GHR was gradually increased from incubation to pregnancy, and then it was declined from lactation to nonpregnant period.3. In breast tissues of Hu sheep, the protein trend of ERα, PR, PRLR, GHR, IGF-IR were consistent with m RNA expression levels.4. The mRNA expression and protein levels of ERα, PR, PRLR, GHR, and IGF-IR in test groups were higher than those of control groups during incubation, pregnancy, lactation and nonpregnant period.In summary, not only the breast tissue of Hu sheep with four nipples was more develope d, but also receptor genes associated with breast development hormone and their protein expression levels were higher than those of control groups.This showed that Hu sheep with four nipples had higher potential lactation performance.