乳腺发育不良和泌乳障碍严重影响母畜生产能力和新生幼畜生长，而激素水平紊乱是其产生的重要原因之一。研究显示，A型钠离子依赖性中性氨基酸转运体2（SNAT2）在组织发育中有重要作用，17β-雌二醇（E2）调控SNAT2在乳腺组织的表达。然而SNAT2在E2和孕酮（P4）紊乱引发的泌乳障碍中的作用尚不清楚。本项目以山羊为研究对象，应用qRT-PCR、Western blot、免疫荧光、流式细胞术、电镜和ELISA等方法，首先明确生理及紊乱E2/P4条件下山羊妊娠期乳腺发育及山羊乳腺上皮细胞（GMECs）增殖和分泌乳蛋白过程中SNAT2表达规律；通过基因敲除、RNAi和基因过表达等技术探讨SNAT2表达变化对GMECs增殖、紧密连接及分泌乳蛋白的影响；进一步探讨mTOR信号通路在SNAT2调节GMECs增殖与功能中的作用。本项目为深度解析激素紊乱引发的乳腺发育不良及泌乳障碍提供新思路和理论依据。

Mammary gland dyslpasia and postpartum lactation disorder can seriously impact the production capacity of dams and the growth of newborns, while hormonal disorders is one of the important factors leading to the above problems. Studies have shown that type-A sodium-dependent neutral amino acid transporter 2 (SNAT2) played an important role in regulating tissue development, and that 17β-estrotial (E2) regulated the expression of SNAT2 in the mammary gland. However, the role of SNAT2 in E2 and progesterone（P4）disoder–mediated dysgalactia is unclear. Here, the goats were exploited in the current study, qRT-PCR, Western blot, Immunofluorescence, Flow cytometry, Electronic speculum and ELISA technologies were applied to firstly clarify the expression pattern of SNAT2 during pregnancy of mammary gland development or the proliferation and lactation of goat mammary epithelial cells (GMECs) with different ratios of E2/P4. Then the knocking-out, RNAi, and over-expression of SNAT2 were carried out to explore the effect of SNAT2 protein level-changes on the proliferation, apoptosis, tight junction, and secretion of GMECs. Further, we would explore whether mTOR signaling pathway played a role in SNAT2 regulating proliferation and secretion of GMECs. The current study would provide new insights and experimental basis for profoundingly analysing mammary gland dysplasia and lactation disorder induced by hormonal disorders.