基于JAK2/Stat5通路调控探讨疏肝健脾法促进产后缺乳大鼠乳腺泌乳的机制

Breast milk is considered as the most suitable natural food for infants and young children's physical and mental development in the worldwide.Breast feeding has obvious benefits for mother and infant's health. Under the influence of various factors，the incidence of postpartum hypogalactia deficiency increased year by year. To study the mechanism of lactation and to search for effective therapeutic targets，which have great clinical significance and social benefits. The model hypogalactia rats combining disease with syndrome will be the research objects，We will study the clinical effect of Shugan Jianpi traditional Chinese medicine on the rats lactation and detect prolactin levels in serum and mammary gland of rats by ELISA.The morphological structure and the distribution of prolactin and its receptor in the breast tissue will be observed by immunohistochemistry. mRNA and protein levels of prolactin receptor，Jak2/Stat5 pathway factor and target genes will be detected by RT-PCR and Western blot methods. Through these measures to elaborate the molecular mechanism of traditional Chinese medicine，mechanism and possible dose effect relationship. Our research will help to provide theoretical basis and therapeutic targets for the prevention and treatment of postpartum hypogalactia，help to provide the basis for the research and development of traditional lactagogue Chinese medicine.

母乳是全球公认最适合婴幼儿身心发展的天然食品，母乳喂养对母婴健康均有显著益处。受多种因素影响，产后缺乳发病率逐年升高，因此深入研究乳腺泌乳调控机制，寻找有效治疗方法和靶点对防治缺乳具有重大的临床意义与社会效益。课题组拟基于前期研究，通过建立产后缺乳病证结合大鼠模型，探讨疏肝健脾法治疗产后缺乳的临床疗效。ELISA法检测血清、乳腺组织催乳素水平、免疫组化法观察乳腺组织形态结构和催乳素及其受体分布、RT-PCR及Western blot检测乳腺组织催乳素受体、Jak2/Stat5通路因子及相关靶基因的mRNA及蛋白质水平，以此阐述疏肝健脾法通过JAK2/Stat5信号转导途径促进乳腺泌乳的分子机制以及治疗产后缺乳的作用机理和可能存在的剂量-效应关系。所得结果有助于探索中医药防治产后缺乳的起效机制，为中医药防治产后缺乳提供分子生物学领域的研究基础，有助于为催乳中药研发提供实验基础与依据。

产后缺乳，是指产妇哺乳期间乳汁减少或无乳汁，而无法满足婴儿需求。前期研究发现，临床上，肝郁脾虚证是最常见的证候之一。本研究模拟西医病因病理，甲磺酸溴隐亭激活多巴胺受体抑制催乳素分泌，建立西医大鼠产后缺乳模型；模拟中医病机，慢性束缚致大鼠肝郁，肝疏泄不及、肝郁横逆犯脾致肝郁脾虚，建立产后缺乳中医证候模型，并通过动物宏观表征、临床与实验室指标等方法综合评价可成功构建产后缺乳大鼠病证结合动物模型。与模型组相比，疏肝健脾法的中药低、中、高剂量组均可改善缺乳大鼠的宏观表征、增加大鼠体质量和仔鼠净增重，增加大鼠每小时泌乳量，增加大鼠水平运动和垂直运动次数，增加大鼠尿D-木糖排泄率，降低过高的血浆CRH、ACTH、COR水平，升高GAS及PRL水平（P＜0.05），且中药中剂量组效果最好。病理学方面，与模型组相比，西药对照组和中药低、中、高剂量组均可促进乳腺组织向泌乳活跃期发育，表现为腺泡腔充盈、腺泡上皮细胞数量增多、结缔组织和脂肪组织退化，同时增加乳腺组织中PRL和PRLR的表达。进一步深入研究疏肝健脾法作用的分子机制发现，疏肝健脾法促进产后缺乳大鼠乳腺泌乳的机制可能与促进PRL与其受体结合，激活JAK2/STAT5A信号转导通路，上调CylinD1、下调p21WAF/Cip1、下调p27kip1、上调抗凋亡基因Bcl-xl、Bcl-2，并上调β-casein基因表达密切相关。