母乳源Exosome-miR-145-5p通过TLR4调控肠道屏障对新生儿坏死性小肠结肠炎的防治作用及机制研究

母乳喂养可降低坏死性小肠结肠炎（NEC）的发病率，但确切机制尚不清楚。我们前期发现足月儿母亲的母乳源外泌体（Exosome）对防治NEC具有显著作用；芯片结果显示母乳源Exosome中 miR-145-5p表达上调，预实验证实Exosome-miR-145-5p能缓解LPS导致的肠上皮细胞损伤和紧密连接。生物信息学预测及实验证明TLR4是miR-145-5p潜在靶基因，TLR4亦是NEC疾病进展的关键因子。我们推测miR-145-5p通过靶基因TLR4调控肠道屏障可能是防治NEC的新机制。本研究拟分析：不同孕周母乳中Exosome-miR-145-5p的含量变化，进而通过细胞模型、NEC动物模型、分子生物学等手段，从in vivo 和in vitro 两方面研究miR-145-5p与TLR4作用后调控肠道屏障发挥对NEC保护作用的机制，为今后NEC的防治提供新的理论依据和潜在的干预靶标。

Breastfeeding can reduce the incidence of necrotizing enterocolitis (NEC), but the exact mechanism remains unclear. Our previous study indicates that breast milk-derived Exosome of full-term mothers had a significant effect on the prevention and treatment of NEC. Our high-throughput screening data revealed that the expression of miRNA-145-5p in breast milk-derived Exosome was up-regulated. Furthermore, Exosome-derived miRNA-145-5p could alleviate LPS-induced intestinal epithelial cells damage and tight junction. Bioinformatics analysis predicted miRNA-145-5p contains a binding site for TLR4, and TLR4 is an important marker of NEC. We hypothesized that miR-145-5p regulated intestinal barrier by targeting TLR4 to protect NEC. The purpose of this study is to analyze the changes of Exosome- derived miRNA-145-5p in breast milk of different gestational weeks, and to study the mechanism of intestinal barrier protection by Exosome-derived miRNA-145-5p regulating TLR4 in vivo and in vitro by cell model, NEC animal model and molecular biology, in order to provide new theoretical basis and potential intervention targets for the prevention and treatment of NEC in the future.