前期研究表明热应激导致猪/大鼠空肠肠绒毛顶端缺血损伤，自噬水平升高，miR-23b显著下降， L-Arg可缓解动物肠道热损伤。MiR23b在热损伤中是否通过其靶基因对细胞自噬调控？L-Arg如何调控热损伤中自噬机制？针对上述问题，本项目采用miRNA海绵，特异性抑制小肠上皮细胞IPEC-1/IEC-6中miR23b表达，结合热应激深度测序数据，运用靶基因预测软件研究miR23b与自噬相关靶基因ATG12的关系，并通过荧光素酶报告基因验证。复制热应激模型及miR23b抑制热应激模型，光镜及电镜观察细胞形态及自噬体， LC3II，mTOR、Casp12等评价自噬变化，探讨miR23b对热损伤中靶基因与自噬的调节，对关键信号通路的调控；研究L-Arg对热损伤细胞miR23b的调控及对自噬的调控机制。通过靶动物回归实验，选择关键靶点在猪热应激试验中验证。本课题为缓解肠道热损伤机制提供新的理论支持。

Previous studies showed that the microcirculation ischemia of jejunum villus happened in both pig and rat in heat stress. The level of autophagy increased at the top of jejunum villus, miR-23b significantly decreased, and L-Arg relieve the thermal damage of small intestine. However, what is the target gene of autophagy in intestinal epithelial cell thermal damage and how miR23b regulates its predicted target gene and autophagy? How L-Arg relieves the injury of jejunum and regulates miR23b and autophagy? In response to these problems, this study used miRNA sponge, specific inhibit the expression of miR23b in epithelial cells of small intestine (IPEC-1/IEC-6). Integrated with deep sequencing data of heat stress, predicted the target gene—an autophagy related target gene ATG12-- of miR23b by target gene prediction software (miRDB/PICTAR) .Then verifies through the Luciferase Report Gene assay. This study copies the heat stress model and miR23b Inhibition heat stress model, observes the ultrastructure of autophagosome by microscope and TEM, detects LC3II, mTOR, Casp12 and others to evaluate the autophagy changes, explores the regulation of miR23b and related signaling pathways in the thermal damage, and studies the regulation of L-Arg on miR23b and autophagy in IPEC-1/IEC-6 in thermal damage. Finally, verifies the key target of autophagy in pigs in heat stress induced injury. The study aims to provide the theoretical basis of the mechanism of intestinal thermal damage.