CS纳米粒对LPS引起的奶牛胃肠上皮紧密连接损伤的保护及其机制研究

SARA is a common metabolic disease in dairy intensive culture. In this state, LPS damages TJs and causes systemic inflammatory syndrome. It has been proved that CS can alleviate LPS-induced inflammatory response through MAPK and NF-κB Signaling pathway and TJs are also regulated by MAPK and NF-κB. Previous results show that CS nanoparticles can repair TJs damaged by LPS. How CS nanoparticles how to repair TJs and whether CS nanoparticles can regulate TJs through anti-inflammatory pathway remains need further studied. In this project, CS nanoparticles were synthesized from CS oligosaccharide. CS nanoparticles were used to treat LPS-treated epithelial cells and tissues in vitro to study the repair effect of CS nanoparticles on LPS-damaged TJs. Then, inhibitors were used to block TLR4, MPKA and NF-κB pathways, respectively, to study the regulation of TJs damage by CS nanoparticles through TLR4-mediated MAPK and NF-κB pathways. In conclusion, the protective mechanism of CS nanoparticles through regulating TLR4-mediated MAPK and NF-kappa B pathway on LPS-induced TJs was systematically elaborated. This project is to further deepen the destruction mechanism of TJs caused by LPS, and it provides a theoretical basis for the research of CS protection mechanism for TJs and the rational application of CS.

SARA是奶牛集约化养殖常见代谢病，此时LPS损坏TJs而引发全身炎症综合征。已证实CS可通过MAPK、NF-κB缓解LPS引发的炎性反应，且TJs也受MAPK、NF-κB的调控。前期结果表明，CS纳米粒可修复LPS损伤的TJs，那么，CS纳米粒如何修复TJs且能否通过抗炎通路调控，有待于进一步研究。因此，本项目先以低聚CS为材料合成CS纳米粒，以CS纳米粒处理经LPS处理的上皮细胞和离体组织，研究CS纳米粒对LPS损伤的TJs的修复作用；然后，利用抑制剂分别阻断TLR4、MPKA、NF-κB通路，研究CS纳米粒通过TLR4介导的MAPK、NF-κB通路对TJs损伤的调控。综上结果，系统阐述CS纳米粒调控TLR4介导的MAPK、NF-κB通路对LPS引起损伤的TJs保护机制。本项目是对LPS引起的TJs破坏机制的进一步深入，同时为为CS对TJs保护机制研究和CS合理应用提供理论依据。

SARA是奶牛集约化养殖常见代谢病，此时LPS损坏紧密连接（Tight Junctions, TJs）而引发全身炎症综合征。CS纳米粒可通缓解LPS引发的炎性反应，但CS纳米粒如何修复TJs且能否通过抗炎通路调控，有待于进一步研究。因此本研究聚焦CS纳米粒对TJs的影响以及此过程是否通过MAPK、NF-κB炎性通路来进行调控的。研究发现：LPS可以使TJs损伤，而这个过程是通过MAPK、NF-κB炎性通路来完成的。CS纳米粒可以有效缓解LPS引起的TJs损伤，主要是通过影响TJs蛋白Claudin-4的磷酸化及蛋白分布来完成的，而且，此过程是CS纳米粒听过上调IL-10和下调TNF-α来激活MAPK、NF-κB炎性通路最终实现的，使损伤的胃肠道屏障得到有效恢复。本研究表明CS纳米粒通过MAPK、NF-κB炎性通路来影响TJs的合成和分布，从而缓解胃肠道的炎症反应。本项目是对LPS引起的TJs破坏机制的进一步深入，同时为为CS对TJs保护机制研究和CS合理应用提供理论依据。