肽转运载体PepT1介导鸡蛋生物活性肽调控仔猪肠道炎症反应的研究

Intestine is susceptible to pathogen infection that trigger inflammatory response. Small peptide transporter PepT1 may be a potent therapeutic target against inflammatory responses in the intestine. And many bioactive peptides have been confirmed to have anti-inflammatory activity. However, the role of PepT1 in anti-inflammatory responses has not been reported in the porcine intestine. The project is conduct to study the changes of PepT1 expression and inflammatory responses pathways in intestinal inflammation induced by DSS; investigate the effect of RNAi or overexpression of PepT1 on cell proliferation and inflammatory responses in LPS-challenged intestinal epithelial cells IPEC-J2; study the regulation of eggs bioactive peptides IRW and IQW on PepT1 transport activity and inflammatory responses in the inestine of piglets. The results is to clarify the role of PepT1 in inflammatory responses and the regulatory mechanisms of eggs bioactive peptides on the intestinal inflammation mediated by PepT1. The aim is to develop regulatory targets and nutritional regulated manners to alleviate intestinal inflammation in piglets and provide a theoretical basis for the applications of egg active peptide in porcine production.

仔猪肠道易受病原等侵袭诱导炎性反应，小肽转运载体PepT1可介导肠道炎症而成为抗炎治疗潜在的新靶点；很多生物活性肽被证实具有抗炎活性，但在仔猪肠道是否通过PepT1介导发挥抗炎作用尚未见报道。本项目拟利用DSS诱导的仔猪肠道炎症模型，研究仔猪肠道炎症条件下PepT1和相关炎症通路变化；干扰或过表达肠上皮细胞IPEC-J2 PepT1，LPS诱导炎症反应，分析细胞增殖和炎症反应通路变化；通过日粮添加鸡蛋活性肽IRW和IQW，研究其对仔猪肠道PepT1转运活性和炎症反应的调控作用。以期揭示PepT1在仔猪肠道炎症反应中的作用，阐明鸡蛋活性肽通过PepT1调控肠道炎症反应的作用机制，为缓解仔猪肠道炎症反应提供调控靶点和营养干预手段，为鸡蛋活性肽在猪生产中的开发利用提供理论依据。

仔猪肠道易受病原等侵袭诱导炎性反应，鸡蛋活性肽IRW和IQW表现出缓解炎症的作用。首先，我们研究了鸡蛋活性肽IRW和IQW对断奶仔猪生长性能及肠道菌群的影响，设置了对照组、IRW组（添加0.1g/kg IRW）和IQW组（添加0.1g/kg IQW）。结果表明：与对照组相比，日粮中添加IRW显著提高了仔猪的增重，IRW显著升高了微生物多样性指数；日粮中添加鸡蛋活性肽IRW和IQW使得肠道微生物积极参与碳水化合物、膜转运、能量代谢及信号转导等。随后我们分析了鸡蛋活性肽对炎症状态下肠道微生物以及PepT1的表达的影响，设置了对照组（基础日粮组，腹腔注射生理盐水，CTRL组）、LPS组（腹腔注射LPS）、IRWPS组（日粮添加0.1g/kg IRW，腹腔注射LPS）和IQWPS组（日粮添加0.1g/kg IQW，腹腔注射LPS）。结果表明：腹腔注射LPS增加了肠道损伤和炎症细胞浸润；而日粮中添加IRW和IQW可缓解由LPS诱导的肠道损伤，同时与CTRLPS组相比，鸡蛋活性肽降低了TNF-α、IL-1β、IL-6及MPO水平； LPS导致了PepT1表达降低，鸡蛋活性肽可恢复PepT1的表达。此外，在由LPS诱导的肠道炎症状态下，鸡蛋活性肽IRW和IQW降低相关炎症因子水平及结肠中PepT1的表达。总之，鸡蛋活性肽IRW对断奶仔猪生长性能具有积极作用，在肠道损伤的状态下，IRW和IQW表现出有效的缓解肠道损伤和恢复肠道微生物及维持肠道微生物功能的作用。