茯苓多糖通过NF-κB信号通路修复早期断奶仔猪肠道氧化损伤的机制

Early-weaned piglets often easily experience oxidative stress which will cause intestinal injury and futher lead to gastrointestinal diseases. Gastrointestinal tract is the most likely position for against oxidative stress. As a traditional Chinese medicinal fungus, the main component of Poria cocos is Pachymaran, which of its derivate Carboxymethylpachymaran (CMP) is proved to have many strong bioactivities, including immunoregulation, anti-tumor,anti-oxidant , anti-inflammatory and etc. However, the regulation roles and its mechanism of CMP against intestinal oxidative damage remain unclear. Therefore, the present project will be conducted using a piglet model with oxidative stress induced by Diquat and the IPEC-J2 cell model with damage induced by H2O2 to study the regulation effects of CMP on intestinal structure and function in early-weaned piglets, and the proliferation, differentiation and antioxidant capacity of enterocytes; and to study the regulation effects of CMP on intestinal Nf-kappa B signal pathway (comfirmed to be one of the major pathways to regulate oxidative stress) and its upstream molecular PI3K/Akt. The aim of this study is to clarify the protective mechanisms of CMP on intestinal oxidative damage in piglets, and provide interventions of resisting oxidative damage of gastrointestinal tract and alleviating early-weaned stress in piglets, as well as providing the theoretical foundations for development and utilization of the CMP.

早期断奶极易诱导仔猪机体发生氧化应激，引发肠道损伤和胃肠疾病。胃肠道是抗氧化剂最有望发挥抗氧化作用的场所。茯苓作为中国传统药用真菌，其主要成分茯苓多糖经化学修饰后所得衍生物羧甲基茯苓多糖（CMP）具有很强的免疫调节、抗肿瘤、抗氧化、抗炎等生物活性，但目前对CMP调控肠道氧化损伤修复作用及其机制尚不清楚。本项目拟利用Diquat诱导的仔猪氧化应激模型与H2O2诱导的IPEC-J2细胞损伤模型，研究CMP对早期断奶仔猪肠道结构功能和肠上皮细胞增殖分化及抗氧化能力的调控作用，通过研究CMP对肠道NF-κB信号通路（参与氧化应激调控的主要途径之一）及其上游分子PI3K/Akt的调控作用，阐明CMP缓解早期断奶仔猪肠道氧化应激损伤的机理，为防治胃肠道氧化损伤、减缓仔猪早期断奶应激提供干预手段，并为CMP的开发利用提供理论依据。

本试验探究日粮中添加CMP 对NF-κB信号通路和仔猪肠道氧化应激调控作用，并深入研究CMP在调控仔猪氧化应激反应中的作用机理。本项目利用Diquat诱导的仔猪氧化应激模型与H2O2诱导的IPEC-J2细胞损伤模型，研究了CMP对早期断奶仔猪肠道结构功能和和抗氧化能力的调控作用。本试验探究日粮中添加CMP 对NF-κB信号通路和仔猪肠道氧化应激调控作用，并深入研究CMP在调控仔猪氧化应激反应中的作用机理。本项目利用Diquat诱导的仔猪氧化应激模型与H2O2诱导的IPEC-J2细胞损伤模型，研究了CMP对早期断奶仔猪肠道结构功能和和抗氧化能力的调控作用。. 仔猪试验结果表明：日粮添加CMP能够缓解Diquat诱导氧化应激造成的组织病理学损伤，维护肠道组织结构完整；可显著提高总抗氧化活性活性，而显著降低MDA含量；可显著降低Diquat处理仔猪血清中IL1β、IL6、IL8、IL12、GM-CSF和TNFα等促炎性细胞因子含量以及肠道组织中IL8、GM-CSF、IL1β等促炎性细胞因子mRNA丰度，而显著提高IL4和TGFβ等抗炎性细胞因子水平（P < 0.05）；降低Diquat处理仔猪的p-NF-κB、IKKα/β和IκB蛋白表达水平（P < 0.05）。综上结果，CMP添加能缓解Diquat诱导氧化应激反应，可能与抑制NF-κB信号通路有关。猪肠上皮细胞结果表明： Diquat处理显著促进细胞凋亡，并上调TNFα、IL6、GM-CSF 和 MCP1/CCL2 等促炎性因子mRNA水平（P<0.05）；可显著降低MDA的含量，提高SOD酶的活性（P < 0.05）； CMP可降低IKKα/β蛋白表达水平，抑制NF-κB核转移，降低IL1β、IL6、GM-CSF等促炎性因子mRNA水平，缓解Diquat诱导的猪肠上皮细胞IPEC-J2氧化损伤（P < 0.05）。 . 综上提示茯苓多糖具有较好动物机体抗氧化应激作用，可为动物胃肠道抵御氧化损伤、减缓仔猪断奶应激提供干预手段，对畜牧业可持续性发展具有重要的理论和实践意义.