脂多糖刺激后不同时间点断奶仔猪回肠和结肠中转化生长因子β1及Smads信号通路的动态变化

Developmental Changes of TGF-β1 and Smads Signaling Pathway in Ileum and Colon of Piglets at Different Timepoints after LPS Challenge

本试验旨在研究脂多糖(LPS)刺激后不同时间点断奶仔猪回肠和结肠中肠道损伤修复关键因子转化生长因子β1(TGF-β1)以及Smads信号通路关键分子的变化。选取42头(7.09±0.9)kg的21日龄杜×长×大断奶仔猪,按照注射LPS后时间点的不同随机分成7个处理,每个处理6头猪。预试14 d后,仔猪腹膜注射100μg/kg BW的LPS,分别在注射前(0 h)和注射后1、2、4、8、12、24 h屠宰仔猪,取回肠和结肠样品,检测TGF-β1以及Smads信号通路相关因子的基因表达。结果表明:LPS刺激后,回肠中的TGF-β1在2、4 h显著升高,TGF-βR1和TGF-βR2在24 h同时达到峰值(P<0.01);Smad2在1、4、12 h都显著上升,并在24 h与Smad3、Smad4同时达到峰值(P<0.01);Smad7在2、8 h显著上升,24 h到达峰值(P<0.01);结肠中的TGF-β1及TGF-βR1在24 h显著上升,TGF-βR2在12 h显著上升;Smad2、Smad4以及Smad7在24 h显著上升,而Smad3在8 h显著升高。由此可见,LPS刺激肠道后,修复因子TGF-β1及其Smads信号通路在24 h被全面激活,从而参与到肠道损伤修复过程。

The aim of this study was to investigate the changes of transforming growth factor β1(TGF-β1)and related Smads signaling pathways in the ileum and colon at different time points after lipopolysaccharide(LPS)stimulation.A total of 42 weaned piglets(7.09±0.9)kg aged 21 days were randomly divided into 7 treatments according to the time points(before the injection of LPS(0 h)and 1,2,4,8,12 and 24 h after LPS injection),and 6 pigs in each treated group.At day 14,100μg/kg body weight(BW)of LPS was intraperitoneally injected into the treated piglets.The piglets were slaughtered and the ileum and colon samples were harvested to detect the gene expression levels of TGF-β1 and Smads signaling pathway.The results showed that after the LPS stimulation,TGF-β1 in the ileum increased significantly at 2,4 h,and its receptors(TGF-βR1 and TGF-βR2)peaked at 24 h(P<0.01).The Smad2 increased significantly at 1,4 and 12 h post LPS stimulation,and reached the peak at 24 h(P<0.01)with Smad3 and Smad4;The mRNA expression of Smad7 increased significantly at 2,8 h and peaked at 24 h(P<0.01).After stimulation with LPS,the mRNA expression of TGF-β1 and its receptor TGF-βR1 in the colon increased significantly at 24 h,and TGF-βR2 increased significantly at 12 h.The mRNA expression levels of Smad2,Smad4 and Smad7 increased significantly at 24 h,while Smad3 increased significantly at 8 h.After LPS stimulation,the repair process of intestine will be activated rapidly both in small and large intestine,and TGF-β1 and Smads signaling pathway will be fully activated at 24 h,which was speclating to participate in the regulation of intestinal repair process.