脂多糖刺激24 h后对仔猪腓肠肌炎症和蛋白质降解相关基因与miRNA表达的影响

Effects of Lipopolysaccharide on Inflammation and Protein Degradation-Related Genes and miRNA Expression in Gastrocnemius of Piglets after 24 h Stimulation

本试验旨在探讨脂多糖(LPS)刺激24 h后,与仔猪腓肠肌炎症和蛋白质降解相关基因与miRNA的表达变化。试验选用12头健康的28日龄断奶的杜×长×大三元杂交仔猪[体重为(7.09±0.90)kg],随机分为对照组(n=6)和LPS组(n=6),所有试验猪自由采食和饮水,预试期为15 d。在试验第15天,LPS组仔猪腹腔注射100μg/kg BW的LPS,并于注射24 h后麻醉屠宰,对照组仔猪则腹腔注射等量的无菌生理盐水,并于注射后立即麻醉屠宰,取腓肠肌样品待测。结果显示:LPS处理24 h后,腓肠肌炎症细胞因子白细胞介素-1β(IL-1β)和肿瘤坏死因子-α(TNF-α),以及Toll样受体4(TLR4)信号通路关键基因TLR4、骨髓分化因子88(MyD88)、白细胞介素受体相关激酶1(IRAK1)mRNA的表达量显著上升(P<0.05),且核因子-κB(NF-κB)和蛋白质降解相关基因叉头转录因子4(FOXO4)mRNA的表达量也显著上升(P<0.05)。LPS处理24 h后,腓肠肌miR-145的表达量显著上升(P<0.05),而miR-30b、miR-155、miR-132、miR-130a和miR-146a的表达量显著下降(P<0.05)。综上所述,LPS处理24 h后的仔猪腓肠肌损伤可能是通过TLR4信号通路介导FOXO4表达上调所引起的。miRNA可能参与LPS刺激后24 h腓肠肌炎症和蛋白质降解反应的调控。

This experiment was conducted to investigate the expression changes of genes and miRNA related to inflammation and protein degradation in gastrocnemius of weaned piglets challenged by lipopolysaccharide(LPS)at 24 h.Twelve healthy Duroc×Landrace×Yorkshine 28-day-old weaned piglets[body weight:(7.09±0.90)kg]were selected,and randomly divided into 2 groups:control group(n=6)and LPS group(n=6).All piglets were allowed ad libitum access to water and feed.On day 15 of experiment,the piglets in LPS group were injected with LPS(100μg/kg BW)and sacrificed at 24 h post-injection.The control group received the same amount of sterile saline,and sacrificed immediately after the injection.Gastrocnemius samples were selected for testing.The results showed as follows:at 24 h after LPS treatment,the mRNA expression levels of inflammatory factors interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α),as well as the key genes of Toll-like receptor 4(TLR4)signaling pathway including TLR4,myeloid differentiation factor 88(MyD88)and interleukin receptor-associated kinase 1(IRAK1)were significantly increased in gastrocnemius(P<0.05),and the mRNA expression levels of nuclear factor-κB(NF-κB)and protein degradation-related gene forkhead box O4(FOXO4)were also significantly increased(P<0.05).Moreover,miR-145 expression level in gastrocnemius was significantly increased(P<0.05),and the expression levels of miR-30b,miR-155,miR-132,miR-130a and miR-146a were significantly decreased at 24 h after LPS treatment(P<0.05).The results indicate that the gastrocnemius injury can be caused by the up-regulation of FOXO4 expression mediated by TLR4 signaling pathway at 24 h after LPS treatment.The miRNA may be involved in muscle inflammation and protein degradation at 24 h after LPS stimulation.