饲喂高精料日粮的奶牛瘤胃液对瘤胃上皮细胞炎症因子表达量的影响

Effects of rumen fluid from dairy cows fed high concentrate diet on expression of inflammatory factors in bovine rumen epithelial cells

本研究旨在探索饲喂高精料日粮的奶牛瘤胃液对奶牛瘤胃上皮细胞(BRECs)炎症因子基因表达量的影响。利用qRT-PCR等方法,研究饲喂高精料日粮的奶牛瘤胃液对BRECs炎症因子、趋化因子以及抗氧化指标的影响。试验分为2个组:对照组(精粗料比为50∶50)和高精料组(精粗料比为65∶35),各自培养BRECs 6 h,每组设6个重复。结果表明,与对照组相比,高精料组BRECs炎症因子基因IL-1β、IL-6、TNF-α的mRNA表达量显著提高。饲喂高精料日粮的奶牛瘤胃液能显著提高BRECs中CCL2、CCL20、CXCL2、CXCL8、CXCL9基因的mRNA表达量。饲喂高精料日粮的奶牛瘤胃液显著降低TLR2、TLR4基因的mRNA表达量,但并未显著改变CD14、MD2、MyD88基因以及下游信号通路白细胞介素-1受体相关激酶基因IRAK1、TRAF6的mRNA表达量。值得注意的是,饲喂高精料日粮的奶牛瘤胃液显著上调BRECs中PEPT1基因的mRNA表达量(P<0.05),推测PEPT1可能转运饲喂高精料日粮的奶牛瘤胃液中的细菌小肽进入细胞,引起炎症反应。饲喂高精料日粮的奶牛瘤胃液显著提高BRECs中丙二醛(MDA)含量和过氧化氢(HO)含量,然而,超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、总抗氧化物质(T-AOC)含量显著降低。说明,饲喂高精料日粮的奶牛瘤胃液能够促进瘤胃上皮细胞的炎症反应并加强免疫应答。此外,饲喂高精料日粮的奶牛瘤胃液对奶牛瘤胃上皮具有损伤作用。

The purpose of this study is to explore the effects of rumen fluid from dairy cows fed high concentrate diet(HCRL) on expression of inflammatory factors in bovine rumen epithelial cells(BRECs). The effect of HCRL on the inflammatory factors, chemokines and antioxidant indices in BRECs was investigated using qRT-PCR. The experiment was divided into two groups: BRECs were cultured for six hours in control group(ratio of concentrate to coarse material was 50∶50) and high concentrate group(ratio of concentrate to coarse material was 65∶35) with six replicates in each group. These results showed that compared with control group, the mRNA expression levels of IL-1β, IL-6 and TNF-α in high concentrate group were significantly increased. In addition, HCRL could significantly enhance the mRNA expression levels of CCL2, CCL20, CXCL2, CXCL8 and CXCL9 in BRECs, and significantly reduce the mRNA expression levels of TLR2 and TLR4, but did not significantly change the mRNA expression levels of CD14, MD2, MyD88, IRAK1 and TRAF6. Notably, the HCRL could significantly enhance the mRNA expression level of PEPT1 in BRECs. It was suggested that PEPT1 may transport the small bacterial peptides into the cells, resulting in inflammatory response. Rumen fluid from dairy cows fed high concentrate diet significantly increased malondialdehyde(MDA) content and hydrogen peroxide(HO) content in BRECs. However, the activities of superoxide dismutase(SOD) and glutathione peroxidase(GSH-PX) and total antioxidant capacity(T-AOC) were significantly reduced. The results indicate that the HCRL can promote the inflammation response of rumen epithelial cells and strengthen the immune response. In addition, the HCRL has a damaging effect on the rumen epithelium of dairy cows.