Sun Xudong, Yuan Xue, Chen Liang, Wang Tingting, Wang Zhe, Sun Guoquan, Li Xiaobing, Li Xinwei, Liu Guowen
Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun, China.
College of Animal Science and Technology, Inner Mongolia National University, Tongliao, China.
Cell Physiol Biochem. 2017;42(3):1109-1119. doi: 10.1159/000478765. Epub 2017 Jun 30.
BACKGROUND/AIMS: Subacute ruminal acidosis (SARA) is a common disease in high-producing lactating cows. Rumenitis is the initial insult of SARA and is associated with the high concentrations of histamine produced in the rumen of dairy cows during SARA. However, the exact mechanism remains unclear. The objective of the current study is to investigate whether histamine induces inflammation of rumen epithelial cells and the underlying mechanism of this process.
Bovine rumen epithelial cells were cultured and treated with different concentrations of histamine and pyrrolidine dithiocarbamate (PDTC, an NF-κB inhibitor) cultured in different pH medium (pH 7.2 or 5.5). qRT-PCR, Western-blotting, ELISA and immunocytofluorescence were used to evaluate whether histamine activated the NF-κB pathway and inflammatory cytokines.
The results showed that histamine significantly increased the activity of IKK β and the phosphorylation levels of IκB α, as well as upregulated the mRNA and protein expression levels of NF-κB p65 in the rumen epithelial cells cultured in neutral (pH=7.2) and acidic (pH=5.5) medium. Furthermore, histamine treatment also significantly increased the transcriptional activity of NF-κB p65. High expression and transcriptional activity of NF-κB p65 significantly increased the mRNA expressions and concentrations of inflammatory cytokines, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and interleukin 1 beta (IL-1β), thereby inducing the inflammatory response in bovine rumen epithelial cells. However, inhibition of NF-κB p65 by PDTC significantly decreased the expressions and concentrations of the inflammatory cytokines induced by histamine in the rumen epithelial cells cultured in the neutral and acidic medium.
The present data indicate that histamine induces the inflammatory response of bovine rumen epithelial cells through the NF-κB pathway.
背景/目的：亚急性瘤胃酸中毒（SARA）是高产泌乳奶牛的常见疾病。瘤胃炎是SARA的初始损伤，与SARA期间奶牛瘤胃中产生的高浓度组胺有关。然而，确切机制仍不清楚。本研究的目的是调查组胺是否诱导瘤胃上皮细胞炎症以及该过程的潜在机制。
培养牛瘤胃上皮细胞，并用不同浓度的组胺和吡咯烷二硫代氨基甲酸盐（PDTC，一种NF-κB抑制剂）在不同pH值培养基（pH 7.2或5.5）中培养。采用qRT-PCR、蛋白质免疫印迹法、酶联免疫吸附测定和免疫细胞荧光法评估组胺是否激活NF-κB通路和炎性细胞因子。
结果显示，在中性（pH = 7.2）和酸性（pH = 5.5）培养基中培养的瘤胃上皮细胞中，组胺显著增加了IKKβ的活性和IκBα的磷酸化水平，同时上调了NF-κB p65的mRNA和蛋白表达水平。此外，组胺处理还显著增加了NF-κB p65的转录活性。NF-κB p65的高表达和转录活性显著增加了炎性细胞因子、肿瘤坏死因子α（TNF-α）、白细胞介素6（IL-6）和白细胞介素1β（IL-1β）的mRNA表达和浓度，从而诱导牛瘤胃上皮细胞的炎症反应。然而，PDTC对NF-κB p65的抑制显著降低了中性和酸性培养基中培养的瘤胃上皮细胞中组胺诱导的炎性细胞因子的表达和浓度。
目前的数据表明，组胺通过NF-κB途径诱导牛瘤胃上皮细胞的炎症反应。
