State Key Laboratory of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
College of Animal Science and Technology, Nanjing Agricultural University, Nanjing 210095, China.
J Anim Sci. 2022 Feb 1;100(2). doi: 10.1093/jas/skac005.
Disruption of the ruminal epithelium barrier occurs during subacute ruminal acidosis due to low pH, hyper-osmolality, and increased concentrations of lipopolysaccharide and histamine in ruminal fluid. However, the individual roles of lipopolysaccharide and histamine in the process of ruminal epithelium barriers disruption are not clear. The objective of the present investigation was to evaluate the direct effect of lipopolysaccharide and histamine on the barrier function of the ruminal epithelium. Compared with control (CON), histamine (HIS, 20 μM) increased the short-circuit current (Isc; 88.2%, P < 0.01), transepithelial conductance (Gt; 29.7%, P = 0.056), and the permeability of fluorescein 5(6)-isothiocyanate (FITC) (1.04-fold, P < 0.01) of ruminal epithelium. The apparent permeability of LPS was 1.81-fold higher than HIS (P < 0.01). The mRNA abundance of OCLN in ruminal epithelium was decreased by HIS (1.1-fold, P = 0.047). The results of the present study suggested that mucosal histamine plays a direct role in the disruption of ruminal epithelium barrier function, whereas lipopolysaccharide (at a pH of 7.4) has no effect on the permeability of rumen tissues ex vivo.
在亚急性瘤胃酸中毒期间，由于瘤胃液体中 pH 值降低、高渗透压以及内毒素和组胺浓度增加，破坏了瘤胃上皮屏障。然而，内毒素和组胺在瘤胃上皮屏障破坏过程中的作用尚不清楚。本研究旨在评估内毒素和组胺对瘤胃上皮屏障功能的直接影响。与对照组（CON）相比，组胺（HIS，20 μM）增加了短路电流（Isc；88.2%，P < 0.01）、跨上皮电导（Gt；29.7%，P = 0.056）和荧光素 5（6）-异硫氰酸酯（FITC）的通透性（1.04 倍，P < 0.01）。LPS 的表观渗透率比 HIS 高 1.81 倍（P < 0.01）。瘤胃上皮中 OCLN 的 mRNA 丰度被 HIS 降低（1.1 倍，P = 0.047）。本研究结果表明，黏膜组胺直接参与了瘤胃上皮屏障功能的破坏，而脂多糖（在 pH 值为 7.4 时）对体外瘤胃组织的通透性没有影响。
