Direct effect of lipopolysaccharide and histamine on permeability of the rumen epithelium of steers ex vivo

• Published in: Journal of animal science Vol. 100; no. 2
• Main Authors: Gao, Shengtao, Zhula, Alateng, Liu, Wenhui, Lu, Zhongyan, Shen, Zanming, Penner, Gregory B, Ma, Lu, Bu, Dengpan
• Format: Journal Article
• Language: English
• Published: US Oxford University Press 01-02-2022
• Subjects: Animals; Diet; Epithelium; Gastrointestinal Biology; Histamine - pharmacology; Hydrogen-Ion Concentration; Lipopolysaccharides - pharmacology; Permeability; Rumen; subacute rumen acidosis; gastrointestinal tract; permeability
• ISSN: 0021-8812; 1525-3163
• DOI: 10.1093/jas/skac005

Abstract
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.
Lay Summary
Lipopolysaccharide and histamine are common chemicals in rumen when the ruminant animal takes too much concentrate. We wandered whether these two chemicals have direct effects on the rumen tissues. Using Ussing chamber, we found that histamine could directly improve the permeability of rumen barrier.
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.