Effects of glucagon‐like peptides 1 and 2 and epidermal growth factor on the epithelial barrier of the rumen of adult sheep. Issue 6 (9th September 2019)

• Record Type: Journal Article
• Authors: Greco, Gabriele; Amasheh, Salah; Shen, Zanming; Lu, Zhongyan; Aschenbach, Jörg R.
• Is Part Of: Journal of animal physiology and animal nutrition. Volume 103:Issue 6(2019)
• Page Start: 1727
• Page End: 1738
• Publication Date: 2019-09-09
• Subjects: epidermal growth factor -- epithelial barrier -- glucagon‐like peptide -- rumen -- tight junction; Animal nutrition -- Periodicals; Feeds -- Periodicals; 636.085
• DOI: 10.1111/jpn.13200
• Languages: English
• ISSNs: 0931-2439

Abstract

Abstract: Epidermal growth factor (EGF) and glucagon‐like peptides (GLP) modulate the tight junctions (TJ) of the intestinal epithelial barrier (EB) of monogastric animals. This work tried to elucidate whether GLP‐1, GLP‐2 and EGF can affect the EB of the rumen. Ovine ruminal epithelia were incubated in Ussing chambers for 7 hr with 25 or 250 nM of either GLP‐1 or GLP‐2 on the serosal side, with 2.5 nM of EGF on the serosal side or with 0.25 or 2.5 nM EGF on the mucosal side. No treatment affected tissue conductance. Short‐circuit current ( I sc ) was affected by time and treatment and their interactions. Only 250 nM of either GLP‐1 or GLP‐2 decreased I sc in certain periods compared with 25 nM GLP‐1 or 0.25 nM mucosally applied EGF; however, not when compared to control epithelia. Fluorescein flux rates ( J fluor ) of ruminal epithelia were affected by treatment, time and time × treatment interaction. The time × treatment interaction was based on an increase in J fluor between the first and last hour in epithelia incubated with 25 nM GLP‐1 or GLP‐2 and in epithelia incubated with EGF. After 7 hr incubation, claudin‐7 mRNA expression was downregulated in all treatments. Claudin‐1 mRNA was upregulated after incubation with 2.5 nM EGF on the serosal side, claudin‐4 mRNA was downregulated by 2.5 nM EGF on the mucosal side, and occludin mRNA was increased after incubation with 250 nM GLP‐2. The protein abundance of all tested TJ proteins was not influenced by treatment. We conclude that GLP‐1, GLP‐2, and EGF have no obvious acute effects on the EB of ruminal epithelia under simulated physiological conditions ex vivo. However, by decreasing the mRNA expression of claudin‐7 and partly affecting other TJ proteins, they may modulate EB in the longer term or under certain conditions.