Mitigation of indomethacin-induced gastrointestinal damages in fat-1 transgenic mice via gate-keeper action of ω-3-polyunsaturated fatty acids.

Young-Min Han,Migeyong Jeong,Ji-Young Cha,Ki Baik Hahm,Ho-Jae Lee,Eun-Jin Go,Jong-Min Park,Jing X Kang

doi:10.1038/srep33992

Abstract

Non-steroidal anti-inflammatory drugs (NSAIDs) damage the gastrointestinal (GI) epithelial cell membranes by inducing several signals through lipid raft organization after membrane incorporation, whereas ω-3 polyunsaturated fatty acids (PUFAs) relieve inflammation, reduce oxidative stress, and provide cytoprotection, consequent to lipid raft disorganization. Therefore, we hypothesized that ω-3 PUFAs can protect the GI from NSAID-induced damages by initiating the gatekeeper action of cell membranes, subsequent to anti-inflammatory and anti-oxidative actions. Administration of indomethacin (IND) leads to the formation of lipid rafts and activation of caveolin-1; however, no such observations were made upon co-administration of eicosapentaenoic acid (EPA) and IND. In addition, the EPA-induced lipid raft disorganization, caveolin-1 inactivation, and cellular cytotoxicity were inhibited when target cells were knocked-out using G-protein coupled receptor 120 (GPR 120). EPA significantly attenuated IND-induced oxidative damage and apoptosis. IND administration induced significant ulceration, bleeding, and oedema in the stomach or small intestine of wild-type (WT) mice; however, such severe damages to the GI significantly decreased in fat-1 transgenic (TG) mice (P < 0.001), which exhibited decreased cyclooxygenase-2 expression and apoptosis, decreased interleukin-1β and FAS concentrations, and increased heme oxygenase-1 concentration. Our study indicates that the gatekeeper function of ω-3 PUFAs improves GI safety when administered with NSAID.

Highlights

The ω-3 PUFAs have already been reported to stabilize the membrane by modifying membrane structure, disturbing membrane lipid raft organization, and inactivating cell signalling relevant to apoptosis[7]
To validate the direct cytotoxicity of NSAIDs18,19, scanning electron microscopy (SEM), which is a type of electron microscope that produces images of a sample by scanning it with focused beam of electrons, was performed 16 hr after IND administration and Fig. 1a shows that IND (500 μM, 16 hr) exposure led to overt cell damage such as cell surface blebs, membrane pore formation, and basement membrane detachment
Figure. 1a shows cross-linked monosialotetrahexosylganglioside (GM1) lipid micro-domains on the surface of RGM-1 cells; the domains are visualized with cholera toxin subunit B (CTB)-FITC

Summary

Introduction

The ω-3 PUFAs have already been reported to stabilize the membrane by modifying membrane structure, disturbing membrane lipid raft organization, and inactivating cell signalling relevant to apoptosis[7]. To clarify the core proteomes involved in either IND-induced gastric damage or the preventative effects of ω- 3 PUFAs in fat-1 TG mice, we performed a cytokine antibody array using homogenated proteins isolated from the stomach of WT and fat-1 TG mice (Fig. 4b).

Results

Conclusion