Dietary L-arginine supplementation reduces Methotrexate-induced intestinal mucosal injury in rat

<p>Abstract</p> <p>Background</p> <p>Arginine (ARG) and nitric oxide maintain the mucosal integrity of the intestine in various intestinal disorders. In the present study, we evaluated the effects of oral ARG supplementation on intestinal structural changes, enterocyte proliferation and apoptosis following methotrexate (MTX)-induced intestinal damage in a rat.</p> <p>Methods</p> <p>Male rats were divided into four experimental groups: Control rats, CONTR-ARG rats, were treated with oral ARG given in drinking water 72 hours before and 72 hours following vehicle injection, MTX rats were treated with a single dose of methotrexate, and MTX-ARG rats were treated with oral ARG following injection of MTX. Intestinal mucosal damage, mucosal structural changes, enterocyte proliferation and enterocyte apoptosis were determined 72 hours following MTX injection. RT-PCR was used to determine bax and bcl-2 mRNA expression.</p> <p>Results</p> <p>MTX-ARG rats demonstrated greater jejunal and ileal bowel weight, greater ileal mucosal weight, greater ileal mucosal DNA and protein levels, greater villus height in jejunum and ileum and crypt depth in ileum, compared to MTX animals. A significant decrease in enterocyte apoptosis in the ileum of MTX-ARG rats (vs MTX) was accompanied by decreased bax mRNA and protein expression and increased bcl-2 protein levels.</p> <p>Conclusions</p> <p>Treatment with oral ARG prevents mucosal injury and improves intestinal recovery following MTX- injury in the rat.</p

The Mechanisms of the Anti-Inflammatory and Anti-Apoptotic Effects of Omega-3 Polyunsaturated Fatty Acids during Methotrexate-Induced Intestinal Damage in Cell Line and in a Rat Model

Background: The aim of this study was to examine the anti-inflammatory and anti-apoptotic patterns of omega-3 polyunsaturated fatty acids (n-3 PUFAs) during methotrexate (MTX) induced intestinal damage in cell culture and in a rat model. Methods: Non-treated and treated with MTX HT 29 and HCT116cells were exposed to increasing doses of n-3 PUFAs and cell viability was evaluated using PrestoBlue® assay. Male Sprague-Dawley rats were divided into 4 experimental groups: Control rats, CONTR+n-3 PUFA rats that were treated with oral n-3 PUFA, MTX rats were treated with MTX given IP, and MTX+n-3 PUFA rats were treated with oral n-3 PUFA before and following injection of MTX. Intestinal mucosal parameters and mucosal inflammation, enterocyte proliferation and apoptosis, TNF-α in mucosal tissue and plasma (ELISA), NF-κB, COX-2, TNF-α, Fas, FasL, Fadd, Bid, Bax and Bcl-2gene and protein levels were determined 72 h following MTX injection. Results: Exposure of HT 29 and HCT116cells to n-3 PUFA attenuated inhibiting effects of MTX on cell viability. MTX-n-3 PUFA rats demonstrated a lower intestinal injury score and enhanced intestinal repair. A significant decrease in enterocyte apoptosis in MTX+n-3 PUFA rats was accompanied by decreased TNF-α, FAS, FasL, FADD and BID mRNA levels. Decreased NF-κB, COX-2 and TNF-α levels in mucosa was accompanied by a decreased number of IELs and macrophages. Conclusions: n-3 PUFAs inhibit NF-κB/COX-2 induced production of pro-inflammatory cytokines and inhibit cell apoptosis mainly by extrinsic pathway in rats with MTX-induced intestinal damage