Preventive effects of guanosine on intestinal inflammation in 2, 4-dinitrobenzene sulfonic acid (DNBS)-induced colitis in rats

Background: Guanosine, a guanine-based purine, is an extracellular signaling molecule exerting anti-inflammatory and antioxidative effects in several in vivo and in vitro injury models. We aimed to investigate its protective effects on 2, 4-dinitrobenzene sulfonic acid (DNBS)-induced colitis in rat. Methods: Rats were divided into five groups and colitis was induced by intracolonic instillation of DNBS (15 mg/rat). Guanosine (4 or 8 mg/kg) was administered for 6 days i.p. starting the day of the colitis induction. Body weight loss, stool consistency, colon weight/length, histological analysis, myeloperoxidase activity (MPO) and pro-inflammatory cytokine levels were assessed. Immunoblotting of nuclear factor-κB (NF-κB) p65 protein levels and detection of oxidative and nitrosative stress markers were also performed. Results: Guanosine, in a dose-dependent manner, significantly ameliorated the severity of DNBS-induced colitis, reducing body weight loss and diarrhea incidence, preventing the DNBS-induced macroscopic and microscopic damage to the colonic mucosa, and the MPO increase. Guanosine treatment also lowered interleukin-1β, interleukin-6, and tumor necrosis factor-α mRNA levels. Importantly, guanosine in DNBS rats down-regulated the expression of NF-κB p65 and the levels of reactive oxygen species and nitrite. Conclusions: In conclusion, guanosine exerts beneficial effects in DNBS-induced colitis in rats, through modulation of colonic inflammation, downregulating of NFκB-mediated signaling.