Nucleoside-nucleotide free diet protects rat colonic mucosa from damage induced by trinitrobenzene sulphonic acid.

Abstract

Background-Growing evidence suggests that intestinal recovery from injury induced by radiation, endotoxin, and protein deficiency is improved by the ingestion of nucleosides and nucleotides. Aim-This study examined the effect of dietary nucleosides and nucleotides supplementation on trinitrobenzene sulphonic acid induced colonic damage in experimental colitis. Methods-Sprague-Dawley rats were randomised into two groups and fed nucleic acid free 20% casein diet (control) or this diet supplemented with 0.5% nucleoside-nucleotide mixture for four weeks. On the second week, colonic inflammation was induced in rats by intracolonic administration of 0.25 ml of 50% ethanol containing 25 mg of trinitrobenzene sulphonic acid. Additionally, other sets of rats were treated with 0.25 ml of 50% ethanol, 25 mg of trinitrobenzene sulphonic acid in 0.25 ml saline, or 0.25 ml of 0.9% saline. Results-After two weeks, colon weight, macroscopic and microscopic damage scores, were significantly greater (p<0.05) in the nucleoside-nucleotide supplemented group compared with the nonsupplemented control groups. The same variables seen in the trinitrobenzene sulphonic acid-ethanol group fed nucleosidenucleotide free diet were greater (p<0.05) than in the rest of the groups fed nucleoside-nucleotide free diet and treated with ethanol, trinitrobenzene sulphonic acid in saline, or saline. Histologically, segmental ulceration and inflammation associated with significantly increased infiltration of polymorphonuclear leucocytes, macrophages, lymphocytes, fibroblasts were observed in the supplemented group compared with the controls. In the nucleoside-nucleotide supplemented group the epithelial damage, mucosal erosion, oedema, and coagulative necrosis of the muscularis propria was more extensive in comparison to the non-supplemented control groups. Conclusions-This study suggests that dietary nucleosides and nucleotides may aggravate colonic damage and inflammation in chemically induced experimental colitis in rats; and that nucleosidenucleotide free diet combined with other pharmacological agents may offer a better response.

P2X and P2Y purinergic receptors on human intestinal epithelial carcinoma cells: effects of extracellular nucleotides on apoptosis and cell proliferation

“…Taken together, these data agree with the functional data on nucleotide-mediated apoptosis, which revealed the presence of at least P2X 4 and P2X 7 and P2Y 1 and P2Y 2 receptors on the epithelial cell surface.…”

“…6, A-D, receptor protein expression was observed for most of the P2X receptors tested. In most experiments, P2X 4 and P2X 7 receptor immunostaining was stronger than for the other P2X subtypes. Thus, despite the low level of P2X 7 mRNA, a high level of P2X 7 receptor protein was found on HCT8 and Caco-2 cells.…”

“…Rabbit polyclonal antibodies against human P2X [1][2][3][4][5][6][7] (Roche Bioscience, Palo Alto, CA), P2Y1, P2Y2, and P2Y4 (Alomone Laboratories, Jerusalem, Israel) receptors were allowed to react with biotinylated donkey anti-rabbit IgG secondary antibody (Jackson Immunoresearch, West Grove, PA) and detected with either Oregon Green or avidin-coupled Texas Red (Sigma). Briefly, the slides were incubated overnight with primary antibodies diluted to 5 and 2.5 g/ml (determined as optimal by previous titration) with 10% NHS in PBS containing 0.05% Merthiolate and 0.1% saponin.…”

“…The synthesis of P2X receptor protein was then evaluated by immunofluorescence labeling, using polyclonal antibodies against P2X [1][2][3][4][5][6][7] . As shown in Table 1 and Fig.…”

“…The P2Y receptors are coupled to trimeric G proteins and are composed of eight subtypes in mammals (P2Y 1 , P2Y 2 , P2Y 4 , P2Y 6 , P2Y 11 , P2Y 12 , P2Y 13 , and P2Y 14 ) (1,12,33,39). The presence of P2Y 1 , P2Y 2 , P2Y 4 , and P2Y 6 receptors has been revealed in human airway epithelial model systems (54), and recently, it was shown that the P2Y 6 receptors mediate NaCl secretion in colonic epithelial cells (43).…”