Een obtained from uremic children in Iraq [27] and uremic adults in central Sudan [28]. The basis of this salutary effect of GA on renal function is probably an urea-lowering effect through utilizing the bowel as a “substitute kidney”, increasing urea nitrogen (N) excretion in stools, with a concomitant decrease in the total N excreted in urine [17,29,30]. Sorbents (such as resins) can augment hemodialysis systems by adsorbing/removing conventional uremic toxins such as urea and creatinine, and also other toxins [30]. It has also been shown that butyrate modifies the generation of the pro-fibrotic cytokine transforming growth factor-beta (TGF-b1) by renal epithelial cells, and that dietary supplementation with a naturally processed polysaccharide exudate from Acacia senegal can increase serum butyrate, which, at least in vitro, has beneficial effects on renal profibrotic cytokine generation [31]. In the present work, 1326631 we have extended our previous observations on the effects of GA treatment on rats with adenine nduced CRF [21], by investigating the anti-inflammatory and antioxidant mechanisms related to the protective effect of GA on adenineinduced CRF, using several novel parameters such as IL-10, as well as the generation of reactive oxygen species and DNA strand breaks. The results of our study will further explain the mechanisms of the beneficial effects of GA.Results Gum Arabic Ameliorates Adenine-induced 
Renal FailureIn the CRF model used in the present study, adenine is given mixed with the feed at a concentration of 0.75 , w/w, for 4 weeks. Orally administered adenine is metabolized to 2,8dihydroxyadenine, which precipitates and forms tubular crystals that injure the renal tissue. We could confirm here the previously reported effects [21,22] that adenine feeding (0.75 for 4 weeks) caused significant increases (P,0.001) in the concentrations of plasma creatinine and a significant decrease in the creatinine clearance (P,0.01) (Fig. 1). Treatment with GA significantly abated the adenine effect. As a further marker of kidney injury, proteinuria was analyzed (Fig. 1), showing a significant increase of excreted protein in adenine-treated rats, which was reduced significantly by GA, although not completely. Histopathological examination of the kidney revealed extensive signs of inflammation and fibrosis in kidneys of the adenine treated animals (Fig. 2 and Table 1), as well as glomerular damage (Table 1). GA significantly lowered this morphological damage (Table 1).Figure 1. Plasma creatinine (A) and creatinine clearance (B), as well as proteinuria (C) in control rats, rats treated with gum arabic (15 w/v in drinking water) and rats treated with adenine (0.75 w/w) alone in feed, or with adenine and gum arabic given concomitantly at the same dose for 28 days. Each column and vertical bar represents the mean 6 SEM (n = 6). ** p,0.01, *** p,0.001 vs. control, # p#0.05, ### p,0.001 vs. adenine treatment. doi:10.1371/journal.pone.0055242.gEffect of Gum Arabic on CRP and TNF-aCRP was significantly (P,0.05) decreased to about 51 in rats treated with adenine plus GA, when compared with rats treated with adenine alone (Fig. 3). The TNF-a concentration in urine and plasma was significantly increased in the adenine-treated group, and this increase was markedly and significantly diminished in rats treated with both adenine and GA (Fig. 4).Antioxidative Effects of Gum ArabicAs shown in Fig. 6A and B, superoxide formation was significantly high.