N used chemically induced experimental animal model for CKD. Inflammation and oxidative stress in this experimental model, introduced three decades ago [35] have, as far as we are aware, not been studied in detail before. More is known about the involvement of oxidative stress and inflammation in the RKM model, as demonstrated by Kim et al. [36] for example. In the present study, as in our previous work, adenine treatment induced all the classical signs of renal impairment reported earlier [21,22]. For brevity, in thiswork we reported the effects of adenine on plasma creatinine, creatinine clearance, and proteinuria. GA has been shown to act as an antioxidant, and to modulate inflammatory and/or immunological processes [17]. For example, the cytoprotective effects of GA against cisplatin-induced nephrotoxicity and cyclophosphamide-induced urinary bladder cytotoxicity in rats have been ascribed to a scavenging action against reactive oxygen metabolites [37,38]. GA has also been reported to have a partial ameliorating action against experimental gentamicin-induced nephrotoxicity in rats [39]. In the present work, we tested in renal tissue, plasma and urine of rats, the effect of GA treatment (15 in the Thiazole Orange drinking water for 4 weeks) on several established inflammatory and oxidative stress markers in rats with adenine nduced CRF. It is known that samples of different GA products can be inherently variable, depending on their sources and location. Here, we have used an Acacia senegal var. senegal sample, which has been 
matured to yield a standardized and reproducible test material, with a known molecular weight [31]. As a sign of inflammation, tissue infiltration of white blood cells was observed at histopathological examination of kidneys of adenine-treated animals, which was significantly suppressed in animals treated with adenine together with GA. CRP is an acute phase reactant that is increased in inflammation and infection, and has long been used as a biomarker indicating these conditions [40]. It has been shown to be increased in 
plasma of RKM rats [41]. Our results show that coadministration of GA to adenine-treated rats resulted in aFigure 3. Plasma C-reactive protein concentration in control rats, rats treated with gum CP21 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#0.05 vs. adenine treatment. doi:10.1371/journal.pone.0055242.gGum Arabic and Adenine Chronic Renal FailureFigure 5. Interleukin 10 (IL-10) concentration in the plasma of 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,0.001 vs. control, ### p,0.001 vs. adenine treatment. doi:10.1371/journal.pone.0055242.gFigure 4. Tumor necrosis factor-a concentration in urine (A) and plasma (B) 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,0.01,### p,0.001 vs. adenine treatment. doi:10.1371/journ.N used chemically induced experimental animal model for CKD. Inflammation and oxidative stress in this experimental model, introduced three decades ago [35] have, as far as we are aware, not been studied in detail before. More is known about the involvement of oxidative stress and inflammation in the RKM model, as demonstrated by Kim et al. [36] for example. In the present study, as in our previous work, adenine treatment induced all the classical signs of renal impairment reported earlier [21,22]. For brevity, in thiswork we reported the effects of adenine on plasma creatinine, creatinine clearance, and proteinuria. GA has been shown to act as an antioxidant, and to modulate inflammatory and/or immunological processes [17]. For example, the cytoprotective effects of GA against cisplatin-induced nephrotoxicity and cyclophosphamide-induced urinary bladder cytotoxicity in rats have been ascribed to a scavenging action against reactive oxygen metabolites [37,38]. GA has also been reported to have a partial ameliorating action against experimental gentamicin-induced nephrotoxicity in rats [39]. In the present work, we tested in renal tissue, plasma and urine of rats, the effect of GA treatment (15 in the drinking water for 4 weeks) on several established inflammatory and oxidative stress markers in rats with adenine nduced CRF. It is known that samples of different GA products can be inherently variable, depending on their sources and location. Here, we have used an Acacia senegal var. senegal sample, which has been matured to yield a standardized and reproducible test material, with a known molecular weight [31]. As a sign of inflammation, tissue infiltration of white blood cells was observed at histopathological examination of kidneys of adenine-treated animals, which was significantly suppressed in animals treated with adenine together with GA. CRP is an acute phase reactant that is increased in inflammation and infection, and has long been used as a biomarker indicating these conditions [40]. It has been shown to be increased in plasma of RKM rats [41]. Our results show that coadministration of GA to adenine-treated rats resulted in aFigure 3. Plasma C-reactive protein concentration 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#0.05 vs. adenine treatment. doi:10.1371/journal.pone.0055242.gGum Arabic and Adenine Chronic Renal FailureFigure 5. Interleukin 10 (IL-10) concentration in the plasma of 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,0.001 vs. control, ### p,0.001 vs. adenine treatment. doi:10.1371/journal.pone.0055242.gFigure 4. Tumor necrosis factor-a concentration in urine (A) and plasma (B) 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,0.01,### p,0.001 vs. adenine treatment. doi:10.1371/journ.
