| Summary: | 碩士 === 臺北醫學大學 === 保健營養學研究所 === 97 === Arginine (Arg) has been shown to have immunomodulatory effect and inhibits advanced glycation end products (AGEs) formation in in vitro and in vivo studies. However, the effects of dietary Arg supplementation on the expression of inflammatory mediators and renal receptor of AGE (RAGE) in diabetic rats are still unclear. In the present study, normal control (NC) group and two diabetic groups are involved. Rats in NC groups were fed with chow diet. One diabetic group (DM) was fed a common semipurified diet whereas the other diabetic group received an identical diet except that part of the casein was replaced by Arg (DM-Arg), which provided 2% of the total energy intake. Diabetes was induced by intraperitoneal injection of nicotinamide followed by streptozotocin. Rats with blood glucose levels exceeding 180 mg/dl were considered diabetic. Blood samples were collected at baseline, 4 wk, and 8 wk. Rats were sacrificed at the end of 8 wk. The kidneys of the animals were harvested at the end of the study for further analysis. The results showed that plasma C-reactive protein (CRP), monocyte chemotactic protein (MCP)-1, prostaglandin (PG)E2 and fructosamine levels were significantly higher in the diabetic groups than those in the NC group (p < 0.05). No differences in plasma MCP-1 and PGE2 levels were found between the DM and DM-Arg groups. However, CRP, fructosamine were significantly lower in DM-Arg group than in DM group (CRP: 33.2 ± 4.7 vs. 37.6 ± 4.2 mg/dl, p < 0.05; fructosamine: 0.16 ± 0.02 vs. 0.19 ± 0.02 ΔA/3min, p < 0.001). Kidney nitrotyrosine concentrations and nuclear factor-kappa B p65 protein expressions were significantly lower in DM-Arg group than in DM group (Nitrotyrosine: 176 ± 26 vs. 199 ± 21 nM, p < 0.05). The result of immunohistochemistry stain also showed that the expressions of RAGE in kidney were significantly lower in DM-Arg group than in DM group (33.6 ± 0.4 vs. 42.3 ± 0.4 μm2, p < 0.05). These results suggest that dietary Arg supplementation may decrease AGE formation and ameliorate renal damage in rats with type 2 diabetes.
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