Immunomodulatory effects of high-protein diet with resveratrol supplementation on radiation-induced acute-phase inflammation in rats.

Abstract

We hypothesized that a high-protein diet and/or resveratrol supplementation will

improve acute inflammatory responses in rats after receiving experimental

abdominal radiation treatment (ART). Based on our previous study, the period of

10 days after ART was used as an acute inflammation model. Rats were exposed to a

radiation dose of 17.5 Gy and were supplied with a control (C), 30% high-protein

diet (HP), resveratrol supplementation (RES), or HP with RES diet ([HP+RES]). At

day 10 after ART, we measured profiles of lipids, proteins, and immune cells in

blood. The levels of clusters of differentiating 4(+) (CD4(+)) cells and

regulatory T cells, serum proinflammatory cytokines, and

8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine were also measured. ART caused

significant disturbances of lipid profiles by increasing triglyceride (TG) and

low-density lipoprotein cholesterol (LDL-C), and decreasing high-density

lipoprotein cholesterol. The proinflammatroy cytokine levels were also increased

by ART. All the experimental diets (HP, RES, and [HP+RES]) significantly

decreased levels of TG, monocytes, proinflammatory cytokines, and 8-OHdG, whereas

the platelet counts were increased. In addition, the HP and [HP+RES] diets

decreased the concentrations of plasma LDL-C and total cholesterol. Also, the HP

and RES diets decreased regulatory T cells compared with those of the control

diet in ART group. Further, the HP diet led to a significant recovery of white

blood cell counts, as well as increased percentages of lymphocyte and decreased

percentages of neutrophils. In summary, RES appeared to be significantly

effective in minimizing radiation-induced damage to lipid metabolism and immune

responses. Our study also demonstrated the importance of dietary protein intake

in recovering from acute inflammation by radiation.