Effects of high protein feeding and insulin on liver antioxidant status in rats subjected to burn injury and hindlimb unloading (HU)

Previously, daily insulin (I) injection for 14 d had no significant effect on muscle wasting or liver antioxidant status in rats subjected to 40% TBSA burn (B) and HU. The present study investigated liver antioxidant status in the same model (B +HU and I for 14 d) but compared the responses in rats (n=6/gp) fed a 40% protein diet (HP+I), to rats fed a standard 20% protein diet (NP+I) for the 14 days. Responses were also compared to rats subjected to B and HU and fed the same protein diets, but did not receive I, or to uninjured animals fed the 20% diet (C). Total liver antioxidant potential was about 80% lower in all B+HU animals compared to C. In contrast, liver glutathione peroxidase activity was about 2 fold higher and xanthine oxidase activity was markedly higher in HP+I and NP+I rats compared to C, while glutathione reductase and Mn‐ SOD activities and GSH levels were significantly lower than C. Daily I injection for 14 d had no effect on antioxidant status at either level of protein intake. Also, no significant differences were observed in liver total antioxidant potential between burned rats fed either diet. These data suggest that B + HU for 14 days affected liver antioxidant status compared to normal controls, but neither insulin treatment nor high protein feeding could improve this response.