Effect Of Hydrolyzed Whey Protein On The Protein Nutritional Status And Antioxidant Capacity In Rats With Radiation Injury

ObjectiveWhey protein is a type of high-quality protein, which often serves as a source ofhigh-quality protein in therapeutical diet and tube feeding. Hydrolyzed whey protein (HWP)is produced after the enzymatic hydrolysis of whey protein. HWP contains small-molecularshort peptides and free amino acids which can be directly absorbed in the intestine withoutdigestion, thus having more biological activity than whey protein. In this paper, we studiedthe effect of HWP on the protein nutritional status and antioxidant capacity of rats withradiation injury, aiming to provide references for its clinical application.MethodsTotally40Sprague-Dawley rats (20males and20females,14weeks old, weighing269.7g±15.2g) were randomly divided into normal control group, experimental control group,experimental group Ⅰ, and experimental group Ⅱ (n=10). Whey protein was used as thenitrogen source in two control groups, while HWP was used in the other two groups.Meanwhile, rats in the experimental group Ⅱ were intragastricly administered10%SOD&selenium-enriched green tea solution every day. The other components in the fodder wereprepared by referring to the AIN-76and AIN-93formula. After5days of adaptive feeding inmetabolic cages, rats in the experimental control group, experimental group Ⅰ andexperimental group Ⅱ were all exposed to whole body irradiation of6Gy60Co gamma ray.Thereafter rats’ food intake was measured daily, weight was monitored regularly, and72-hourstool specimen was collected21days later. Blood samples were collected and then rats weresacrificed. Fecal nitrogen was determined and apparent protein digestibility (AD) wascalculated. Parameters including serum TP, ALB and MDA, as well as T-AOC, SOD andGSH-PX activities were detected. Besides, intestinal mucosa HE staining was performed. Results1. Rats in the normal control group presented normal food intake and a continuingincrease of body weight throughout the whole experimental period. However, the food intakeand body weight of the irradiated rats in the other three groups were significantly lower(P<0.01). Rats’ body weight in the experimental group Ⅰ and experimental group Ⅱ beganto increase at9and6days after irradiation respectively. And it was significantly higher inexperimental group Ⅱ than that in experimental control group (P<0.01) and experimentalgroup I (P <0.05).2. All the rats that received radiation presented a significantly higher fecal nitrogenoutput and lower AD value than those in normal control group (P<0.01). But compared withexperimental control group, fecal nitrogen output was much lower and AD value was muchhigher in the experimental groups Ⅰand Ⅱ (P<0.01).3. Serum TP and ALB levels were significantly lower in the experimental control groupthan in normal control group (P<0.01). The levels were also lower in experimental groupsⅠand Ⅱ, but only serum ALB revealed significant difference between experiment Ⅰ groupand normal control group (P<0.05). Moreover, the serum ALB content in the experimentalgroups Ⅰ and group II was significantly higher than that in the experimental control group(P<0.01).4. The activities of serum T-AOC, T-SOD and GSH-PX were remarkably lower in theexperimental control group than in the normal control group (P<0.01). Rats in theexperimental groupsⅠ and Ⅱ showed significantly lower activities of serum T-AOC andGSH-Px when compared with the normal control group (P<0.01), but significantly higherthan those in the experimental control group (P<0.01). Rats in the experimental group Ⅱindicated significantly higher serum GSH-PX activity when compared with the experimentgroup Ⅰ (P<0.01). The serum MDA content was much lower in the normal control groupcompared with other three groups (P<0.01), but the levels in experimental groups Ⅰ and Ⅱwere significantly lower than that in the experimental control group (P<0.01).5. The intestinal mucosa HE staining showed notable pathological changes in eachexperimental group. Conclusion1. whole body irradiation of6Gy60Co gamma ray can send the rats’ nutritional statebecome serious.2. HWP has a much better digestion, absorption and utilization than whey protein and itis more beneficial for improving the protein nutritional status of rats with radiation injury.3. HWP can reduce peroxidation injury of the irradiated rats, which may be related to itsintegrative biology effect. And the effect is more obvious when combined with selenium&SOD-enriched green tea powder.