The Protective Effect Of Rice Bran Active Peptide On Oxidative Stress In D-galactose-induced Aging Mice

Rice is not only one of the most important staple foods in China.Rice bran,the by-product of deep processing of rice which are rich in protein can be converted into various biologically active ingredients by means of reasonable processing.In the early stage,our group has extracted several active peptides from rice bran protein,and has evaluated their ability to scavenge free radicals in vitro.After multiple comparisons,the active peptides with the highest antioxidant activity were screened for further research.In the early stage of this experiment,it has been proved that rice bran active peptides have certain anti-oxidative protective effect on endothelial cells.According to this,this paper studies the protective effects of rice bran active peptides(RBAP)on oxidative stress in vivo and their possible mechanism based on the oxidation model of D-galactose-induced mouse senescence and C.elegans.It lays a theoretical foundation for the further development and utilization of RBAP,and also provides a reference for the continuous value-added utilization of rice processing by-products,and further supports the development of RBAP as special medical foods.In this paper,we establishing the mouse oxidative stress model by subcutaneous injection of D-gal 250 mg/kg·d.In RBAP protection group,mice simultaneously were administered rice bran active peptide of 30mg/kg·d for 12 weeks.The contents of ROS,8-OHDG,MDA and the levels of SOD and GSH-Px in serum were determined.The pathological sections of aorta and brain were made,and the morphological features was observed after H&E staining.The protein expression of oxidative stress in liver homogenate,inflammation and apoptosis pathways in each group were determined by Western blot.The expression levels of genes regulating major proteins on related pathways were analyzed by RT-qPCR.After the protective effects of RBAP on oxidative stress in higher animals has been evaluated,the C.elegans model was used to evaluate whether rice bran active peptide has the same protective effects on lower animals.By means of protecting natural senescent Caenorhabditis elegans with different concentration(0.01M,0.03M and 0.1M)of RBAP and detecting the lifespan,reproductive ability,athletic ability,MDA content and activity of antioxidant enzymes of nematodes.The results showed that the RBAP can clear the expression of D-gal-induced oxidative stress injury markers,ROS,8-OHDG and MDA.RBAP can up-regulate the expression of SOD and GSH-Px,which preliminarily demonstrated that RBAP had protective effects against D-gal-induced oxidative stress in mice.RBAP can alleviate D-galactose-induced damage of mice aortic morphology,protect thinned arterial wall and reduce the number of ruptured endothelial cells.Pathological sections of brain tissue showed rice bran active peptide can protect the morphology of cerebral cortical neurons and cone cells in the hippocampal CA1 region.It was determined that the RBAP had an antioxidant effect on D-galactose-induced aging mice at the biochemical level.RBAP can up-regulate the pathway of keap1/Nrf2/HO-1,enhance the body's antioxidant capacity,inhibit the phosphorylation of p38 MAPK and JNK MAPK which can down-regulate the expression of apoptosis-related factors BCL2 and caspase3 and down-regulate the pathway of NF-?B to release inflammatory factors.RBAP can prolong the average life span of Caenorhabditis elegans,At the biochemical level,the content of MDA was reduced by the addition of RBAP;at the enzyme level,RBAP can improve the activity of antioxidant enzymes,such as SOD and GSH-Px.In general,rice active peptide can alleviate oxidative stress status in the body of D-galactose aging mice.Its mechanism may be related to up-regulating the pathway of Nrf2/HO-1 by rice bran active peptide,inhibiting the phosphorylation of p38 MAPK and JNK MAPK,further down-regulating the expression of apoptosis-related factors of BCL2 and caspase3,and decreasing the releasing of inflammatory factors.Moreover,rice bran active peptides can slow down the oxidative stress in the natural aging of C.elegans,prolong its life span and enhance its antioxidant capacity.Whether the mechanism of it and action mechanism of rice bran active peptide in mice are similar needs further discussion.