Rice protein improves oxidative stress by regulating glutathione metabolism and attenuating oxidative damage to lipids and proteins in rats.
OBJECTIVE
To evaluate the effects of rice protein (RP) on glutathione metabolism and oxidative damage.


METHODS
Seven-week-old male Wistar rats were fed diets containing casein and RP without cholesterol for 3weeks. Plasma and liver lipid levels, hepatic accumulation of total glutathione (T-GSH), oxidized glutathione (GSSG), reduced glutathione (GSH), malondialdehyde (MDA) and protein carbonyl (PCO) were measured. In the liver, the total antioxidative capacity (T-AOC), mRNA levels of glutamate cysteine ligase catalytic subunit (GCLC) and glutamate cysteine ligase modulatory subunit (GCLM), and the activities of hepatic catalase (CAT), total superoxide dismutase (T-SOD), γ-glutamylcysteine synthetase (γ-GCS), glutathione S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GSHPx) were also measured.


RESULTS
T-AOC, GCLC and GCLM mRNA levels, antioxidative enzyme activities (T-SOD and CAT) and glutathione metabolism related enzyme activities (γ-GCS, GST, GR and GSHPx) were effectively stimulated by RP feeding compared to casein, and RP significantly reduced the hepatic accumulation of MDA and PCO in rats. These results indicate that lipid-lowering activity was induced by RP feeding.


CONCLUSIONS
The present study demonstrates that RP improves oxidative stress primarily through enzymatic and non-enzymatic antioxidative defense mechanisms, reflected by enhancing the antioxidative status and attenuating the oxidative damage to lipids and proteins. These results suggest that RP can prevent hyperlipidemia in part through modifying glutathione metabolism, and sulfur amino acids may be the main modulator of this antioxidative mechanism.
School of Food Science and Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China. Electronic address: ly6617@hit.edu.cn.
Lin
L
Yang
Heilongjiang Provincial Environmental Monitoring Central Station, Harbin 150056, China.
Jia-Hou
JH
Chen
Heilongjiang Provincial Hospital, Harbin 150036, China.
Tong
T
Xu
Heilongjiang Provincial Environmental Monitoring Central Station, Harbin 150056, China.
Ai-Shen
AS
Zhou
Heilongjiang Provincial Environmental Monitoring Central Station, Harbin 150056, China.
Hong-Kun
HK
Yang
D000818:Animals; D002374:Catalase / Q000032:analysis; D005721:Glutamate-Cysteine Ligase / Q000032:analysis; D005978:Glutathione / Q000097:blood / Q000737:chemistry / Q000378:metabolism*; D005979:Glutathione Peroxidase / Q000032:analysis; D005980:Glutathione Reductase / Q000032:analysis; D005982:Glutathione Transferase / Q000032:analysis; D015227:Lipid Peroxidation / Q000187:drug effects*; D008099:Liver / Q000737:chemistry; D008297:Male; D008315:Malondialdehyde / Q000032:analysis; D012275:Oryza; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects*; D014674:Plant Proteins, Dietary / Q000494:pharmacology*; D050050:Protein Carbonylation / Q000187:drug effects; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000032:analysis
D014674:Plant Proteins, Dietary; D011506:Proteins; D008315:Malondialdehyde; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005982:Glutathione Transferase; D005721:Glutamate-Cysteine Ligase; C544143:GCLC protein, rat; D005978:Glutathione