Rice protein stimulates endogenous antioxidant response attributed to methionine availability in growing rats

Abstract

Methionine sulfoxide reductase (Msr) and glutathione (GSH) are two endogenous antioxidant systems for depressing oxidative stress. The aim of this study is to investigate the role of methionine in involving the stimulation of endogenous antioxidant capacity of rice protein (RP). Seven‐week‐old male Wistar rats (body weight 180–200 g) were fed with commercial pellets (as control), methionine, and RP for 2 weeks. Compared with control, GSH synthesis and expressions of MsrA, MsrB2, and MsrB3 were stimulated by methionine and RP. After 2 weeks of feeding, Nrf2 was activated by RP and methionine, whereas the expressions of Keap1 and Cul3 were depressed. The ARE‐driven antioxidant expressions (GCLC, GCLM, GS, HO‐1, NQO1, CAT, SOD, GR, GST, GPx) were upregulated by methionine and RP. Results suggest that the endogenous antioxidant response induced by RP is primarily attributed to the methionine availability, in which the stimulation of Msr and GSH antioxidant system via Nrf2‐ARE pathway. Practical applications Rice protein is a major plant protein, which is rich in sulfur‐containing amino acids and widely consumed in the world. This paper emphasizes that the amino acid plays a key role in inducing the antioxidant activity of rice protein. The present study provides an insight that the methionine availability of rice protein will be a useful target for health promoting by activating endogenous antioxidant response against ROS‐induced oxidative damage.

L-Methionine inhibits 4-hydroxy-2-nonenal accumulation and suppresses inflammation in growing rats

“…Sample collection followed the same protocol as in previous studies [ 17 18 22 23 24 ]. Briefly, at the end of the feeding period (14 days), the rats were fasted for 12 h before sample collection.…”

“…Quantitative real-time PCR was performed according to previous studies [ 17 18 22 23 24 ]. Briefly, the total RNA was extracted from a rat liver after 14 days of feeding using a TRIzol reagent kit (Invitrogen, Carlsbad, CA, USA) according to the manufacturer’s protocol.…”

“…Western blotting analysis followed the same protocol reported elsewhere [ 17 18 22 23 24 ]. Briefly, with equal amounts of protein, the samples of the total, cytoplasmic, and nuclear proteins were denatured by boiling for 5 min and separated by 10% SDS-PAGE.…”

“…Dietary antioxidants can suppress oxidative stress to decrease the formation of HNE, leading to a better understanding of how the dietary antioxidant plays a role in preventing HNE-derived inflammation. Methionine (Met) is an essential sulfur-containing amino acid that can regulate oxidative stress and lipid metabolism [ 15 16 17 18 19 20 ]. Wang et al .…”

l‐Arginine prevents 4‐hydroxy‐2‐nonenal accumulation and depresses inflammation via inhibiting NF‐κB activation

“…The animal study followed the same as our series of studies. [8,17,21] Animal experiments were permitted and conducted according to the Guidelines of the Committee for the Experimental Animals of Harbin Institute of Technology (Harbin, China).…”