Theanine attenuates hippocampus damage of rat cerebral ischemia-reperfusion injury by inhibiting HO-1 expression and activating ERK1/2 pathway.

Abstract

AIMS:

Theanine, as a naturally occurring component in tea, has been shown to deliver benefits against various diseases. However, the exact molecular mechanisms underlying theanine's protective actions against cerebral ischemia/reperfusion (IR) injury still remains largely unknown.

MAIN METHODS:

In this study, rat cerebral IR injury model was established and were randomly divided into the following five groups: Sham (SH), IR, IR + Theanine (TH), IR + TH+ heme oxygenase-1 (HO-1) inducer cobalt protoporphyrin (Copp), and IR + Copp groups.

KEY FINDINGS:

We found that theanine significantly inhibited neuron damage and apoptosis in the hippocampus during the 48 h detection period, as detected by hematoxylin and eosin (HE) and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Meanwhile, reduced levels of malondialdehyde (MDA) and elevated activities of superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GSH-PX) were observed in the theanine-treated group. Enzyme-linked immunosorbent (ELISA) assay also revealed that theanine markedly decreased the levels of inflammatory cytokines, such as IL-6, IL-1β, and TNF-α, in IR rats. The anti-apoptotic effect of theanine on IR injury was further verified by flow cytometry assay. Besides, theanine dramatically inhibited HO-1 expression and activity but increased extracellular signal-regulated kinase 1/2 (ERK1/2) activity in hippocampal tissue from rats with cerebral IR injury. However, co-treatment with Copp remarkably abolished the protective effects of theanine on cerebral IR injury.

SIGNIFICANCE:

These findings demonstrated that the neuroprotective role of theanine was associated with its anti-oxidative, anti-inflammatory, and anti-apoptotic properties, which might be through regulation of HO-1 activation in rats with cerebral IR injury.

• Authors: Jing Zhao, Xiayong Zhao, Junbin Tian, Rongliang Xue, Bin Luo, Jianrui Lv, Jing Gao, Mei Wang
• Journal: Life sciences (Life Sci) Vol. 241 Pg. 117160 (Jan 15 2020) ISSN: 1879-0631 [Electronic] Netherlands
• PMID: 31837331 (Publication Type: Journal Article)
• Copyright: Copyright © 2019 Elsevier Inc. All rights reserved.

Chemical References

• Glutamates
• theanine
• Heme Oxygenase (Decyclizing)
• Hmox1 protein, rat

Topics

• Animals
• Apoptosis (drug effects)
• Brain Ischemia (etiology, metabolism, pathology, prevention & control)
• Gene Expression Regulation (drug effects)
• Glutamates (pharmacology)
• Heme Oxygenase (Decyclizing) (antagonists & inhibitors)
• Hippocampus (drug effects, metabolism, pathology)
• Inflammation (drug therapy, metabolism, pathology)
• MAP Kinase Signaling System (drug effects)
• Male
• Neurons (drug effects, metabolism, pathology)
• Oxidative Stress (drug effects)
• Rats
• Rats, Sprague-Dawley
• Reperfusion Injury (etiology, metabolism, pathology, prevention & control)