Effect of vitexin on Nrf2/ARE pathway in alleviating oxidative stress in rats with acute cerebral ischemia-reperfusion / 中草药

ABSTRACT

Objective: To investigate the effect of vitexin on oxidative stress in rats with acute cerebral ischemia-reperfusion by regulating the pathway of nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE). Methods: A total of 54 SD rats were randomly divided into Sham group, model group, positive control (edaravone 0.56 mg/kg) group and vitexin low, medium, and high dose (10, 20, 40 mg/kg) groups. The rat models with acute cerebral ischemia were established except the Sham group. After reperfusion, rats in Sham group and model group were received ip saline. The edaravone group and vitexin groups were administered according to the corresponding dose, once every 8 h for a total of three times. The neurobehavioral scores of rats before and after intervention were compared. HE staining was used to detect the pathological changes of cerebral cortex. The levels of MDA, NO, SOD, and GSH in cerebral cortex of rats were detected by the kit. The mRNA and protein expression levels of Nrf2/ARE pathway related gene in rat cerebral cortex were detected by real-time fluorescent quantitative PCR (qRT-PCR) and Western blotting. Results: Before and after intervention, there was no significant change in the neurobehavioral score of rats in the Sham group, the model group was higher than before intervention (P < 0.01), the edaravone group and the vitexin groups were lower than before intervention (P < 0.01), and there was a significant difference in the neurobehavioral score between the groups after intervention (P < 0.01). In the Sham group, the distribution of nerve cells was uniform and dense, and the morphology of cell body and nucleus was normal. In the model group, edaravone group and vitexin group, the arrangement of brain tissue was disordered and loose, in which liquefying necrosis and disappearance of cell structure were observed in the model group; in the low-dose group, the arrangement of cells was seriously disordered and loose. In the vitexin medium dose group and edaravone group, the area of liquefying necrosis was small, and most of the cells were normal; In the vitexin high dose group, only a few liquefying necrosis were found, the cell structure was basically normal, and the cell arrangement was slightly disordered. Compared with the Sham group, the levels of MDA and NO in the cerebral cortex of the model group were significantly increased (P < 0.01), the levels of SOD and GSH were significantly reduced (P < 0.01), and the expression levels of Nrf2 and γ-GCS mRNA were significantly increased (P < 0.01), the expression of cytoplasmic Nrf2 and γ-GCS proteins were significantly increased (P < 0.01), and the expression levels of nuclear Nrf2 and HO-1 proteins were significantly decreased (P < 0.01). Compared with the model group, the levels of MDA and NO in the cerebral cortex of rats in the edaravone group and low, medium and high dose groups of vitexin were significantly reduced (P < 0.01), and the levels of SOD and GSH were significantly increased (P < 0.01), Nrf2 and γ-GCS mRNA expression levels were significantly reduced (P < 0.01), cytoplasmic Nrf2, γ-GCS protein expressions were significantly reduced (P < 0.01), and nuclear Nrf2 and HO-1 protein expression levels were significantly increased (P < 0.01). And the levels of MDA, NO, SOD, GSH and Nrf2, γ-GCS, HO-1 mRNA and protein expression in rat cerebral cortex in each dose group were dose-dependent, with significant differences between groups (P < 0.01). Conclusion: Vitexin can alleviate oxidative stress in rats with acute cerebral ischemia-reperfusion. It is speculated that it is related to the regulation of Nrf2/ARE signaling pathway, the up-regulation of Nrf2 gene and protein expression, the promotion of its movement from cytoplasm to nucleus, the up-regulation of HO-1 expression, the inhibition of γ-GCS expression, and the enhancement of the body’s ability to response to oxidative stress.