Protective Effect of Quercetin on the Brain of Neisseria Meningitides-infected Rats
Objective:To investigate the protective effect of quercetin(Que)on the brain tissue of rats with Neisseria meningitidis and its mechanism.Methods:All 180 SD rats were randomly divided into normal control group,model group,ampicillin(AMP group,200 mg/kg)group,low(50 mg/kg),medium(100 mg/kg),and high(200 mg/kg)dosage groups of Que,with 30 rats in each group.Except for the normal control group,the rat model of meningitis was prepared by injecting Neisseria suspension into the small medulla oblongata pool in all groups.After modeling,each group was administered(AMP by subcutaneous injection,Que administered by gavage)once every 12 h for a total of five times.To perform symptom scoring after collecting survival rates of rats in each group,to detect blood-brain barrier(BBB)permeability using Evans blue penetration method,to carry out brain tissue pathological examination using HE staining method,and to detect the contents of plasma lipopoly-saccharide(LPS)and tumor necrosis factor-α(TNF-α),Interleukin-1 β(IL-1β)and Interleukin-6(IL-6)in brain tissue using ELISA method,to measure the contents of malondialdehyde(MDA),the activity of superoxide dismutase(SOD)and catalase(CAT)using biochemical analysis,and Western blot was used to measure the expressions of p65,Iκ B α and HMGB1 protein in brain tissue.Results:Compared with the model group,the survival rates of rats in the AMP group,medium and high dose groups of Que were higher,the symptom scores and Evans blue infiltration were lower(P＜0.01);the pathological changes of brain tissues were improved;the contents of plasma LPS,the levels of TNF-α,IL-1β,IL-6 and MDA were lower,and the activities of SOD and CAT were higher(P＜0.05 or P＜0.01);the relative expressions of p65 and HMGB1 were decreased while the relative expression of IκBα was increased(P＜0.01).Compared with the AMP group,rats in the high-dose group of Que showed the noticeably higher survival rate,the lower symptom scores and Evans blue infiltration(P＜0.05 or P＜0.01);lower contents of plasma LPS and reduced contents of TNF-α and MDA in brain tissue,and higher activity of SOD(P＜0.05 or P＜0.01);and the relative expressions of p65 and HMGB1 were decreased and the relative expression of IκBα was increased(P＜0.05 or P＜0.01).Conclusion:Que could reduce the inflam-matory response and oxidative stress damage in brain tissue by lowering the level of LPS,inhibiting the NF-κB inflammatory pathway,down-regulating the expression of HMGB1,and improving the activity of antioxidant enzymes,and then protect the brain tissue of Neisserococcus meningitis rats.
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万方数据
维普
