The Regulation Of Nrf2/Bach1 On γ-glutamylcysteine Synthetase In The Course Of Bronchial Asthma

English AbstractBackgroundγ-Glutamylcysteine synthetase(γ-GCS) , as the rate-limiting enzyme in the synthensis of glutathione(GSH), is a vital antioxidase. Studys in vitro showed that NF-E2 related factor 2(Nrf2) in nuclear can up-regulate the expression of antioxidase,while the BTB and CNC homology 1(Bach1)can down-regulate its expression. Previous studies in our laboratory have shown that cigarette smoke extractant may promotes the nuclear translocation of Nrf2 and up-regulates the expresssion ofγ-GCS in airway epithelium in vitro culture.Objective: To investigate the mechanisms that Nrf2/Bach1 regulates the expressson ofγ-GCS in whole level and the effect of that in pathogenesis of bronchial asthma.Methods: The whole experiment was divided into tow parts, animal research and clinic research.38 healthy adult male guinea pigs were randomly divided into control group (group A), asthmatic group (group B) and dexamethasone group(group C) . Asthmatic model was established through ovalbumin challenge method. The malondialdehyde concentration of the lung tissue homogena was detected in three groups.The mRNA and protein expression of Bach1,Nrf2 andγ-GCS in lung tissue and cells of bron??lveolar lavage fluid(BALF) were measured.Clinic research was included three groups, healthy control group, asthma group, treatment group.Pulmonary function test was carried out in each group. The protein and mRNA expression of Nrf2, Bach1 andγ-GCS in cells in sputum from each group were measured.Results :(1)The malondialdehyde concentration (nmol/mg.prot)of lung tissue from guinea pigs in group B was significantly higher than that in group A and group C(P<0.05). The concentration of malondialdehyde(nmol/mg.prot) in blood plasm from asthmatic patient was signifcantly higher than that in healthy control group and treatment group(P<0.01).(2)The expression ofγ-GCS mRNA in group B was significantly lower than that in group A and group C(P<0.05). But the mRNA ecpression Nrf2 and Bach1 had no significant difference among the three groups.(3)The expression ofγ-GCS protein in group B was lower than that in on group A and group C(P <0.01), and the expression of Nrf2 protein in cell nucleus in group B significantly was lower than those in group A and group C. But the expression of Bach1 in cell nucleus in groupB was higher than those in group A and group C(P<0.01).(4)The expression ofγ-GCS mRNA and protein in cells in sputum from asthmatic patient after treatment were significantly higher than that before treatment(P <0.01) ,and the expression of Nrf2 protein in cell nuclus after treatment than that before treatment(P <0.01).But expression of Bach1 in cell nuclus after treatment was significantly lower than that before treatment(P <0.01).(5)There was a positive correlation between the cellular expression ofγ-GCS mRNA a??he expression of Nrf2 in cell nuclus in lung tissue from guinea pigs, cells of BALF and cells in sputum from asthmatic patients, but a negtive correlation between the cellular expression ofγ-GCS mRNA and the expression of Bach1 in cell nuclus in lung tissue from guinea pigs, cells of BALF and cells in sputum from asthmatic patients.Conclusions: The disequilibrium of oxidation/antioxygen plays a key role in the pathogenesis of bronchial asthma.γ-GCS can reduce oxidative damage of parasitifer. The expression ofγ-GCS may be regulated by levels of Nrf2 and Bach1 in nuclus ,while it is no direct correlation between expression ofγ-GCS and mRNA expression of Nrf2 and Bach1. The capability of anti-oxidation of guinea pigs and asthmatic patient being increased by anti-inflammatory treatment may be due to regulating Nrf2/Bach1 nuclear translocation and increasing expression ofγ-GCS. Postgraduate: Zhang Xiu-Feng.(InternalMedicine) Directed by: Prof Dai Ai-Guo...