GABA和一叶秋碱对哮喘小鼠肺功能和黏液的影响

Effects of GABA and Securinine on the lung function and mucus of asthmatic mice

目的探讨GABA和GABAA受体拮抗剂一叶秋碱(securinine,Se)对于哮喘小鼠肺功能、气道炎症和黏液生成的变化的影响。方法80只Balb/c小鼠随机分为肺功能检测组和黏液组2大组,每大组再分为磷酸盐缓冲液(PBS)对照组、哮喘组(OVA)、OVA/GABA组和OVA/Se组4小组,各10例。以卵白蛋白(OVA)致敏激发制作哮喘小鼠模型,PBS组以PBS替代OVA,药物干预组激发时分别给予GABA或Se。肺功能检测组采用Powerlab系统记录跨肺压、流速、潮气容积的变化,计算出肺阻力(RL)、用力最大呼气流速(PEF)、第0.4s用力呼气容积/用力肺活量(FEV0.4/FVC)。末次激发后24h处死黏液组小鼠,收集各组小鼠支气管肺泡灌洗液(BALF),行嗜酸粒细胞计数,免疫组织化学法(ICH)检测气道黏蛋白Muc5ac蛋白的表达。结果与PBS组比较,OVA组、OVA/GABA组、OVA/Se组,分别以0.5和1.5g/LAch激发时,RL无明显变化;以5.0、15.0和45.0g/LAch激发时,3组的RL均升高,OVA组和OVA/Se组的RL均高于OVA/GABA组(P<0.01);3组的PEF、FEV0.4/FVC均下降,OVA/GABA组高于OVA和OVA/Se组(P<0.01);3组小鼠气道黏膜炎症未见明显差别。OVA+GABA组和OVA组的Muc5ac蛋白的表达强于OVA+Se组(P<0.01),但3组均高于对照组。结论GABA可改善哮喘小鼠呼吸力学指标及增加气道黏液高分泌,而Se可以减少气道黏液高分泌。

【Objectives】To observe the effects of GABA/GABAA receptor inhibitor （securinine） on lung function, airway inflammation and mucus in asthmatic mice. 【Method】Balb/c female mice were divided randomly into 4 groups （n=10）： phosphate buffer solution （PBS） control group, OVA group, OVA/GABA group, OVA/Se group. We used a murine model of asthma induced by sensitized and challenged with ovalbumin. Asthmatic symptoms were observed. The changes in airway responsiveness represented by lung resistance （RL） stimulated by acetylchdine （Ach） and function of lung in terms of peak expiratory flow （PEF） and the ratio of forced expiratory volume in 0.4 second （FEV0.4）/forced vital capacity （FVC） were determined. Lung tissue sections with hematoxylin and eosin （HE） staining for general pathology, alcian blue-periodic acid shift （AB-PAS） staining for identification of goblet eellsmueus secretion in lung tissue were examined. After 24 hours of the last challenged, BALF was collected and the percentage of EOS was counted. Muc5ac protein in airway was detected by immunohistochemical assay. [Result] Compared with those in PBS control group, the total RL was increased, PEF and ratio of FEV0.4/FVC were decreased in other three groups when stimulated by Ach （5.0, 15.0 and 45.0g/L） （respectively P 〈0.01）. Compared with OVMSe and O-VA groups, asthma symptoms were not more severe; the total RL decreased; PEF and ratio of FEV0.4/FVC were increased in OVA/GABA group. The expression of Muc5ac protein in airway of OVA group was more than OVA/Se groups （P 〈0.01）, but less than OVA/GABA group. [ Conclusions] GABA can improve the the OVA-induced airway hyperreactivity, Se can reduce mucus overproduction.