荷包牡丹碱对哮喘小鼠肺组织α-SMA及气道重构的影响

Investigation of Effect of Bicuculline on Expression of α-smooth Muscle Actin and Airway Remodeling in Asthmatic Mice

目的通过观察鼻内注射γ-氨基丁酸受体(GABAR)特异性拮抗剂荷包牡丹碱对慢性哮喘模型小鼠肺组织α-平滑肌肌动蛋白(alpha-smooth muscle actin,α-SMA)在转录水平及蛋白水平表达及气道重构的影响,探讨拮抗剂在哮喘气道重构中的治疗作用。方法将BALB/c小鼠随机分为正常对照组、哮喘模型组、拮抗剂干预组和激素干预组,用卵蛋白(OVA)致敏激发建立小鼠哮喘模型,采用逆转录聚合酶链反应(RT-PCR)与免疫组化的方法研究肺组织α-SMA的表达及气道形态学参数的改变。结果①与正常对照组比较,在激发哮喘后哮喘模型组肺组织α-SMA的表达升高(P<0.05);与哮喘模型组相比较,各药物干预组α-SMA的表达均降低(P<0.01);拮抗剂干预组和激素干预组比较,小鼠肺组织α-SMA表达无明显差异(P>0.05);②与正常组比较,哮喘模型组支气管基底膜周径(Pbm)、管壁总面积(WAt)、内壁面积(WAi)及平滑肌面积(WAm)均增高(P<0.05);与哮喘模型组比较,激素干预组气道形态学参数均下降(P<0.01),拮抗剂组气道平滑肌面积和管壁总面积下降(P<0.05),各药物干预组比较无明显差异(P>0.05)。结论哮喘小鼠肺组织α-SMA过量表达与哮喘发生密切相关,荷包牡丹碱可以抑制慢性哮喘模型小鼠α-SMA的表达及气道形态结构改变,作用与吸入性皮质激素相似。提示GABAR通过上调α-SMA表达,促进气道平滑肌收缩及增生,参与气道重构的调节。

Objective To observe the effect of bicuculline,which is a selective GABA receptor antagonist on expression of α-SMA in the lung tissue of rats with chronic asthma,to explore the role of the bicuculline on the airway remodeling in asthmatic mice.Methods Forty BALB/c mice were randomly divided into four groups: the control group(A),the asthma model group(B),the bicuculline group(C) and bicuculline with budesonide group(D).The asthmatic model was established by sensitization and challenge with ovalbumin.The expression of α-SMA in the lung tissue and the thickness of the airways of mice was detected by semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR) and immunohistochemical staining.Results There was little expression of α-SMA in the lung tissue of normal mice compared with the asthma model group(P0.05) was observed between group C and D.The WAt/Pbm,WAi/ Pbm,and WAm/ Pbm were significantly increased in the asthma group compared with that in normal group(P<0.05),and the WAt/ Pbm,WAi/ Pbm,and WAm/ Pbm were decrased in the group compared with that of group B(P<0.01),the wAm/Pbm was decreased in the group C(P<0.05).Conclusion Over expression of α-SMA in asthmatic lung tissue is closely related to the onset of asthmatic.GABAAR antagonist bicuculline could inhibit the expression of α-SMA and α-SMA mRNA and alleviate airway remodeling with equivalent potency of inhaled corticosteroid.Our data suggest that GABAAR involve in the pathogenesis of asthmatic airway remodeling by upregulating the expression of α-SMA inducing the airway smooth muscle constriction and hyperplasia.