平喘宁对哮喘大鼠Bcl-2,Bax,EGF mRNA及PDGF mRNA表达的影响

目的:观察平喘宁对寒性哮喘大鼠的肺功能、气道形态学、肺组织中B细胞淋巴瘤/白血病-2(Bcl-2),Bcl-2相关X蛋白(Bax),表皮生长因子(EGF)mRNA及血小板衍生生长因子(PDGF)mRNA表达的影响。方法:将105只雄性SD大鼠随机分为正常组、模型组、桂龙咳喘宁组、地塞米松组、平喘宁高、中、低剂量组,每组15只。以卵蛋白致敏及寒冷刺激复制大鼠寒哮模型,造模21 d后,各给药组分别给予桂龙咳喘宁组(10 g·kg~(-1)·d~(-1)),地塞米松组(0.4 mg·kg~(-1)·d~(-1)),平喘宁高、中、低剂量组(19.6,9.8,4.9 g·kg~(-1)·d~(-1)),ig给药,正常组、模型组每天ig给予等量蒸馏水,连续给药4周,处死前测定肺功能,处死后解剖大鼠并取出肺组织。采用免疫组化法测定肺组织中Bcl-2及Bax的表达。采用苏木素和伊红(HE)染色行病理形态学改变观察,采用逆转录—聚合酶链式反应(RT-PCR)半定量检测EGF mRNA,PDGF mRNA表达丰度。结果:与正常组比较,模型组大鼠支气管炎性细胞浸润明显,显著变窄,平滑肌增厚;肺功能下降(P0.01)。Bcl-2表达升高,Bax表达降低(P0.01);EGF mRNA,PDGF mRNA表达升高(P0.01)。与模型组比较,各给药组的肺组织病理改变减轻;肺功能有不同程度的好转(P0.01,P0.05)。各给药组肺组织中Bcl-2表达降低,Bax表达增加(P0.01,P0.05)。各给药组EGF mRNA,PDGF mRNA表达水平降低(P0.01,P0.05)。结论:平喘宁可降低哮喘大鼠Bcl-2蛋白的表达,升高Bax蛋白的表达;抑制EGF mRNA,PDGF mRNA表达,从而抑制细胞外信号调节蛋白激酶(ERK)通路活化,减轻炎性反应,改善肺功能,抑制气道平滑肌增生,延缓气道重塑而治疗哮喘。

Effect of Pingchuanning on Expression of Bcl-2, Bax, EGF mRNA, PDGF mRNA in Lung Tissues of Asthma Rats

Objective: To investigate the effect of Pingchuanning on B-cell lymphoma/leukemia-2(Bcl-2), Bcl-2 associated X protein(Bax), epidermal growth factor(EGF) mRNA, platelet-derived growth factor(PDGF) mRNA expressions, lung function and airway morphology in cold asthma model rats. Method: One hundred and five SD male rats were randomly divided into normal group, model group, Guilong Kechuanning group, dexamethasone group, Pingchuanning high-dose group, medium-dose group and low-dose group with 15 in each group. The ovalbumin sensitization and cold stimulation were adopted to establish the rat asthma model. At the 21st day after the modeling, normal and model groups were given the same amount of distilled water every day, the dexamethasone group(0.4 mg·kg^-1·d^-1), Guilong Kechuanning group(10 g·kg^-1·d^-1) and Pingchuanning high, medium and low dose groups(19.6,9.8,4.9 g·kg^-1·d^-1) were given corresponding drugs for four weeks. And the changes in lung function of asthma rats were observed, then Bcl-2 and Bax protein expressions of the lung tissues were detected by immunohistochemical assay. The lung histopathological changes were observed by hematoxylin and eosin(HE) staining. Expression of EGF mRNA and PDGF mRNA in the lungs were detected by RT-PCR. Result: Compared with the normal group, the model group showed obvious inflammatory cells invasion, stricture of bronchus, thickening of airway smooth muscle and declined lung function(P<0.01);increases in Bcl-2 protein, EGF mRNA, PDGF mRNA(P<0.01);and decrease in Bax expression(P<0.01). Compared with the model group, all treatment groups showed improvements in the lung function and pathological changes to varying degrees(P<0.01,P<0.05);decreases in Bcl-2 protein, EGF mRNA, PDGF mRNA(P<0.01,P<0.05);and increase in Bax expression(P<0.01,P<0.05). Conclusion: Pingchuanning could reduce the expression of Bcl-2 protein and improve Bax protein in lung of asthmatic rats, inhibit the activation of ERK pathway, alleviate inflammatory reaction, improve the lung function, reduce airway smooth muscle hyperplasia, delay the airway remodeling and treat asthma, by the inhibition of EGF mRNA and PDGF mRNA.