中文摘要：

目的探讨细胞外信号调节蛋白激酶（ERK）通道调控支气管哮喘大鼠气道平滑肌细胞（ASMC）增殖中的细胞周期机制。方法30只Wistar大鼠随机分为正常组和哮喘组，哮喘组采用卵清蛋白致敏和激发建立哮喘模型。取两组大鼠叶支气管ASMC进行原代培养，采用ERK激动剂表皮生长因子（EGF）和抑制剂PD98059干预哮喘组ASMC。用免疫组织化学法检测ASMC细胞周期蛋白CyclinD1和CDK2的表达；Western免疫印迹检测ERK1／2和磷酸化ERK1／2蛋白的表达，计算ERK活化率。结果哮喘组大鼠ASMC中CyclinD1、CDK2的表达和ERK活化率[76．15±4．88、92．30±7．95和（82．37±5．78）％]均较正常组[54．17±6．11、61．04±4．09和（49．91±3．26）％]显著升高（P均〈0．05）。经EGF处理后上述指标进一步升高[119．28±8．14、134．77±9．26和（91．57±5．32）％，P均〈0．05]，经PD98059处理后显著降低[58．78±4．60、69．15±5．83和（54．01±4．12）％，P均〈0．05]。结论哮喘大鼠ASMC增殖活性增强。ERK1／2可通过诱导ASMC中CyclinD1和CDK2蛋白高表达，使细胞从G1期向S期发展，促进细胞增殖。

英文摘要：

Objective To investigate the effects of extracellular signal regulated kinase （ERK） signaling pathway on cell cycle of airway smooth muscle cells （ASMCs） in asthmatic rats. Methods Thirty Wistar rats were randomly assigned to a control group and an asthma group（ 15 rats in each group）. Asthma model was established by ovalbumim sensitization and challenge. ASMC were isolated and cultured in vitro. The ASMCs from the asthmatic rats were treated with ERK activator epidermal growth factor （EGF） and inhibitor PD98059, respectively. The expressions of cyclin D1 and CDK2 in ASMCs were detected by immunocytochemical staining. The expressions of ERK1/2 and p-ERK1/2 protein were observed by westem blotting for measurement of ERK activation rate. Results Compared with the control group [ 54. 17 ± 6. 11, 61.04 ±4.09, （49. 91 ± 3.26）%, respectively], the expressions of cyclin D1 protein and CDK2 protein, and the rate of ERK activation of ASMCs from the asthmatic rats significantly increased [ 76. 15 ± 4. 88, 92. 30 ± 7.95, （ 82. 37 ± 5.78 ） %, respectively ] （ P 〈 0.05 ）. Furthermore, compared with those before treatment, the expression of cyclin D1 and CDK2, and the rate of ERK activation of ASMCs significantly decreased after treatment with PD98059 [ 58.78 ± 4. 60, 69. 15 ± 5.83, （ 54.01 ± 4. 12 ） %, respectively ] （ P 〈 0. 05 ）, and significantly increased after treatment with EGF [ 119. 28 ± 8. 14,134. 77 ± 9. 26, （ 91.57 ± 5. 32） %, respectively ] （ P 〈 0. 05 ）. Conclusion ERK1/2 participates in proliferation regulation of ASMCs in asthma by enhancing the expressions of cyclin D1 and CDK2, which promotes quiescent cells into S phase.