哮喘豚鼠嗜酸性粒细胞神经趋化及气管平滑肌毒蕈碱受体、主要碱性蛋白的异常表达

The chemotaxis of eosinophils to nerve and abnormal expressions of muscarinic receptors and major basic protein in the tracheal smooth muscle in asthmatic guinea pigs

目的:研究哮喘豚鼠气管平滑肌毒蕈碱受体(MR)mRNA及嗜酸性粒细胞主要碱性蛋白(major basic protein,MBP)mRNA的表达及嗜酸性粒细胞(Eos)向迷走神经的趋化作用。方法:20只健康豚鼠随机分为正常组和哮喘组。哮喘组制作成哮喘豚鼠模型,再激发用药。测定支气管肺泡灌洗液(BALF)的细胞总数及细胞分类,观察肺组织的病理改变,乙酰胆碱酯酶及HE染色观察Eos神经趋化情况,进行气管平滑肌的M2R mRNA、M3RmRNA、MBP mRNART-PCR半定量分析。结果:两组BALF的Eos计数,哮喘组[(29.2±7.3)%]与正常组[(2.8±3.0)%]比较差异有显著性(P<0.01)。哮喘组肺组织充血水肿明显,Eos肺组织浸润较正常组明显,Eos具有明显的神经趋化现象。气管平滑肌的MR mRNA、MBP mRNART-PCR半定量分析显示,M2RmRNA,哮喘组(1.26±0.24)与正常组(0.50±0.16)比较差异有显著性(P<0.01);M3R mRNA,哮喘组(0.12±0.055)与正常组(0.42±0.062)比较差异有显著性(P<0.01);MBP mRNA,哮喘组(1.46±0.208)与正常组(0.25±0.089)比较差异有显著性(P<0.01)。结论:哮喘豚鼠Eos具有迷走神经趋化现象,M2R表达增加,M3R表达减少,MBP表达增加。

Objective To investigate the expressions of muscarinic receptors（MR） and major basic protein（MBP） mRNA in the tracheal smooth muscle and chemotaxis of eosinophils to the vague nerve. Methods Twenty healthy guinea pigs were randomized to either control or asthma group. The guinea pig model of asthma was constructed. The total cell count and classification in BALF collected from the guinea pigs were measured, pathologic changes in the lung tissues were detected, state of nervous chemotaxis was observed using AchE with H＆E stain, and M2R, M3R, and MBP mRNA in the tracheal smooth muscle were analyzed semi-quantitively by RT-PCR. Results The eosinophil count in the BALF differed significantly between the two groups [ （29.2 ± 7.3）% vs （2.8 ± 3.0）%, P 〈 0.01 ]. Congestion and edema developed evidently in the lung tissues in the asthma group, so did eosinophil infiltration, exhibiting marked chemotaxis to nerve. RTPCR revealed that the quantities of M2R, M3R, and MBP mRNA differed significantly between the asthma group and the control group （1.26 ± 0.24 vs 0.50 ± 0.16,0.12 ± 0.055 vs 0.42 ± 0.062, and 1.46 ± 0.208 vs 0.25 ± 0.089, respectively; P 〈 0.01 for all comparisons）. Conclusion In the asthmatic guinea pigs, eosinophils possess the chemotaxis to nerve and the expressions of M2R and MBP are increased but M3R expression is declined.