卡介菌多糖核酸和地塞米松对哮喘大鼠IFN-γ/IL-4mRNA表达的对比研究  

A comparative study of the effects of BCG-polysaccharide-nucleic acid(BCG-PSN) and dexamesone on the expressions of IL-4 and IFN-γ mRNA

作　　者：汪俊[1] 张伟[2] 

机构地区：[1]中南大学湘雅医院呼吸内科,长沙410008 [2]江西医学院第一附属医院呼吸内科,南昌330006

出　　处：《现代免疫学》2005年第5期406-410,共5页Current Immunology

摘　　要：从分子水平探讨卡介菌多糖核酸(BCG-PSN)对哮喘大鼠Th1、Th2型细胞因子IFN-γmRNA和IL-4mRNA表达的影响以探讨BCG-PSN治疗哮喘的可能机制,并与地塞米松的作用相对比。SD雄性大鼠32只,随机分成盐水对照组、BCG-PSN组、地塞米松和哮喘组四组,每组8只。BCG-PSN组、地塞米松和哮喘组第1、7、14天均用10%鸡卵清蛋白(OVA)1ml联合10%氢氧化铝[AL(OH)3]1ml腹腔注射,第15天起分别以BCG-PSN、地塞米松、生理盐水腹腔注射治疗哮喘,每次治疗后30min以10%OVA雾化吸入激发哮喘,持续30min,持续7d,盐水对照组则以生理盐水腹腔注射和雾化,四组最后一次雾化吸入后24h,以1%戊巴比妥钠麻醉大鼠,收集右上肺组织100mg,采用逆转录-聚合酶链式反应(RT-PCR)半定量测定卡介菌多糖核酸和地塞米松对哮喘大鼠肺组织中IFN-γmRNA、IL-4mRNA表达的影响。结果:BCG-PSN组哮喘大鼠肺组织中IFN-γmRNA表达明显增加,高于正常组、地塞米松组和哮喘组(P<0.05、0.05、0.01,IL-4mRNA表达低于哮喘组和正常组。地塞米松组IL-4mRNA表达低于正常组和哮喘组,IFN-γmRNA表达低于BCG-PSN组而高于哮喘组。哮喘组IL-4mRNA明显高于正常组、BCG-PSN组、地塞米松组。IFN-γmRNA明显低于其余三组(P<0.05)。卡介菌多糖核酸能明显增强哮喘大鼠肺组织中Th1类细胞因子IFN-γmRNA的表达,同时抑制Th2类细胞因子IL-4mRNA的表达,通过双向调节作用提高IFN-γ/IL-4的比值从而逆转Th1/Th2失衡。地塞米松能明显抑制Th2类细胞因子IL-4mRNA的表达,而对Th1类细胞因子IFN-γmRNA的表达无明显改变。The effects of BCG-polysaccharide-nucleie acid （BCG-PSN） and dexamesone on the expression of IL-4 and IFN-γ mRNA were investigated in the molecular level to explore the possible mechanism for their therapeutic action on asthma in rats, in which 32 SD rats were used for study and were randomly divided into saline control group, BCG-PSN group dexamesone group and asthma group, 8 rats in each groups, and the rat model of asthmatic inflammation was induced by sensitization with 10% ovalbumin （OVA） and alum AL（OH）3, each with 1ml, intrapefitoneally injected in 1, 7, and 14 days respectively. Two weeks after the establishment of rat asthmatic model. BCG-PSN（5 mg/kg per day）, dexamesone （5 mg/kg per day） and saline were adnfinistered intraperitoneally for 7 collsecutive days into the BCG-PSN and dexamethone-treated groups and the saline control group of 32 SD rats, respectively, while the saline control group of rats was received with saline injection and saline aerosol 24 hours later after the last provocation. Thereafter. brochioalveolar lavage fluids （BALF） and the lung tissues were to be taken from rats under anaesthesia. The total RNA was extracted from lung tissues, and. the expressions of IL-4 and IFN-γ mRNA were determined by reverse transcriptase-polymerase chain reaction （RT-PCR） using primers for IL-4, IFN-γ and β-actin. Experimental results showed that in the BCG-PSN treated group of rats. the allergic symptoms and the inflammatory infiltration in the musosa of bronchus and lung were hardly observed, and most importantly, it was found that the expression of IFN-γ mRNA was significantly increased with a decreased expression of the IL-4 mRNA, as demonstrated by RT-PCR. In the dexamesone treated group of rats, the allergic symptom were not so obvious, and the inflammatoiy infiltrations both in BALF and lung tissues were rarely observed. However, the expression of IL-4 mRNA in this group was significantly decreased in comparison with those of the asthma and the saline control gro

关 键 词：卡介菌多糖核酸 地塞米松 支气管哮喘 IL-4 MRNA IFN-Γ MRNA RT-PCR 

分 类 号：R392[医药卫生—免疫学]