摘要
目的探讨褪黑素(MT)对哮喘大鼠CD4+CD25+调节性T细胞(CD4+CD25+Tr)的影响及抗感染作用。方法SPF级SD大鼠32只随机分成4组,每组8只。哮喘组:造模第1、7天,大鼠腹腔注射卵清蛋白(OVA)和氢氧化铝混悬液体,第14天,用10g/L的OVA溶液对大鼠进行雾化激发,1次/d,20min/次,连续7d;MT组:致敏、诱导哮喘方法同哮喘组,在每次激发前30min,腹腔注射MT0.1mg/kg;地塞米松组:致敏、诱导哮喘方法同哮喘组,在每次激发前30min,腹腔无菌注射地塞米松0.5mg/kg;对照组:注射、雾化方法同哮喘组,以9g/L盐水替代OVA和氢氧化铝致敏液及雾化液。各组于最后1次雾化激发后取其外周血涂片染色,计数其外周血嗜酸性粒细胞(EOS)百分比;收集其肺泡灌洗液(BALF),计数其炎性细胞总数;制作肺组织石蜡切片,HE染色计数其呼吸道周围EOS数目;用免疫增强浊度法检测其血清IgE水平;用流式细胞术检测其外周血CD4+CD25+Tr水平。采用SPSS10.0软件进行统计学分析。结果哮喘组外周血CD4+CD25+Tr/CD4+T细胞值与呼吸道周围EOS细胞数呈高度负相关(r=-0.73 P<0.05),与BALF细胞总数亦呈高度负相关(r=-0.78 P<0.05),与血清IgE水平未见显著相关。CD4+CD25+Tr/CD4+T细胞值哮喘组显著高于其他各组(Pa<0.01),其他3组比较,差异无统计学意义(Pa>0.05)。MT组呼吸道周围EOS计数、外周血EOS比例、BALF细胞总数及IgE水平显著低于哮喘组(Pa<0.01)。结论CD4+CD25+Tr参与哮喘的发病。MT能显著降低哮喘大鼠CD4+CD25+Tr的数目,对哮喘大鼠CD4+CD25+Tr的调节作用与地塞米松相当,可有效减轻哮喘大鼠呼吸道炎性反应和血清IgE上升水平。
Objective To explore the effect of Melatonin（MT） on CD4^＋CD25^＋regulatory T cell （CD4^＋CD25^＋Tr） and airway inflamma- tion in asthmatic rat. Methods Thirty - two SD rats were randomly divided into 4 groups, 8 rats in each group. Asthmatic group ： rats were im- munized on day 1 and 7 by intraperitoneal inject of mixture of ovalbnmin（OVA） and alnminnmhydroxide. From day 14 ,the animals were allenged with aerosolized OVA for 20 min per day for 7 consecutive days. MT group ： OVA - sensitized rats were injected intraperitoneally with 0. 1 mg/kg MT 30 min before each OVA challenge. Dexamethasone group：OVA -sensitized rats were injected intraperitoneally with 0.5 mg/kg Dexamethasone 30 min before each OVA challenge. Control group：OVA for inhalation and MT for intraperitoneal injection was replaced with saline. After the last challenge, peripheral blood was stained to count the percentage of eosinophil （EOS）. Then the rats were lavaged and total leukocytes counts in bronchoalveolar lavage fluid（BALF） were performed after staining with Wright - Giemsa staining. The EOS counts around the airway was counted after the histological section of lung staining with hematoxylin and eosin staining. The serum level of immnnoglobnlin E （IgE） was detected by irnmunoenhancement. The change of CD4^＋CD25^＋ Tr was assessed with flow cytometry. SPSS 10.0 software was applied to analyze data. Results In asthmatic rats,the CD4^＋CD25^＋ Tr/CD4^＋ T cells ratio had significant negative relationship with the EOS counts around the airway and the total leukocytes counts in BALF （ r = - 0.73 P 〈 0.05 ; r = - 0.78 P 〈 0.05, respectively）. The CD4^＋CD25^＋Tr/CD4^＋ T cells ratio of asthmatic rats increased rapidly compared with control group （Pa 〈 0.01 ）. There were no significant changes between the other three groups（P 〉 0.05 ）. There was a significant decrease in the percentage of the eosinophils in peripheral blood, the eosinophil counts around the airway,the total leukocytes counts in BALF and the serum level of IgE in MT group compared with asthmatic group （Pa〈 0.01 ）. Conclusions CD4^＋CD25^＋ Tr plays an important role in pathogenesis of asthma. MT can effectively control airway inflammation and serum level of IgE through down regulation of CD4^＋CD25^＋ Tr number.
出处
《实用儿科临床杂志》
CAS
CSCD
北大核心
2008年第4期298-300,共3页
Journal of Applied Clinical Pediatrics
基金
宜昌市医疗卫生科技计划项目资助(A2007302-12)
