瘦素对支气管哮喘大鼠气道炎症及Th1/Th2细胞因子表达作用的影响

目的 探讨瘦素对支气管哮喘(简称哮喘)大鼠气道炎症和Th1/Th2细胞因子表达的影响.方法 应用随机数字表法将40只雌性SD大鼠随机分为正常体重对照组(A组)、正常体重哮喘组(B组)、正常体重瘦素干预组(C组)、肥胖对照组(D组)和肥胖哮喘组(E组),建立大鼠肥胖和哮喘模型.测定气道反应性,计数BALF中白细胞总数、嗜酸粒细胞及中性粒细胞数目,ELISA法测定血清和BALF中白细胞介素(IL)-4、γ-干扰素(IFN-γ)及瘦素浓度,Western blot及逆转录PCR法测定肺组织瘦素蛋白及mRNA的表达.结果 C、E组大鼠以10、100、300 ug/kg浓度乙酰胆碱尾静脉注射后气道阻力[分别为(0.89±0.11)、(1.02±0.10)、(1.13±0.11)cm H2O·ml-1·s-1(1 cm H2O=0.098 kPa)和(0.95±0.10)、(1.12±0.10)、(1.14±0.10)cm H2O·ml-1·s-1],明显高于B组[分别为(0.64±0.13)、(0.74±0.07)、(0.77±0.09)cm H2O·ml-1·s-1],均P<0.05.C、E组BALF中白细胞总数[分别为(91±9)×104/ml和(108±21)×104/ml],中性粒细胞计数[分别为(12.4±4.0)×104/ml和(14.2±5.9)×104/ml]均高于B组[分别为(79±7)×104/ml和(2.4±1.1)×104/ml],均P<0.05.C、E组血清及BALF中IFN-γ浓度[分别为(42.3±3.5)、(45.1±4.8)、(19.2±1.8)和(20.3±1.5)ng/L]明显高于B组[分别为(16.5±1.4)和(9.3±1.0)ng/L],均P<0.05.C、E组肺组织瘦素蛋白及mRNA表达[分别为(0.40±0.07)、(0.44±0.05)ng/L和(0.34±0.06)、(0.38±0.04)ng/L]均明显高于B组[(0.31±0.03)ng/L和(0.21±0.04)ng/L],均P<0.05.结论 瘦素可促进哮喘气道炎症,并以中性粒细胞浸润和Th1型炎症反应增强为特点.

Effects of leptin on airway inflammation and the expression of Th1/Th2 cytokines in asthmatic rats

Objective To investigate the effects of hptin on airway inflammation and the expression of Th1/Th2 cytokines. Methods The obesity and acute asthma models were established in 40 female SD rats, which were randomly divided into a normal weight control group (group A), a normal weight asthmatic group (group B), a normal weight intervention group (group C), an obese control group (group D) and an obese asthmatic group (group E). The airway resistance and airway responsiveness were calculated by transpulmonary pressure and gas flow rate. The numbers of leukocytes, eosinophils (EOS) and neutrephils (N) in brenchoalveolar lavage fluid (BALF) were counted. The concentrations of interleukin-4 (IL-4), interferon-γ(IFN-γ) and leptin in serum and BALF were determined by ELISA. The protein and Mrna expression of leptin was measured by Western blot and RT-PCR respectively. Results The airway resistance in group C and E [(0.890±0.106)cm H2O·ml-1·s-1 (1.024±0.096)cm H2O·ml-1·s-1(1.129±0.107) cm H2O·ml-1·s-1, (0.946±0.104) cm H2O·ml-1·s-1, (1.124±0.095)cm H2O·ml-1·s-1, (1.135±0.105) cm H2O·ml-1·s-1,respectively.] was increased significantly compared to group B [(0.638±0.128) cm H2O·ml-1·s-1, (0.745±0.073) cm H2O·ml-1·s-1,(0.773±0.090) cm H2O·ml-1·s-1] (q=7.128, 8.712, 8.318, 11.300, 11.258, 11.447, all P<0.05). The numbers of leukocyte and neutrophils in group C and E [(91±9)×104/ml, (108±21)×104/ml, (12.4±4.0)×104/ml, (14.2±5.9)×104/ml, respectively.] were increased significantly compared to group B [(79±7)×104/ml, (2.4±1.1)×104/ml] (q= 2.923, 7.063, 8.629, 10.182,all P<0.05). The concentrations of IFN-γ were [(42.3±3.5) ng/L, (45.1±4.8) ng/L, (19.2±1.8) ng/L, (20.3±1.5)ng/L] in group C and E respectively, which were significantly higher than those of group B[(16.5±1.4) ng/L,(9.3±1.0) ng/L] (q= 21.607, 23.952, 16.919, 18.799, all P<0.05). The protein and Mrna expression of leptin in lung tissue in group C and E[(0.40±0.07)ng/L,(0.44±0.05) ng/L,(0.34±0.06) ng/L,(0.38± 0.04)ng/L, respectively.] were remarkably higher than those of group B [ (0.31±0.03) ng/L, (0.21±0.04) ng/L] (q=4.648, 6.713, 8.222, 10.752, all P<0.05). Conclusion Leptin could aggravate airway inflammation featured by infiltration of neutrophils and enhancement of Th1 type inflammation.