[Effects of leptin on airway inflammation and the expression of Th1/Th2 cytokines in asthmatic rats].
OBJECTIVE
To investigate the effects of leptin 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 neutrophils (N) in bronchoalveolar lavage fluid (BALF) were counted. The concentrations of interleukin-4 (IL-4), interferon-gamma (IFN-gamma) 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 H2Oxml(-1)xs(-1), (1.024 +/- 0.096) cm H2Oxml(-1)xs(-1), (1.129 +/- 0.107) cm H2Oxml(-1)xs(-1), (0.946 +/- 0.104) cm H2Oxml(-1)xs(-1), (1.124 +/- 0.095) cm H2Oxml(-1)xs(-1), (1.135 +/- 0.105) cm H2Oxml(-1)xs(-1), respectively.] was increased significantly compared to group B [(0.638 +/- 0.128) cm H2Oxml(-1)xs(-1), (0.745 +/- 0.073) cm H2Oxml(-1)xs(-1), (0.773 +/- 0.090) cm H2Oxml(-1)xs(-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) x 10(4)/ml, (108 +/- 21) x 10(4)/ml, (12.4 +/- 4.0) x 10(4)/ml, (14.2 +/- 5.9) x 10(4)/ml, respectively.] were increased significantly compared to group B [(79 +/- 7) x 10(4)/ml, (2.4 +/- 1.1) x 10(4)/ml] (q = 2.923, 7.063, 8.629, 10.182, all P < 0.05). The concentrations of IFN-gamma 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).


CONCLUSIONS
Leptin could aggravate airway inflammation featured by infiltration of neutrophils and enhancement of Th1 type inflammation.
Cao
Juan
J
Department of Pediatrics, Wuxi People's Hospital Affiliated to Nanjing Medical University, Wuxi 214023, China.
Chen
Jian-Hui
JH
Zhu
Shu-Yang
SY
D000818:Animals; D001249:Asthma / Q000188:drug therapy / Q000276:immunology / Q000378:metabolism*; D005260:Female; D007371:Interferon-gamma / Q000097:blood / Q000378:metabolism*; D015847:Interleukin-4 / Q000097:blood / Q000378:metabolism*; D020738:Leptin / Q000097:blood / Q000494:pharmacology*; D009504:Neutrophils / Q000276:immunology; D051381:Rats; D017207:Rats, Sprague-Dawley
D020738:Leptin; D015847:Interleukin-4; D007371:Interferon-gamma