[The relationship between leukemia inhibitory factor and neurokinin receptors in a rat model of asthma].
OBJECTIVE
To study the expression of leukemia inhibitory factor (LIF) and neurokinin receptors (NKR) in the lungs of asthmatic rats, and to evaluate the role of LIF in airway neurogenic inflammation.


METHODS
Twenty-four Wistar rats were randomly divided into a control group (group A, n = 8), an asthma group (group B, n = 8) and a dexamethasone treated group (group C, n = 8). The rat asthmatic model was made by intraperitoneal injection and nebulized aspiration of ovalbumin (OVA) at the concentrations of 10% and 1% respectively. Expression levels of lung LIF, NK-1R and NK-2R were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot two weeks after challenge, and the localization of NK-1R was determined by immunohistochemistry.


RESULTS
After challenge, the expressions of lung LIF mRNA in group A, B and C were 0.240 +/- 0.020, 0.510 +/- 0.130, 0.180 +/- 0.050, and protein levels were 23 110 +/- 8 018, 40 832 +/- 12 964, 16 160 +/- 2 108 respectively. The expressions of lung NK-1R mRNA in group A, B and C were 0.240 +/- 0.020, 1.040 +/- 0.480, 0.170 +/- 0.040, and protein levels were 16 538 +/- 4 342, 32 292 +/- 4 564, 15 018 +/- 1 488 respectively. The mRNA and protein levels of LIF and NK-1R in group B were significantly elevated as compared with group A and C (all P < 0.01). The expressions of lung NK-2R mRNA in group A, B and C were 0.240 +/- 0.040, 0.200 +/- 0.030 and 0.210 +/- 0.040, and no difference was found among three groups (all P > 0.05). In group B, there was a positive correlation between LIF and NK-1R at mRNA (r = 0.850, P < 0.01) and protein (r = 0.868, P < 0.01) levels respectively. NK-1R immunoreactivity was observed primarily in bronchial epithelial cells.


CONCLUSIONS
LIF and NK-1R were excessively expressed and closely correlated in lungs of the rat asthmatic model, suggesting that LIF may be involved in modulating airway neurogenic inflammation.
Lin
Min-juan
MJ
Department of Respiratory Medicine, First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
Lao
Xue-jun
XJ
Ma
Hong-ming
HM
Tang
Yan
Y
D000818:Animals; D001249:Asthma / Q000378:metabolism*; D004195:Disease Models, Animal; D053605:Leukemia Inhibitory Factor / Q000378:metabolism*; D008168:Lung / Q000378:metabolism; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000378:metabolism*; D018041:Receptors, Neurokinin-2 / Q000378:metabolism*
D053605:Leukemia Inhibitory Factor; D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2