Expressions of the common β subunit and specific α subunit of IL-5, IL-3, and GM-CSF receptor mRNA in eosinophils in BALF from guinea pigs with asthma / 第三军医大学学报

ABSTRACT

Objective　To investigate the relationship of the expressions of common β (βcR) and specific α chains of IL-5, IL-3 and GM-CSF receptors with the eosinophils（Eos） apoptosis for the roles of these receptors in asthma. Methods　All of 12 guinea pigs were equally randomized into normal and ovalbumin sensitized asthmatic group. The apoptosis of hypodense and normodense Eos in bronchoalveolar lavage fluid (BALF) was detected by TUNEL method. The expression of common β and specific α chains of the 3 receptor mRNA were measured with RT-PCR and in situ hybridization. Results　More Eos were observed in asthmatic group than in normal group, especially those in hypodense (P<0.01). The apoptotic rate of Eos in BALF were significantly lower in asthmatic group than in normal animals (P<0.01), but no difference was found between hypodense and normodense Eos. Compared with normal group, the expressions of the 3 receptor mRNA α chains were decreased in asthmatic group than in normal group (P<0.01), but βcR expression was increased significantly. More IL-3 Rα and GM-CSFRα mRNA were expressed in hypodense Eos than in normodense Eos. The contents of IL-5Rα and IL-3Rα mRNA were lower in asthmatic group than in normal group. Conclusion　The apoptosis of Eos is inhibited in BALF from guinea pigs with asthma. The expressions of IL-5, IL-3 and GM-CSF receptors in Eos are regulated through 2 mechanisms: the reduced expressions of their specific α chains which attenuating the negative regulation on Eos activation and inhibited apoptosis and the increased expressions of their βcR which enhancing the positive regulation on the 2 aspects. These data suggest that IL-5, IL-3 and GM-CSF receptors might be involved in the pathogenesis of asthma through regulating the apoptosis of Eos.