The detection of lnterleukin-5 mRNA expression in nasal polyps by RT-PCR

OBJECTIVE To investigate the Interleukin-5 mRNA expression in nasal polyps. METHODS A reverse transcription- polymerase chain reaction (RT-PCR) was used to semi quantitatively detect the IL-5 mRNA level in eleven nasal polyps and eight control middle turbinates. Total tissue RNA was extracted and was reverse transcripted to first strand cDNA. The primers used in PCR were: 5' primer, 5'-GCTTCTGCATTTGAGTTTGCTAGCT-3'and 3' primer, 5'-TGGCCGTCAATGTATTTCTTTATTAAG-3', which spanned a 294-nucleotide fragment. For semi quantitative analysis of IL-5 mRNA, band intensities of amplification products for IL-5 and β -actin of individual subjects were quantitated with a densitometer, and the density ratio (IL-5/ β -actin) was calculated by dividing the intensity of the band of IL-5 by that of P -actin in the same subject. RESULTS IL-5 mRNA was observed in all eleven nasal polyp specimens, but only one of eight middle turbinates specimens. CONCLUSION The expression of IL-5 mRNA in nasal polyps is higher than in normal tissue. IL-5 mRNA may play a important role in the pathophysiology and pathogenesis of in nasal polyps.