RESUMO
OBJECTIVE@#To study the effects of dexamethasone and histamine on the expression of MUC5AC mRNA and protein in human nasal polyps.@*METHOD@#All samples were randomly divided into control group, histamine stimulating group and dexamethasone group. The expression of MUC5AC mRNA and MUC5AC protein in nasal polyps were respectively detected by the methods of reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical assay.@*RESULT@#The expression of MUC5AC mRNA (0.6389 +/- 0.0526) and protein (0.1934 +/- 0.0137) in histamine stimulating group were significantly higher than those of control group (0.3495 +/- 0.0357 and 0.1172 +/- 0.0173, respectively) and reduced (0.4988 +/- 0.0603 and 0.1444 +/- 0.0075, respectively) after treatment with dexamethasone.@*CONCLUSION@#Histamine upregulates MUC5AC mRNA and protein expression. Dexamethasone downregulates MUC5AC mRNA and protein expression, which may be one of the mechanisms of downregulating mucus overproduction by dexamethasone in nasal polyps.