2.5 Histological evaluation
Samples of nasal polyps were obtained from each participant during
surgery, and which were treated with fixation and embedded in paraffin.
Then, all of samples were sliced up sections and stained with
hematoxylin and eosin, which were evaluated by two independent observers
under the light microscope (Leica DM4B, Wetzlar, Germany). Five fields
with densest inflammatory cells infiltration in the subepithelial layer
were chosen at 100×magnificantion in each sample. Afterwards the whole
inflammatory cells and eosinophils were observed at 400×magnificantion
(high power field, HPF), and counted in the focal area. The amount of
eosinophils and whole inflammatory cells were recorded in every focal
area under HPF, and the proportion of eosinophils accounted for the
whole inflammatory cells was calculated.