2.9 | Immunofluorescent staining
The HNECs were seeded in 6-well plates to perform immunofluorescent staining of the TJ of CRSwNP, CRSsNP, and control. When the degree of cell fusion was 100%, the cells were fixed with 4% paraformaldehyde for 15 min, and incubated overnight with ZO-1 antibody at 4 °C. On the next day, the specimens were washed with PBS, and incubated with secondary antibodies in the dark at room temperature for 1 h. After rinsing with PBS, the specimens were incubated with DAPI at room temperature for 10 min. The slices were sealed using nail polish, and the specimens were visualised under a fluorescence microscope (Olympus, Japan).