Eight primary cultures of NPFs were established from nasal polyps from 8 patients, respectively, as previously described.3,4,16 In brief, after removing the epithelial layer, the specimens were immersed overnight in Dulbecco modified Eagle medium (calcium chloride, 265 μg/mL; iron nitrate, 0.1 μg/mL; potassium chloride, 400 μg/mL; magnesium sulfate, 200 μg/mL; sodium chloride, 6400 μg/mL; sodium bicarbonate, 700 μg/mL; sodium phosphate,125 μg/mL; phenol red, 15 μg/mL;HEPES [N-2-hydroxyethylpiperazine-N-2-ethanesulfonic acid] buffer [pH 7.4], 25 mmol/L, and D-glucose, 1 mg/mL) containing 10% fetal calf serum and antibiotics (penicillin, 100 U/mL; streptomycin, 100 μg/mL; and amphotericin B, 0.5 μg/mL). The samples were minced into 1-mm3 fragments and covered with sterilized glass coverslips. After the fibroblasts migrated from tissue explants and became confluent, the cells were trypsinized and subcultured. Cells between passages 3 to 6 were plated at a density of 5 × 105/mL on 10-cm dishes and subjected to various stimulants. Before different treatments, the cells were made quiescent in serum-free media (media without fetal calf serum) for 24 hours.3,4,16 Data given herein are the means of 8 experiments.