Nasal turbinate sections of 4- to 5-μm thickness were deparaffinized in xylene,
rehydrated in alcohol and incubated in 0.3% H2O2 to block endogeneous peroxidase activity. For immunohistochemistry (IHC), the slides were incubated with rabbit polyclonal antibody against OPN (Zhongshan Goldenbridge, Beijing, China) (1: 200) or rabbit polyclonal antibody against leptin (Thermo Fisher Scientific, Fremont, CA, USA) overnight at 4 °C. At the second day, the samples were then incubated with secondary biotinylated goat anti-mouse/rabbit IgG antibody, followed by avidin-peroxidase complex (Thermo Fisher Scientific, Fremont, CA, USA). After additional washing, the slides were stained with 3% diaminobenzidine chromogen, counter-stained with hematoxylin, and affixed with a coverslip. Isotype-matched IgG was used in place of the primary antibody as the negative control.
rehydrated in alcohol and incubated in 0.3% H2O2 to block endogeneous peroxidase activity. For immunohistochemistry (IHC), the slides were incubated with rabbit polyclonal antibody against OPN (Zhongshan Goldenbridge, Beijing, China) (1: 200) or rabbit polyclonal antibody against leptin (Thermo Fisher Scientific, Fremont, CA, USA) overnight at 4 °C. At the second day, the samples were then incubated with secondary biotinylated goat anti-mouse/rabbit IgG antibody, followed by avidin-peroxidase complex (Thermo Fisher Scientific, Fremont, CA, USA). After additional washing, the slides were stained with 3% diaminobenzidine chromogen, counter-stained with hematoxylin, and affixed with a coverslip. Isotype-matched IgG was used in place of the primary antibody as the negative control.