Immunohistochemistry
Lung tissue sections (5 μM) were incubated with TLR2 antibody at 4°C overnight. Second day, the sections were incubated with HRP-conjugated secondary antibody (Beijing Golden Bridge Biotechnology, Beijing, China) for 1 h at 37°C. After rinsed for three times, sections were stained by diaminobenzidine (DAB) and counterstained by hematoxylin, and dark-brown staining was considered positive. The image were obtained under an Carl Zeiss Axio Scope.A1 (Carl Zeiss, German).