Immunohistochemistry of Human Articular Cartilage

Human OA articular cartilage of full thickness (n = 3) was processed and sectioned as previously described (Liu et al., 2020 (link)). The sections were treated by 3% hydrogen peroxide in methanol for 30 min, and by 100 mg/mL hyaluronidase for 15 min. After blocking non-specific binding with 3% bovine serum albumin (BSA) in PBS, immunohistochemistry was performed with primary antibodies (mouse anti-CD166 Abcam, MA, United States, catalog number: ab233750), 1:100; rabbit anti-IL-1β (Santa Cruz Biotechnology, TX, United States, catalog number: sc-7884) at 4°C overnight. Sections were stained for 30 min with a red fluorescently labeled anti-mouse secondary antibody and/or a green fluorescently labeled anti-rabbit secondary antibody (Invitrogen, MA, United States). The VECTASHIELD Mounting Medium with DAPI was used for cell nuclear staining and section storage. The section was Images were acquired at 4× and 20× magnification using a Nikon Eclipse 90i Digital Imaging System.