IHC
After rats were euthanized, cartilage was harvested, and the articular
part of the right knee of rats was isolated and then dehydrated,
decalcified, and embedded in paraffin. The knee articular tissue was
placed in EDTA decalcification (Servicebio, Wuhan, China) solution and
shaken at 120 rpm at a constant temperature (25 ℃ ~ 30
℃). Longitudinal-oriented sections (3 µm) of the knee joint were cut
using a paraffin microtome (RM2265, Leica, Germany). The primary
antibodies used were anti-IL-6 (1:500, Sigma-Aldrich) and anti-MMP-13
(1:50, Absin, Shanghai, China). IHC labelling was applied as routine
technology. In brief, after being blocked with 10% goat serum for 20
min at room temperature, sections were incubated with primary antibodies
for 1 h at 37 ℃ . Horseradish peroxidase-labelled secondary antibodies
were added and stood at room temperature for 1 h. The nucleus was then
stained by mounting medium with DAPI and observed with a digital
pathology image scanner (version 12.3.3.5048, Leica, Wetzlar, Germany).