Evaluating IL-1β's Impact on Chondrocyte Volume

To evaluate the effect of IL-1β on chondrocyte volume, cartilage explants cultured in the regular medium and IL-1β-Supplemented Medium (n = 4 explants from 2 animals per group) were dyed with red fluorescent cell tracker (Red CMTPX Dye, Thermo Fisher) and imaged on a confocal microscope (Zeiss 510) after 4-day culture. The fluorescent image stacks were reconstructed into a 3D image in Image J^{49 (link)}. The volume of in situ chondrocytes was registered and quantified (n ≈ 30 cells from each explant). To estimate the cell proliferation rate, primary chondrocytes were extracted from cartilage explants (n = 4 explants from 2 animals per group). MTT assay was then performed following the previous instructions^{50 (link)}.