Fig. 2

Western blotting and densitometric analysis of MMP-1, − 3, and − 13 release in the secretome of chondrocytes following cytokine treatment (IL-1β + TNF-α, both 10 ng/mL) versus control conditions. a Similar MMP-1 release between cytokine-treated chondrocytes vs. control, with the exception of the super-active form of MMP1 (lowest band, indicated by red arrowhead). b Increase in MMP-3 release upon cytokine exposure. c Increase in MMP-13 release upon cytokine exposure. d Beta-actin was measured on western blots of total protein lysates extracted separately from the same samples as a–c as loading control in order to correct for cell number, as no reliable housekeeping protein is available for secreted proteins. Measurements from three horses (three biological replicates) were combined to provide final values for each group (mean ± SD)