Influence of cytokines/chemokine on mRNA and protein expression of MMPs/TIMPs in hMSCs. hMSCs were incubated with TGF-β1 (100 ng/mL), IL-1β (50 ng/mL), TNF-α (50 ng/mL), SDF-1α (100 ng/mL), or left untreated (control, Con) and cultivated under serum-free conditions for up to 72 hours. (A) mRNA expression of MMP-2, MMP-9, MT1-MMP (MT1), TIMP-1, and TIMP-2 were quantified by qRT-PCR after 24 and 72 hours of incubation with cytokines/chemokine. Results are given as the percentage of change in mRNA expression relative to untreated cells set as 100%. Values represent the mean ± SD of 1 triplicate experiment from 2 independent measurements. (B-C) Aliquots of 72-hour culture supernatants were subjected to zymography. Medium samples were applied in a 1:4 dilution to allow densitometric quantification of proMMP-2 (B) or undiluted to achieve higher sensitivity in the detection of (pro)MMP-9 (C). (D) MT1-MMP protein was determined in cell lysates of hMSCs incubated for 72 hours with and without cytokines/chemokine using the MMP-14 Biotrak Activity Assay. Data are shown as mean ± SD of 1 of 2 triplicate experiments performed. ***P < .001.