Fig 2: MMP13 enhances corneal wound closure. (A) The qPCR analysis of Mmp13 in unwounded and wounded cornea at d1 post-injury. (B) Representative immunofluorescence staining of MMP13 and KRT6 in unwounded and wounded cornea at d1 post-injury. Scale bar, 100 µm. (C) Western blot analysis of MMP13 proteins in unwounded cornea and wounded cornea treated with or without IFNβ antibody. Representative immunoblots are presented, n = 3. (D) Representative images of the epithelial defect in wounded corneas of control, MMP13 antibody, IFNβ antibody and IFNβ antibody combined with recombinant MMP13 treatment (for each treatment: upper panel, white light micrograph; lower panel, fluorescein staining of corneal surface). (E) Quantification of re-epithelialization in control, MMP13 antibody, IFNβ antibody, and IFNβ antibody combined with recombinant MMP13 treated mice corneas. Epithelial defect is presented as the percentage of the original wound size (Students t-test, n = 5). Data are represented as mean ± SE (*P < 0.05, **P < 0.01, ***P < 0.001).

Fig 3: The cartilage extracts by enzyme degradation method from WO group and T+O group were tested for 4 active proteases.Cartilage explants from WO group and T+O group at day 7, 14 and 21 were extracted by using mean of enzymes as previously described [15]. (A) active ADAMTS-4 was accumulated in the WO group. However, stimulation of T+O significantly induced the elevated level of active ADAMTS-4 retained in the matrix. None of (B) active ADAMTS-5, (C) active MMP-13, (D) active MMP-9 was detected in untreated group or treated group. All values were shown as mean±95% confidence intervals (n = 4 in each group). Error bars indicated the upper limit of 95% confidence intervals.

Fig 4: Profiling of active aggrecanases, MMPs and their specific aggrecan degradation fragments into bovine explants upon T+O stimulation.The releases of (A)active ADAMTS-4.: (D) active MMP-13, (E) active MMP-9, (F)AGNxII and (G)CTX-II started since day 14 and increased over time, while (B) active ADAMTS-5 was unable to be detected during the 21 days. (C) Aggrecanase-mediated aggrecan fragment’s levels peaked at day 7, afterwards, declined to background levels at day 21. No any release of any biomarkers was seen in the WO group. All values were shown as mean ±95% confidence intervals (n = 8 in each group). Error bars indicated the upper limit of 95% confidence intervals.

Fig 5: The effect of broad-spectrum inhibitors on the profiling of active MMPs and their specific aggrecan and collagen degradation fragments.(A) active MMP-13. (B) active MMP-9. (C) AGNxI. (D) CTX-II. All values were shown as mean±95% confidence intervals (n = 8 in each group). Error bars indicated the upper limit of 95% confidence intervals.