1. Interleukin-1 is not involved in synovial inflammation and cartilage destruction in collagenase-induced osteoarthritis 
S.C.M. van Dalen, A.B. Blom, A.W. Slöetjes, M.M.A. Helsen, J. Roth, T. Vogl, F.A.J. van de Loo, M.I. Koenders, P.M. van der Kraan, W.B. van den Berg, M.H.J. van den Bosch, P.L.E.M. van Lent 
Osteoarthritis and Cartilage 
Volume 25, Issue 3, Pages (March 2017)
DOI: /j.joca
Copyright © 2016 Osteoarthritis Research Society International Terms and Conditions

2. Fig. 1
Synovial expression of IL-1β is strongly up-regulated in early OA. Synovial gene expression levels of IL-1 related genes and several inflammatory mediators on day 7, 21 and 42 after induction of CiOA in WT mice as determined by qRT-PCR. IL-1β was significantly up-regulated on day 7 after induction of CiOA but decreased thereafter, whereas IL-1α was not regulated. S100A8 and S100A9 gene expression peaked on day 21 after induction of CiOA but returned to basal levels at day 42. Control samples were collected from contralateral joints. Symbols represent individual mice (n = 4 mice per group). Gene expression levels are presented as −ΔCt compared to GAPDH. Open circles represent saline-injected control knee joints, closed circles represent CiOA knee joints. Bars show mean values ± 95% confidence intervals. * = P < 0.05; ** = P < 0.01; *** = P < 0.001.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2016 Osteoarthritis Research Society International Terms and Conditions

3. Fig. 2
Synovial thickening in CiOA is not affected by IL-1. A. Synovial inflammation appeared comparable between WT and IL-1αβ−/− mice, as determined by H&E staining of total knee joints, 7 days after induction of CiOA. Images shown are representative for the treatment groups (original magnification ×50). F = femur, P = patella, S = synovium. B. Synovial inflammation was arbitrarily scored as thickening of the synovial tissue (scale of 0–3). As expected, a strong increase in synovial thickness was found in CiOA knee joints when compared to saline-injected contralateral joints. Surprisingly, synovial thickening in IL-1αβ−/− mice was not different from WT controls on day 7. Symbols represent individual mice (n = 6 mice per group). Bars show mean values ± 95% confidence intervals. *** = P < 0.001.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2016 Osteoarthritis Research Society International Terms and Conditions

4. Fig. 3
IL-1α and IL-1β do not influence synovial mRNA and protein levels of inflammatory mediators. A. Synovial gene expression levels of IL-1 related genes and several inflammatory mediators on day 7 after induction of CiOA in WT and IL-1αβ−/− mice as determined by qRT-PCR. A significant increase in gene expression was observed for all measured genes when CiOA knee joints were compared with control joints, but no differences were found between WT and IL-1αβ−/− mice. Only IL-6 mRNA showed a reduced up-regulation in the CiOA knee joint of IL-1αβ−/− mice. Open circles represent saline-injected control knee joints, closed circles represent CiOA knee joints. B. No differences were measured in systemic protein levels of several inflammatory mediators in the serum of WT and IL-1αβ−/− mice on day 7 after induction of CiOA. S100A8/A9 levels are represented by the right y-axis. Open circles represent WT mice, closed circles represent IL-1αβ−/− mice. C. Local protein levels of S100A8/A9 were measured in synovial washouts, 7 days after induction of CiOA. No differences were found between WT and IL-1αβ−/− mice. Open circles represent saline-injected control knee joints, closed circles represent CiOA knee joints. Gene expression levels are shown as −ΔCt compared to GAPDH. Symbols represent individual mice (n = 6 mice per group). Bars show mean values ± 95% confidence intervals. * = P < 0.05; ** = P < 0.01; *** = P <  ND = not detectable.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2016 Osteoarthritis Research Society International Terms and Conditions

5. Fig. 4
MMP and ADAMTS activity is not reduced in IL-1αβ−/− knee joints compared to WT joints. Synovial mRNA levels of MMPs and ADAMTSs showed a significant increase in CiOA knee joints when compared to control joints, but no differences in gene expression were found between both strains. Open circles represent saline-injected control knee joints, closed circles represent CiOA knee joints (A). MMP and ADAMTS activity in early cartilage damage was studied by immunohistochemical analysis of the presence of aggrecan neo-epitopes VDIPEN (B) and NITEGE (C) with specific antibodies on knee joint sections, collected on day 7 after induction of CiOA, but no differences were found between WT and IL-1αβ−/− mice. The average staining in the IL-1αβ−/− knee joints was assessed and corrected for the average staining in the WT knee joints. Images shown are representative for the treatment groups (original magnification ×200). T = tibia, F = femur, M = meniscus. Symbols represent individual mice (n = 6 mice per group). Bars show mean values ± 95% confidence intervals.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2016 Osteoarthritis Research Society International Terms and Conditions

6. Fig. 5
Absence of IL-1 does not alter cartilage degeneration in end stage CiOA. Sections of complete knee joints of WT and IL-1αβ−/− mice were stained with Saf/O and assessed for cartilage damage on day 42 after induction of CiOA using a modified Pritzker score. No differences were found between the WT and IL-1αβ−/− mice, neither on the individual areas of the tibia-femoral joint, nor on the mean scores. Images shown are representative for the treatment groups (original magnification ×100). T = tibia, F = femur, M = meniscus. Symbols represent individual mice (n = 14 mice per group). Bars show mean values ± 95% confidence intervals.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2016 Osteoarthritis Research Society International Terms and Conditions

7. Fig. 6
IL-1RA treatment does not reduce cartilage damage in end stage CiOA. WT mice with CiOA were treated with IL-1RA in saline in osmotic pumps in the peritoneal cavity. Control mice received empty pumps. Sections of complete knee joints were stained with Saf/O and assessed for cartilage damage on day 28 after induction of CiOA using a modified Pritzker score. No altered cartilage destruction was found after treatment with IL-1RA both on the individual areas of the tibia-femoral joint and the mean scores. Images shown are representative for the treatment groups (original magnification ×100). T = tibia, F = femur, M = meniscus. Symbols represent individual mice (n = 9 or 10 mice per group). Bars show mean values ± 95% confidence intervals.
Osteoarthritis and Cartilage  , DOI: ( /j.joca )
Copyright © 2016 Osteoarthritis Research Society International Terms and Conditions