Fig. 2.

Constitutive epidermal growth factor receptor (EGFR) overactivation attenuates cartilage damage caused by loading. (A) The study protocol shows that 2-month-old WT and HBEGF Over^Col2 mice were subjected to 6 or 9 N loading at their right tibiae, followed by joint harvest later. H, harvest. (B) Representative safranin-O/Fast green-stained sections of WT and HBEGF Over^Col2 cartilage at 2 weeks, 1 month and 3 months after loading. Two black dashed lines indicate a cartilage lesion site between them. Scale bars, 100 μm. (C) Cartilage injury length was quantified (n = 6/group). (D) OA severity at 3 months after loading was assessed by Mankin score (n = 6/group). (E) Immunostaining of p-EGFR in uninjured articular cartilage from WT and HBEGF Over^Col2 mice. Scale bars, 50 μm. The comparisons were conducted by two-way ANOVA with Tukey–Kramer multiple comparison test.