Fig. 4: EPA ameliorates cartilage degeneration and decreases the expression of CD44 and p-p65 in IL-1α-treated porcine osteochondral explants and in human OA cartilage explants.

a A schematic illustration summarizing the experimental design for porcine osteochondral explants. Osteochondral explants were collected from porcine metacarpophalangeal joints using a biopsy punch. b Accumulated loss of sGAG content from porcine osteochondral explants during 10 days of IL-1α treatment. c Mechanical properties of porcine osteochondral explants after 8-day IL-1α treatment. d–f, Representative images (d) and quantification (e and f) of H&E staining (top) and Safranin O/Fast Green staining (bottom) in porcine osteochondral explants under different treatment conditions. g–i Representative images of immunohistochemical staining (g) of CD44 and p-p65 in porcine osteochondral explants under different treatment conditions, and quantification (h and i) of CD44- and p-p65-positive chondrocytes as a proportion of total chondrocytes. j–l, Representative images of immunohistochemical staining (j) of CD44 and p-p65 in human OA cartilage explants treated with or without EPA, and quantification (k and l) of CD44- and p-p65-positive chondrocytes as a proportion of total chondrocytes. Scale bars, 200 μm (d, g and j). Data are presented as mean ± s.d. n = 3 (b), 75 (c) and 6 (e, f, h, i, k and l). Statistical analysis was performed using one-way ANOVA with Tukey’s multiple-comparisons test in b, c, e, f, h and i, or unpaired Student’s t-test in k and l. *P < 0.05, **P < 0.01, ***P < 0.001.