Fig. 6: EPA emulsion-integrated HA injection ameliorates ACLT-induced OA progression and decreases CD44 expression in mice.

a A schematic illustration showing the timeline for experiments in ACLT-induced OA mice. Animals were euthanized at either the 4th or 8th week after surgery, and knee joints were subsequently collected for histological and immunohistochemical analyses, respectively. b–h Representative images (b) and quantification (c–h) of H&E staining for each treatment group. The tidemark and subchondral bone line are demarcated with dotted white lines in the magnified histological images: representative images and quantification of Safranin O/Fast Green staining for each treatment group (b and e); representative images of micro-CT scans and quantification of BV/TV and Tb.Pf for each treatment group (b, f and g); and representative images and quantification of immunohistochemical staining of CD44 for each treatment group (b and h). Scale bars (b), 200 μm in original images amd 50 μm in magnified images. i, A schematic illustration summarizing the mechanism through which EPA inhibits the inflammation-induced increase in chondrocyte mechanics by suppressing the NF-κB p65/CD44 signaling pathway and alleviates OA. Data are presented as mean ± s.d. n = 6. Statistical analysis was performed using one-way ANOVA with Tukey’s multiple-comparisons test. *P < 0.05, **P < 0.01, ***P < 0.001.