Fig. 6.

Modified Pineda and Mankin histology scoring of cartilage repair and OA in murine model after intra-articular injection with PODS® crystals. Safranin-O staining of histological sections from injured joints of 8-week old C57BL/6 mice were assessed for cartilage repair and OA using the Modified Pineda and Mankin scoring systems. A longitudinal, full-thickness cartilage defect was created in the mice with a 27G needle, after which mice were intra-articularly injected with the treatment (all n ​= ​5 per group). Mice sacrificed at Week 4 post-surgery were treated with PODS-bone morphogenic protein-2 (pBMP-2), pBMP-7, or pEmpty in PBS or 0.5% hydrogel, or 0.5% hydrogel alone. Mice sacrificed at eight weeks post-surgery were treated with pBMP-2, pBMP-7 or pEmpty in 0.5% hydrogel. 6.75 ​× ​10 [5] PODS crystals were administered per treatment group, equivalent to 18.75 ​ng of protein. Joints were fixed, sectioned and stained with Safranin O for histological analysis of cartilage repair at 4 and 8 weeks. Sections were scored by two observers blinded to the group assignment to assess the level of cartilage repair and osteoarthritis. Bars show the mean score with error bars representing the conventional error. ∗∗ indicates significant (p ​< ​0.05) improvement in histological score compared with Week 4 pooled data.