Fig. 7

Therapeutic efficacy of IA injection of human adipose-derived mesenchymal; stem cells (haMSCs) in the OA model. a In the normal group, HE staining showed natural histology of joints with a thick layer of cartilage and subchondral bone, and chondrocytes in organized lacuna (top panel, 4×, and lower panel, 20×). In contrast, the thickness of the cartilage and especially the subchondral bone in the surgery-induced groups were significantly reduced, and chondrocytes appeared to be more disorganized. haMSC treatment restored the thickness of the cartilage and subchondral bone (scale bar = 500 μm). Note that the meniscus in the surgery groups all displayed damage, confirming the successful surgery of meniscectomy for the model creation. b Safranin-O/Fast green staining for proteoglycan (PG)/collagen content revealed the significant loss of PG (red staining) and increase of fibrillated collagen (green staining), a characteristic of degenerative OA phenotypes in the DiD control group compared with the normal group. Treatment with the DiD-haMSCs exhibited increased proteoglycan expression and decreased type I collagen expression (scale bar = 500 μm), thus restoring the overall cartilage thickness. c Cartilage thickness measured by ImageJ software increased significantly in the haMSC-treatment group compared with the DiD group. d The modified O’Driscoll histological score for morphology and structure characteristics quantified the changes, and supported that haMSC treatment showed significant morphological and structural improvement of cartilage. The P values were obtained using one-way ANOVA analysis of variance (**P < 0.01). All the experiments were repeated at least two times (n = 3)