Representative images of peripheral blood (PB)-derived mesenchymal stem cells (MSCs) in their undifferentiated state (A & C) and chondrogenic induced (B & D) after Hematoxylin (A & B) and Crystal Violet (C & D) stainings.

<p>The typical chondrogenic morphology and lacune formation (black arrow) can be noticed after induction. Scale bars represent 50 µm.</p

Clinical evolution scores of the different treatments at different time points in the first study (A).

<p>Values are given as the mean ± SEM. Diagrams represent the clinical evolution scores of 30 horses treated with native mesenchymal stem cells (MSCs) and PRP (Combination 1, n = 15) or chondrogenic induced MSCs and PRP (Combination 2, n = 15) in the second study (<b>B</b>).</p

Immunocytochemistry on adhesive mesenchymal stem cells (MSCs) using Ki67 (A), collagen (Col) type II (B), vimentin (C) and p63 (D).

<p>Native MSCs were negative for p63 and positive for Ki67, Col II and vimentin, whereas chondrogenic induced MSCs were positive for p63, Col II and vimentin with a decreased signal for Ki67 (arrows = negative nuclei). The relevant isotype controls were negative. Scale bar represents 50 µm.</p

Clinical evolution scores with average and standard deviation (STD) at different time points for the different treatment groups: 1 = platelet-rich plasma (PRP), 2 = mesenchymal stem cells (MSCs), 3 = PRP+MSCs, and 4 = PRP+chondrogenic induced MSCs.

<p>Clinical evolution scores with average and standard deviation (STD) at different time points for the different treatment groups: 1 = platelet-rich plasma (PRP), 2 = mesenchymal stem cells (MSCs), 3 = PRP+MSCs, and 4 = PRP+chondrogenic induced MSCs.</p

Clinical evolution scores at 6 weeks after treatment of 15 horses with native mesenchymal stem cells (MSCs) and PRP (Combination 1) or chondrogenic induced MSCs and PRP (Combination 2).

<p>Clinical evolution scores at 6 weeks after treatment of 15 horses with native mesenchymal stem cells (MSCs) and PRP (Combination 1) or chondrogenic induced MSCs and PRP (Combination 2).</p

Flow cytometry confirmed a low expression of major histocompatibility complex (MHC) class I and no expression of MHC class II on the native MSCs and chondrogenic induced MSCs.

<p>The light and dark grey histograms represent the relevant isotype control staining and marker antibody staining, respectively with the corresponding percentage of mean positive cells ± SEM.</p

Median, minimum (min) and maximum (max) of the early and late evolution score are indicated per treatment: platelet-rich plasma (PRP), native mesenchymal stem cells (MSCs), combination (Comb) 1 (native MSCs and PRP) or Comb 2 (chondrogenic induced MSCs and PRP).

<p>The “early” score indicates the average of the clinical evolution scores at 6 weeks and 12 weeks, whereas “late” indicates the average of the clinical evolution scores at 6 months and 12 months after treatment.</p

Representative images of peripheral blood (PB)-derived mesenchymal stem cells (MSCs) in their undifferentiated state (A & C) and chondrogenic induced (B & D) after Alcian Blue (A & B) and Safranin O (C & D) stainings.

<p>Glycosaminoglycan production (black arrows) can be noticed after induction. Scale bars represent 50 µm.</p

All the patients were clinically assessed for joint effusion, response to flexion test and lameness according to the American Association of Equine Practitioners (AAEP).

<p>Because the importance of each parameter was correlated with its impact, the sum of these 3 parameters was reckoned as the overall clinical severity score (0 to 10).</p

Results of RT-PCR for the gene expression of collagen (Col) type II, aggrecan and cartilage oligomeric matrix protein (COMP) in the native MSCs (Ctrl) and chondrogenic induced MSCs (Ind).

<p>Values are given as the mean of three measurements ± SEM.</p