Fig. 2

L-PRP and P-PRP induce TSC differentiation into tenocytes. Morphology of TSCs after 14 days in culture (a-c). In the control (a), cells were cobblestone-shaped, a typical feature of TSCs. But PRP treatment changed cell morphology into more elongated tenocyte-like cells and increased the cell numbers (b, c). Immunostaining for the stem cell marker nucleostemin (NS) (d). NS staining was positive in the control (d - pink dots) but negative in the PRP-treated cells (e, f). Quantitative reverse transcription-polymerase chain reaction analysis (g, h). Expression of the stem cell marker gene, Oct-4, was reduced in PRP-treated cells (g); however, PRP-induced changes on the expression of non-tenocyte genes, Sox-9, Runx-2, and PPAR-γ, were minimal (h). Gene expression levels were normalized with respect to the expression GAPDH (glyceraldehyde 3-phosphate dehydrogenase). Asterisks indicate significant differences (P < 0.05) when compared with the control. Statistical analyses were performed by using t test with a sample size of at least three in each group. All analyses were performed on cells in culture for 14 days. Bars = 100 μm (a-f). L-PRP leukocyte-platelet-rich plasma, P-PRP pure-platelet-rich plasma, PRP platelet-rich plasma, TSC tendon stem/progenitor cell