Fig. 4

Active tenocytes differentiated from TSCs after L-PRP or P-PRP treatment express collagen types I and III. Immunostaining for collagen types I and III (a-f). Both PRP treatments increased the expression of collagen types I and III (pink/red stain), although cells treated with P-PRP stained more intensely for collagen type I and those treated with L-PRP stained more robustly for collagen type III. Nuclei are stained blue with Hoechst 33342. Western blot analysis (g) on total proteins extracted from cells cultured with L-PRP or P-PRP. Collagen I protein band was robust in the P-PRP-treated group; collagen III protein band was more abundant in the L-PRP-treated cells. Semi-quantification of the Western blots by ImageJ (h). Each data point represents at least three independent experiments. Statistical analyses were performed by using t test. Significant differences (P < 0.05) between each treatment and the control are indicated by asterisks. The pound sign indicates significant differences (P < 0.05) between L-PRP and P-PRP treatments. Analyses were performed after 14 days in culture. Bars = 200 μm. Col collagen, GAPDH glyceraldehyde 3-phosphate dehydrogenase, L-PRP leukocyte-platelet-rich plasma, P-PRP pure-platelet-rich plasma, PRP platelet-rich plasma, TSC tendon stem/progenitor cell