3. Characterization of the human scapholunate ligament cell populations and blood vessels
In order to determine the phenotype of the cells found at the different regions of the SLIL, we first carried out an immunohistochemical analysis of S100 expression. As shown in Figure 6 and Table 2, our results show that the zones that were more enriched in S100-positive cells was M1, followed by D2 and M2, whereas the zone with lower content of positive cells was D1. Differences between D1 and the rest of SLIL zones were statistically significant, as well as the differences between P1 and D2 and M1 and between P2 and D2 and M1. Then, we analyzed the expression of the undifferentiation marker CD73, and we found that all regions contained cells showing positive signal for this marker, although the highest number of positive cells corresponded to D2, and the lowest, to P2. Differences between D2 and D1, P1 and P2 were statistically significant (Figure 6 and Table 2).
In order to evaluate the distribution of the blood vessels in the SLIL, we quantified these structures in each zone of the SLIL, after staining each vessel by CD34 immunohistochemistry. As shown in Figure 6 and Table 2, our analysis revealed that blood vessels were abundant in D1, D2, P1 and P2, but were very scarce in M1 and M2. Differences between M1 or M2 and the rest of zones were statistically significant.