CD34 and Skin ulcer: Compared with those mice with PBS administration (denoted as DB-PBS), DB mice with SITF- or SITH-preconditioned CD34+ UCB-HSPCs (denoted as DB-SITF and DB-SITH, respectively) were locally injected, the skin ulcers were efficiently alleviated, and the wound healing was largely accelerated (Figure 6B‒D).