To observe stromal cell-derived factor-1alpha (SDF-1a) combined with Integra scaffold promoting wound healing of full-thickness skin defects, and to explore its mechanism.

Thirty healthy male C57 mice aged 6-8 weeks were selected to make round full-thickness skin defect wounds with diameter of 1 cm on both sides of their spine symmetrically. The dermal scaffold Integra was used as the wound cover. The symmetrical wounds of thirty mice on the back were randomly divided into two groups: SDF-1a group and control group, with 30 wounds in each group. SDF-α was injected subcutaneously into the wound in the SDF-1α group, while phosphate buffer solution was subcutaneously into the wound in the control group. On days 3, 6, 12, 18 and 24 after operation, the wound healing time and contraction were observed, and the wound and surrounding tissue samples were taken for hematoxylin-eosin staining and immunohistochemical staining to observe the infiltrating cells, granulation tissue thickness and vascularization. Data were processed with t test.

(1) The complete healing time of wounds in SDF-1a group was (15.7±1.6) days, significantly shorter than that in control group[(19.6±1.8) days], and the difference was statistically significant (t=3.967, P<0.05). (2) The wound healing contraction rates in SDF-1a group were (7.3±3.3)%, (14.7±8.4)%, (27.6±6.3)% respectively on days 3, 6 and 12 after operation, while those in control group (8.3±2.5)%, (17.5±6.4)%, (31.2±16.5)%. There were no statistical significant difference between the two groups (t=0.6427, 0.262, 0.208; with P value above 0.05). The wound healing contraction rates in SDF-1a group on days 18 and 24 after operation [ (36.6±6.7)%, (58.2 ±7.1)% ] were lower than those in control group[ (67.6±10.7)%, (81.1±8.3)% ]. The difference was statistically significant (t=2. 463, 2.094; with P value below 0.05). (3) The number of infiltrating cells per high-power field on day 3 after operation in SDF-1a group were (181.7±28.8), compared with those in control group were (190.8±33.4), there were no statistical difference (t=4.08, P>0.05). The number of infiltrating cells per high-power field on day 6 after operation in SDF-1a group were (382.2±43.4), compared with those in control group (478.2±38.8). There were statistical difference (t= 6.20, P<0.05). (4) The thickness of granulation tissue in SDF-1a group was (255.82±41.8) μm, (387.6 2±36.8) μm on day 6 and 12 after operation, which were smaller than those in control group [ (407.3±43.4) μm, (490.2 ± 49.4) μm]. The differences were significant (t=4.08, 6.159; with P value below 0.05). (5) The wound healing condition in SDF-1α group was consistent with normal skin on day 24 after operation, while the scar was apparent and the epidermis was thin in control group. (6) The density of CD3 and CD31 positive cells in the granulation tissue in SDF-1α group was slightly higher than that in control group on day 12 after operation. The vascular density of the granulation tissue in SDF-1α group was significantly higher than that in control group.

Local use of SDF-1alpha can promote the vascularization of granulation tissue in full-thickness skin defect wounds and improve the effect of wound repair.