Chemokine (C-X-C motif) ligand 8 enhances the homing ability of human umbilical vein endothelial cells by promoting a paracrine response in mesenchymal stem cells under the high glucose environment / 中国组织工程研究

ABSTRACT

BACKGROUND:Chemokines can promote (MSCs) the secretion of vasoactive factors from mesenchymal stem cel s (MSCs) through paracrine mechanism, which have important role in accelerating angiogenesis. OBJECTIVE:Under the high glucose environment, to the effect of the supernatant of MSCs stimulated by chemokine (C-X-C motif) ligand 8 (CXCL-8) on human umbilical vein endothelial cel s (HUVECs), and to analyze the mechanism of Sonic Hedgehog signaling pathway in the stimulation of CXCL-8 on MSCs. METHODS:Under the high glucose environment, the MSCs supplemented with 100μg/L CXCL-8 were set as CXCL-8 group;the MSCs that were preprocessed with 5μmol/L octyl maleimide for 45 minutes and then stimulated with 100μg/L CXCL-8 were as Shh inhibitor group;the MSCs that were routinely cultured in a high-glucose medium were as control group. The cel supernatant of each group was extracted as conditioned medium (CM) to culture HUVECs, respectively, and these cel s were referred to as CXCL-8 CM group, Shh inhibitor CM group, and control CM group, respectively. Cel counting kit-8, cel scratch and Transwel chamber tests were used to observe the effect of each CM on HUVEC proliferation, apoptosis and chemotaxis. By establishment of a diabetic skin ulcer model in C57BL/6J mice, the CM of each group was used to treat the mouse model to confirm the effects of CXCL-8 stimulated MSCs CM on HUVEC homing and ulcer healing. RESULTS AND CONCLUSION:(1) The experimental results in vitro:compared with the control CM group, CXCL-8 CM group significantly promoted the proliferation of HUVECs, and decreased the apoptosis of HUVECs, the closure rate and migration rate of HUVECs were significantly increased (P<0.01 or P<0.01), and the levels of vascular endothelial growth factor and epidermal growth factor were significantly increased (P<0.01 or P<0.01). Compared with CXCL-8 CM group, however, the above results in the Shh inhibitor CM group showed reverse changes (P<0.01). (2) The experimental results in vivo:compared with the MSCs CM group and Shh inhibitor CM group, the healing effect of diabetic skin ulcer and the number of HUVECs labeled by green fluorescent protein in the CXCL-8 CM group were significantly increased (P<0.01). To conclude, these findings indicate that CXCL-8 stimulated MSCs secrete paracrine factors, vascular endothelial growth factor and epidermal growth factor, through the Sonic Hedgehog signaling pathway under the high glucose environment, which enhance the homing ability of HUVECs.