Effect and mechanism of SHED on ulcer wound healing in Sprague-Dawley rat models with diabetic ulcer.

To evaluate the effect of stem cells from human exfoliated deciduous teeth (SHED) upon the ulcer wound healing and evaluate the mechanism underlying the role of SHED in Sprague-Dawley rat models with diabetic foot ulcer. The rats with diabetic ulcer were established and treated with SHED, mesenchymal stem cell (MSC) and PBS, respectively. The expression of vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), matrix metalloproteinase-2 (MMP-2) and MMP9 at both protein and RNA levels was quantitatively measured. The serum levels of VEGF, IL-1β, TNF-1α and IL-10 were detected by ELISA. The remaining tissues were fixed in 4% chloral hydrate for hematoxylin and eosin (H.E) staining and immunohistochemical staining. MSC and SHED administration could reduce ulceration area and accelerate wound healing at 7 and 14 d after treatment as compared with the control group (all <0.05), which were validated by H.E and immunohistochemical staining. Western blot results revealed that the expression levels of VEGF, eNOS, MMP2 and MMP9 proteins in the MSC and SHED groups were considerably up-regulated compared with those in the control group at different time points (all <0.05). The same trend was also observed in the mRNA expression of these cytokines detected by RT-PCR. At 3-d after treatment, no statistical significance was noted in the IL-10 level among three groups, but the IL-10 concentration in the SHED and MSC groups was significantly down-regulated at 7- and 14-d post-treatment (all <0.05). SHED administration, similar to MSCs, could accelerate wound healing, promote angiogenesis and suppress inflammatory responses in rat models with diabetic ulceration.