The potential role of stromal cell-derived factor-1α/CXCR4/CXCR7 axis in adipose-derived mesenchymal stem cells.

To investigate the potential role of stromal cell-derived factor-1α (SDF-1α)/CXCR4/CXCR7 axis in adipose-derived mesenchymal stem cells (ADSCs), quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was employed to screen the effective small interfering RNA against CXCR4 and CXCR7 in ADSCs. The messenger RNA (mRNA) and proteins abundances of AKT (p-AKT), ERK (p-ERK), JNK (p-JNK), and p38 (p-p38) in different groups were identified by qRT-PCR, western blot, and immunofluorescence staining method. Meanwhile, cell migration and cell proliferation with SDF-1 treated were examined by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and transwell permeable assay, respectively. Moreover, the interaction between CXCR4 and CXCR7 was examined by a GST pull-down assay. CXCR4 small interfering RNA3 (siRNA3) and CXCR7 siRNA3 have been proved to the most effective tools for knockdown CXCR4 and CXCR7 expressions. mRNA abundance of JNK and p38 could be affected by SDF-1α/CXCR4/CXCR7 axis. However, western blot analysis of p-AKT, p-ERK, p-JNK, and p-p38 in CXCR43-treated ADSCs was significantly higher than that in the control group. Moreover, the immunofluorescence staining analysis revealed that the expressions of p-ATK and p-JNK proteins were significantly higher in NC- and SDF-1-treated subgroups than that in the CXCR4 and CXCR7 groups. p-ATK and p-JNK proteins in CXCR4 group were similar to that in CXCR7 group. Cell migration analysis of CXCR4-treated ADSCs suggested that knockdown CXCR4 could effectively promote cell migration (p < .05). Moreover, CXCR4 could interact with CXCR7. The results in this study could provide a better understanding of SDF-1α/CXCR4/CXCR7 axis during ADSCs development.

[Effect of tranilast on wound healing and administration time on scar hyperplasia of deep partial-thickness burn in mice].

Objective: To investigate the effect of tranilast on wound healing and the mechanism of inhibiting scar hyperplasia in mice, and to study the relationship between the inhibiting ability of tranilast on scar hyperplasia and administration time. Methods: Sixty-six Kunming mice were selected to build deep II degree burn model, and were randomly divided into the control group (18 mice), the early intervention group (18 mice), the medium intervention group (18 mice), and the late intervention group (12 mice). The mice in the early intervention group, the medium-term intervention group, and the late intervention group were given tranilast 200 mg/(kg·d) by gastrogavage at immediate, 7 days, and 14 days after burn respectively, and the mice in the control group were managed with same amount of normal saline every day. The wound healing was observed regularly. At 14, 28, and 42 days in the early and medium intervention groups and at 28 and 42 days in the late intervention group, fresh tissues were taken from 6 mice to observe the shape of mast cells by toluidine blue staining, collagen content by Masson staining; the collagen type I and collagen type III content were measured to calculate the I/III collagen content ratio by immunohistochemistry method, the contents of transforming growth factor ß 1 (TGF-ß 1) and histamine were detected by ELISA; and the ultrastructure of fibroblasts was observed under transmission electron microscope. Results: There was no significant difference in wound healing time between groups ( F=1.105, P=0.371). The mast cells number, collagen content, TGF-ß 1 content, histamine content, and the I/III collagen content ratio in the early intervention group were significantly less than those in the other groups ( P<0.05). Significant difference was found in mast cells number, collagen content, and histamine content between control group and medium or late intervention group at the other time points ( P<0.05) except between control group and late intervention group at 42 days ( P>0.05). Compared with the control group, the activity of fibroblasts in the early intervention group was obviously inhibited, and the arrangement of the fibers was more regular; the fibroblast activity in the medium and late intervention groups was also inhibited obviously. Conclusion: Tranilast has no obvious effect on the wound healing time in mice. Tranilast intervention shows the inhibitory effect on the scar hyperplasia which can significantly reduce the number of mast cells, the content of histamine and TGF-ß 1, inhibit the ability of fibroblasts synthetic collagen and adjust the proportion of collagen synthesis. The immediate tranilast intervention may have the best inhibitory effect on scar hyperplasia.

Stromal cell-derived factor 1 promoted migration of adipose-derived stem cells to the wounded area in traumatic rats.

BACKGROUND: Adipose-derived stem cells (ADSCs) were effective in treating wound. Stromal cell-derived factor-1 (SDF-1), a chemokine usually called CXCL12, is well known for its chemotaxis in induction of cell migration. However, little is known about the SDF-1responsible for the complex migration of ADSCs from residence to injured sites. OBJECTIVE: Herein, we firstly showed SDF-1 is a major regulator involved in migration of ADSCs during wound repair in vivo. METHODS: Trauma in rats was induced by surgical operation. The levels of SDF-1 in wounded tissue were assayed by ELISA. ADSCs were labeled with Green Fluorescent Protein (GFP), and then were transferred to injured rats by intracarotid injection. The plasma levels of ADSCs during wound healing were detected by flow cytometry, and ADSCs in injured tissue were evaluated by bioluminescence imaging in vivo and laser confocal microscopy (LCM), respectively. RESULTS: ADSCs were successfully labeled with GFP. SDF-1 level reached to the peak value on 24 h after injury and then decreased continuously. Additionally, levels of plasma ADSCs in SDF-1 treated rats reached to the peak value (12%) at d21 after medicine delivery, while those of normal and injured rats showed the peak values of 6.28% and 9.84% at d7 and d21, respectively. Finally, the results of LCM indicated treatment of ectogenic SDF-1 obviously enhanced GFP-ADSCs distribution in wounded tissues. CONCLUSION: Our results indicated that SDF-1 treatment obviously promoted the migration and directed distribution of ADSCs in traumatic tissue.