| Burn injury is a kind of special trauma, which characterized by skin defect. Wound management is the main challenge in burn therapy, how to cover and repair the wound as early as possible is the ultimate task of burn surgeon. Many researchers have found that the physiological wound healing depend on the proliferation and differentiation of residual Epidemal Stem Cells (ESsC), especially in the bulge of hair follicle. Usualy, ESCs stay quienscencely in their specific niches. Only when ESCs initiate to migrate from their niches under certain stimuli to wounds, they can proliferate massively and differentiate to terminal cells to repair or regenerate the wounds. Therefore, the migration of ESCs from their niche is one of the key initial steps in the burn wound healing.In previous studies, it was found that the keratinocyte and macrophages could generate high level of Nitric Oxide (NO) in or around the burn wound during the wound healing procedure. Especially, amount of NO was detected in the wound within the early phase after burn injury. Moreover, literatures shown that NO could enhance migration of endothelial cell, broachi epidermal cell and other kinds of cells. However, there is no study to be about the effect of NO on the migration of ESCs. So the effect of NO on the migration of a keratinocyte cell line, HaCat cell, and its possible mechanism were addressed in this study.Material and methods:HaCat cells were cultured in the presence of SNP at different concentrations(0μmol/L, 100nmol/L, 1μmol/L, 10μmol/L, 100μmol/L). The cell migrations were assayed at hour 6, 12, 24, 48 after scratched. Meanwhile, the cytoskeletons of the cultured HaCat cells were observed under confocal laser scanning microscope after stained with Rhodamine-Phalloidin. The expressions of integrin beta 1,Rho,Rac1 and Cdc42 of the cultured cells were determined at mRNA and protein levels by RT-PCR and West Blotting, respectively. Finally, some inhibitors and antagonists were used to enhance or decrease the function of cGMP or PKG, after that, the effects of NO on migration, cytoskeletons, expressions of integrin beta 1 and Rho GTPase were detected as above.Result:It was found that the migration ratio of HaCat cell could be increased by SNP in a dose-dependent manner in the concentration ranges from 0 to 10μmol/L. After the cells were cultured with 10μmol/L SNP for 24 hours, the migration ratio increased from 63% of the control group to 83% (p<0.05). The stress fibers in the cells became thicker compared with the control group, and there were more pilus on the SNP treated HaCat cell. Moreover, Rho, Rac1 and Cdc42 was upregulated at mRNA or protein level after the cells were treated with SNP; while, the expressions of integrin beta 1 were decreased. After add some interference factor of cGMP, we found inhibitor and antagonist, but the accelerator have any effect on it.Conclusion:Our data indicated that NO enhance significantly the migration of HaCat cell in vitro. The changed cytoskeletons and the downregulated Rho GTPase and integrin beta 1 may be involved in this process.
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