| Burn is one of the special traumas of skin. Only superficial burn wound can healspontaneously and its healing depends on the extent of destroied skin. One of the main tasksfor burn surgeons is to improve the speed and quality of wound healing. However, themechanism of wound healing has not yet been illuminated completely. Epidermal stem cells(ESCs) are known as a kind of resident stem cells in skin, which localize in the basal layerof epidermis, or the bulge of hair follicle. The ESCs play an important role in maintainingskin metabolism and accerating wound healing. It is believed that the migration of ESCsfrom their niche to wound is one of the key initial steps in wound healing.In our previous studies, P311expression was found in early granulation tissue andhypertrophic scars. It may suggest that P311participate in wound healing after burn injury.Moreover, some researchers have found that P311could enhance the migration of fibroblastand glioblastoma. Therefore, we presume that P311may promote burn wound healingthrough accelerating the migration of ESCs.Material and methods:1. Co-localization of P311expression and ESCs in mouse superficial second degreeburn wound.18male C57BL/6mice were divided randomly into a control group without injury and5injury groups with superficial second degree burn on the backs. Burn wound tissue andnormal skin samples were harvested at hour6,12,24,48and72, and P311expression indifferent phase points was tested by immunohistochemistry. BrdU was injected into infantC57BL/6mice peritoneally to label ESCs by retention labelling method. Burn wound tissuewas havseted on day3after the mice were given superficial second degree burn on theirbacks at week7. Immunohistochemistry double stain was performed to observe therelationship between P311expression and localization of epidermal stem cells in vivo.2. The migration of ESCs accelerated by P311in a wound model in vitro.The plasmid pAdEasy-P311, an adenovirus vector to express P311, was constructed and identified successfully. Human epidermal stem cells were isolated and cultured by themethod of rapid adhesion to collagen Ⅳ. The cultured P2hESCs were infected withpAdEasy-P311or its control vehicle pAdEasy-Myc, respectively. The cell migration areaswere measured in scratch wound assay at hour0,12,24,36,48and72post-injury. Datawas processed with independent samples T test.Result:1. P311expression was upregulated in burn wound and over expressed in ESC ofneo-skin.It was found that there was no P311expression in normal skin, while the expression inthe injured tissues was changed in different parts and different phase points. P311wasfound to be expressed in the wound, neo-epidermis and hair follicles after burn injury byHIC. On the other hand, the expression at the edge of the wound increased at hour6and12after injury, then decreased to normal level. More important, it was found that P311expression co-localized with the BrdU-labelled ESCs in neo-skin.2. P311could accelerate the migration of ESCs in vitro.The cultured ESCs could express P311highly after infected with pAdEasy-P311, andit was found that the migration distance increased significantly in the scratch wound assaycompared with the control vector. At hour12,24,36,48and72after the scratch, it wasobserved that the ESC in P311group migrated much quicker than that in the controlgroup.All the corresponding p values were less than0.01.Conclusions:Our data indicate that P311sould play an important role in wound healing throughenhanceing the migration of ESCs after injury and provide a new insight into theunderstanding of mechanism of wound healing. |
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