The effects of low intensity electromagnetic fields on the reconstruction of full skin loss wounds grafted with human epidermal stem cells

Abstract

Objective To observe the effects of low intensity electromagnetic fields (LIEMFs) in promoting the reconstruction of full skin loss wounds grafted with human epidermal stem cells (ESCs). Methods Fifty nude mice aged 7 to 8 weeks with full skin loss wounds were equally divided into 3 experimental subgroups ( 1 Hz, 10Hz and 50Hz) and two control groups (a cell suspension control group and a blank control group) , with ten mice each. In the 3 experimental subgroups and the cell suspension control group, ESCs separated from human foreskin and cultured in vitro were grafted to the wounds using collagen sponge scaffolds. The experimental subgroups were then stimulated with an LIEMF (magnetic field intensity 5mT) at the appropriate frequency for 30min/day for 15 days. The blank control group was put under the same conditions without the cell suspension and LIEMF. The healing rates of the wounds were observed, and tissue slices were stained and observed under a light microscope. The inner structure of the regenerating skin was observed using transmission electron microscopy. Results The ESCs were successfully grafted. A few human integrin β1 positive stained cells appeared in the regenerating skin. The average healing rates in the experimental subgroups were significantly superior to those of the control groups. Well differentiated epidermis and dermis could be seen in the regenerating skin in all of the experimental groups. The epidermis had more cell layers and was thicker than in the control groups. More desmosome, hemidesmosome and keratin filaments were seen among the epidemic cells of the experimental groups. Conclusions LIEMF promotes the healing of full skin loss wounds grafted with ESCs in nude mice, and can promote complete repair of skin defects and the regeneration of skin function. Key words: Low intensity electromagnetic fields;  Epidermal stem cells;  Transplantation