Cold injury of the rat skin. A fluorescence histochemical study of adrenergic nerves, mast cells and patency of cutaneous blood vessels.

Abstract

In order to investigate the pathogenesis of frostbite a combined trypan blue and catecholamine fluorescence method was adopted for studying changes in cutaneous adrenergic nerves, mast cells, the patency of blood vessels, the distribution of blood flow and vascular permeability after experimental cold injury. The skin of rats was frozen with a copper cylinder precooled in liquid nitrogen. The rats were investigated 1/2, 4, 8, 16 and 24 h or 2, 4, 7, 9 and 14 days after freezing. Trypan blue has a red fluorescence when absorbed onto proteins. In normal skin this stain was seen inside the blood vessels and in the dermal tissues. Bluegreen fluorescent adrenergic nerves were seen in the erector pili muscles and around arteries and arterioles. The fluorescence of the mast cells was yellow. In the specimens taken half an hour after skin freezing most of the adrenergic nerves appeared morphologically normal. Degenerative changes were observed in the mast cells varying from degranulation and diminution of yellow ...