Microvascular ultrastructure in non-freezing cold injuries

Abstract

The effects of repeated local exposure to cold on the integrity of the subcutaneous microcirculation were studied in a model using a transparent tissue chamber implanted into a dorsal skin fold of Syrian hamsters. A detailed study of the vascular ultrastructure within the chamber revealed the following features: Endothelial damage was prominent in true capillaries and venous vessels, while arterioles remained unaffected. The endothelial lining appeared extremely attenuated around the entire vascular perimeter causing the development of "gaps", some of which contained leukocytes or platelets. Smaller vessels were often completely filled with blood cells with leukocytes integrated into the endothelial wall. Fibrin was never observed within these occluded vessels. Finally, only veil-like remnants of the endothelium persisted, and compressed erythrocytes were still mimicking the original vascular outline. It is concluded that the ultrastructural changes observed after a repeated non-freezing cold injury closely resemble those observed during ischemia/reperfusion injury.