Microvascular density changes during wound-healing.

Vessel densities of arterioles, capillaries, venules and A-V anastomoses were determined during wound-healing following implantation of the rabbit ear chamber. Arterioles were defined on the basis of the direction of blood flow and the presence of a muscular coat. Capillaries were endothelial cell tubes with single-file flow of erythrocytes. Venules were thin-walled vessels collecting blood flow from capillaries and carrying blood flow from the tissue. A-V anastomoses were thick-walled, unbranched vessels carrying blood flow from an arteriole to a venule. Arteriolar density was relatively higher in the earlier stages but venular density was higher in the later stages of wound-healing. The fractional density was highest 2 weeks after implantation for arterioles (17.9%), at 4 weeks for capillaries (39.3%), and at 10 weeks for venules (56.9%). No significant change was observed in the density of A-V anastomoses. This study suggests that the rates of growth and decay are different among each vessel category during wound-healing.