Electron microscopic study of vascular regeneration in rat tracheal mucosa following physical curettage

Transmission and scanning electron microscopic studies were made of regeneration of the vascular network of rat tracheal mucosa on 30 min to 8 hr after the mechanical curettage. The vascular network casts were made by infusion of Mercox resin through the aortic arch for scanning electron microscopy. At 30 min after curettage, vascular thromboses were observed, and terminal blind branches were formed in the injured blood vessels areas through SEM observation. Diapedesis of leukocytes appeared at 30 min after curettage from intact venules at the wound margins. Recovery from the loss of endothelial cells began at 30 min after curettage. At 3 hr after curettage, vascular indentation (protrusion) and vascular process (bud-like process) were developed from intact venules at the wound margins. It is concluded that the formation of thrombus and terminal blind branch vessels constitute the initial reparative reactions of the injured vascular network and that new vessels then begin to form by outgrowth of protrusions and bud-like processes from intact venules at the wound margins.