AN EXPERIMENTAL STUDY ON THE VASCULAR LESIONS CAUSED BY DISTURBANCE OF THE VASA VASORUM (III): INFLUENCE OF OBSTRUCTION OF THE VENOUS SIDE OF THE VASA VASORUM AND THE PERIAORTIC VEIN

Abstract

The vena cava inferior segment of young mongrel dogs was injected with 10 per cent gelatin in saline solution to observe the influence of obstruction of the venous side of the vasa vasorum of the aorta and veins in the periaortic tissue. Specimens were taken from the aorta and the extent of vascular lesions were examined at intervals for following 6 months after operation. Degeneration of smooth muscle cells and destruction of elastic fibers were observed in the inner one third of the media at 3rd day-2 weeks after operation. Cystic degeneration suggesting ac-cumulation of plasma in this layer was a characteristics of the degeneration in this period. The internal elastic lamina and elastic fibers in the whole media were also destructed and a gradual increase in thickness of the intima was noticed during 4-26 weeks after operation. Disturbance of plasma flow at the inner one third of the media can be assumed from these specimens. There was no connection between vasa vasorum and lymphatics which can drain plasma, although plasma in the outer coats was able to flow out through the lymphatics abound-antly distributed in this layer. Therefore, it seems likely that stagnation of flow of interstitial fluid in the vascular wall is the principal cause of the vascular lesions as observed in this investigation.