Histological framework of lymphatic vasa vasorum of major arteries: an experimental study.

We investigated the histological framework of lymphatic vasa vasorum of major arteries in the rabbit and guinea pig combining the "natural filling method" with light and transmission electron microscopy. An absorbing adventitial lymphatic network consisting of large and sparsely distributed vessels with capillary structure occupied a more external arterial wall position than blood capillaries. The latter were smaller, more numerous, densely distributed, and located closer to the arterial lumen at the media-adventitial border. Periarterial lymphatics (with the structure of absorbing lymph vessels) encircled the wall of the major arteries and formed a rich and irregular plexus. The topography and anatomic structure of these absorbing lymph vessels suggest that lymphatic drainage plays a significant role in large arterial wall homeostasis.