Ultrastructural Changes of the Ventricular Choroid Plexus of the Rat following Irradiation on the Head

Ko, Jeong Sik; Choi, Sook Kyung; Ahn, E Tay; Park, Kyung Ho; Kim, Jin Gook

Abstract

Acute irradiation effects on the choroid plexus were studied. Healthy male rats (Sprague Dawley) were anesthetized with sodium thiopental, and were placed on the table of Mistubishi linear accelerator ML-4MV. The rats were irradiated on their heads and necks with the doses of 3,000 rads or 6,000 rads. Six hours, 2 days and 6 days following the irradiations, rats were sacrificed by perfusion fixation through the heart, with 1% glutaraldehyde-1% paraformalde-hyde solution. Choroid plexuses of lateral ventricles were taken out and fixed in the same fixative overnight, and were postfixed in 2% osmium tetroxide solution. Fixed tissue blocks were dehydrated within series of alcohol and acetone, and were embedded in araldite mixture. Ultrathin sections were cut, and contrasted with uranyl acetate and lead citrate solutions, and observed with electron microscope. The results obstained were as follows : 1. Choroid epithelial cells of irradiated rats exhibited severe alterations of their organelles concerning intracellular material transport; such as disappearance of microvilli and basal infoldings, reduction of invaginating pits on the basal and apical plasma membranes, reduction of transfer vesicles, shrinked Golgi complexes, etc. 2. In choroidal epithelial cells of the rats exposed with doses of 6,000 rads, the morphological alterations of the intracellular transport system were more severe than those of the rats exposed with doses of 3,000 rads. 3. Cellular elements and collagen fibrils within the pericapillary space were not so much affected following irradiations. 4. Zonula occludentes in between choroidal epithelials cells were not altered after the irradiations. The above results indicate that the production of cerebrospinal fluid by choroid plexus is severely reduced. Since the choroid plexus functions not only the secretions but it also concerns the homeostasis of many important ions, neuromodulaters, and other peptides, heavy irradiation on the head may result severe malfunction of central nervous system and humoral homeostasis.