Electron Microscopic Study of Blood-Brain Barrier after Treatment of Hypertonic Solution in Rats

• Published in: Japanese Journal of Pharmacology 1989, Vol.49 (suppl), p.299-299
• Main Authors: Abe, Hideo, Kudo, Seiji, Inokuchi, Kohzoh, Fujita, Koh, Takahashi, Gen
• Format: Article
• Language: English
• ISSN: 0021-5198; 1347-3506
• DOI: 10.1016/S0021-5198(19)56734-8

Previously we reported that methotrexate transfer into rat brain was facilitated after the pretreatment with hypetronic mannitol solution, and this effect was augmented by addition of vasodilators or surface active agents. Using the electron microscope (EM), we determined the relationship between structural changes and functional changes of capillary endothelial cells, as a component of the blood-brain barrier (BBB), after drug treatments. Method：Male wistar-Kyoto strain rats (11 to 14 weeks old) were anesthetized with pentobarbital-Na (30 mg/kg, i.p.). At 5 min before fixation, animals were infused with the test solutions into the right internal carotid artery (5 ml/min, 30 sec) A mixed solution of 2.5% glutaraldehyde and 0.05% tannic acid in 0.1 M Na-cacodylate buffer (pH 7.4) was infused into rat brain through the aorta cannulated via the left ventricle (120 cm H2 O, 60 min). Removed specimens of the right parietal lobe were fixed with 1% OsO4 , 2% tannic acid, and 1% OsO4 and 1.5% ferrocyanide in Na-cacodylate buffer (pH 6.8), stained with lead aspartate in s-collidine (pH 5.2), fractured, and dehydrated; and then they were observed by an EM. Results：The capillary endothelial cells in the saline control were shown to have a non-pored surface and cavernulae. The cavernulae in the 20% mannitol-saline group seemed to be increased in number and size as compared to those in the saline control group. These differences may be involved in the increase of BBB permeability after hypertonic mannitol solution treatment.