Experimental Studies on Pathogenesis and Treatment of Hypertensive Choroidopathy.

Research Project

Project/Area Number	60570838
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	Ophthalmology
Research Institution	Miyazaki Medical College
Principal Investigator	MASUYAMA Yoshimasa Dpt. of Ophthalmology, Miyazaki Med. College, 医学部, 助教授 (70107902)
Co-Investigator(Kenkyū-buntansha)	MATSUURA Yoshifumi Dpt. of Ophthalmology, Miyazaki Med. College, 医学部・附属病院眼科, 助手 (50173795)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥600,000 (Direct Cost: ¥600,000) Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Keywords	choroid / endothelial cell / hypertension / 高血圧 / 脈絡膜
Research Abstract	The purpose of the study is to elucidate the pathogenesis of vaso-obliteration and evaluate the effectiveness of antiplatelet drugs on hypertensive choroidopathy. Acute hypertension was induced with intravenous injection of metaraminol bitrtrate in adult pigmented rabbits. The eyes were studied with fluorescein fundus angiography, light and electron microscopy. Fluorescein angiography revealed constriction of the choroidal arterioles, filling delay into the choriocapillaris and leakage of fluorescein dye. These lesions predominantly occurred in the posterior retina around the vascular wing, especially in the inferior region of it. On the histopathological studies, choroidal arterioles severely constricted and lost its lumen. These findings indicated ischemia of peripheral basins. Endothelial cells of the choriocapillaris showed hydropic degeneration and desquamation from the subendothelium. The endothelial damages lead to activation of platelet aggregation, thrombus formation and necrosis of the retinal pigment epithelial cells. Electron microscopic tracer(lanthanum nitrate) intravenously injected pass through the necrotic pigment epithelial cells and diffused into the subretinal space. Hypertensive choroidopathy reveals to results the endothelial damages secondary to ischemia. On the effects of the antiplatelet drugs to acute hypertension, platelet-clumping in the peripheral blood was supressed but the occurrence of the choroidopathy was uncontrollable.