動脈硬化が脊椎や腰背筋群へ及ぼす影響―遺伝性高コレステロール血症ウサギを用いた実験的研究

Effects of Atherosclerosis in Lumbar Arteries on Back Muscles and Lumbar Discs. : An Experimental Study in Hypercholesterolemic Rabbits

　本研究の目的は，腰動脈に動脈硬化を発症した実験動物を用いて，動脈硬化が腰椎背筋群の血流量低下や変性，および椎間板の変性に及ぼす影響を実験的に明らかにすることである．遺伝性高コレステロール血症ウサギを用い，腰椎部MRI像による多裂筋変性の評価，多裂筋血流量の計測，腰椎椎間板変性の組織学的評価を行い，対照ウサギと比較検討した．その結果，腰動脈の動脈硬化は，腰椎背筋群の変性や腰椎椎間板の変性に有意な影響を及ぼさないが，筋血流量を低下させる傾向があることが明らかになった．

　The aim of this study was to demonstrate the effects of atherosclerosis on blood flow in the lumbar muscles and on muscle and the lumbar disc tissue in experimental animals. Kurosawa and Kusanagi hypercholesterolemic rabbits (KHC rabbits) were used. KHC rabbits spontaneously develop atherosclerosis around the orifices of the lumbar arteries in the abdominal aorta with age. Lumbar MRI images were used to measure signal intensities and cross-sectional areas (CSA) of the multifidus muscles at L5/6 as a means of evaluating muscle degeneration. Blood flow in the multifidus muscles was measured, and the extent of degeneration of the lumbar discs at L5/6 was evaluated histologically. The extent of degeneration of the multifidus muscles and lumbar discs was not significantly different between the KHC rabbits and control rabbits. The development of atherosclerosis of the lumbar arteries with age decreased blood flow in KHC rabbits, but the decrease was not significantly different between younger and older rabbits.