実験的粥状動脈硬化に対するブタ膵臓エラスターゼの生化学的, 病理学的検討

The effects of porcine pancreatic elastase on hypercholesterolemic rabbits have been studied. The lipid levels in plasma and tissues, post heparin lipolytic activity (PHLA) in plasma, serotonin contents and plasminogen levels in plasma, succinyl trialanine p-nitroanilide (Suc-(Ala)₃-pNA) hydrolytic activity in tissues and the susceptibility of aorta to elastolytic hydrolysis were analyzed in normal, cholesterol-fed and cholesterol plus elastase injected group.<br>The results were as follows:<br>1) A rapid increase of the plasma lipids was observed immediately after cholesterol feeding began and the striking increase in the lipid levels of the plasma were mainly due to a large increase of cholesterol in VLDL. A significant decrease of the plasma lipid levels was observed in the elastase injected group.<br>2) The high levels of PHLA were observed in the cholesterol-fed and the elastase injected group compared with that of the normal group, but no significant differences were observed between the cholesterol-fed and elastase injected group.<br>(3) A significant decrease of serotonin contents was observed in the cholesterol-fed group, and the decrease was prevented by the elastase injection.<br>4) The high plasminogen levels were observed in the elastase injected group, compared with those of the other two groups.<br>5) Suc-(Ala)₃-pNA hydrolytic activity in the liver was decreased significantly in the cholesterolfed group, and the administration of elastase prevented the decrease of the activity. The activity in the kideny was increased significantly in the cholesterol-fed and the elastase injected group and the activity in the aorta was decreased in both groups compared with that of the normal group.<br>6) The elution profile of elastolytic aorta hydrolysates with and without serum showed that the pattern in the elastase injected group was similar to that of the normal group whereas the pattern in the cholesterol-fed group was different from the others.<br>7) Pathologically, it was observed that a large amount of the lipids was accumulated in tissues. However, the slight sign of the lipid reduction was seen in the liver and the iris from the rabbits treated with the elastase.