粥状硬化形成における胸腺の役割

―コレステロール飼育ウサギでの検討―

抄録

We developed a total thymectomy model for the rabbit, and then studied the role of the thymus in experimental atherogenesis. Ten-week-old male Japanese white rabbits weighing approximately 1.9kg were used. After 26 of these rabbits underwent median sternotomy, they were divided into a thymectomy group (group Tx, n=13) and a dummy operation group (group Sx, n=13). Atherosclerosis was induced by administering a 0.5% cholesterol-rich diet, 150g daily.
At 12 weeks after the operation, the average plasma concentrations of cholesterol were 1, 454±374mg/dl in group Tx and 1, 391±388mg/dl in group Sx. The circulating lymphocyte count in group Tx did not decrease after thymectomy, and consequently, no statistically significant difference between the two groups was observed. The percentage of lipid deposition coverage in the aorta was 58.8±14.9% in group Tx and 30.7±7.7% in group Sx (p<0.01). Cholesterol content in the aortic wall was 30.7±13.2mg/g dry tissue in group Tx and 8.2±3.2mg/g dry tissue in group Sx (p<0.01).
Our results suggest that the thymus has antiatherogenic properties.