Atherosclerosis in the Rat. Effect of X-Ray and a High Fat Diet.

Forty-two albino Wistar rats, average weight 133 g, fed on a supplemented high fat diet, were divided into 2 groups. One group was treated with 2500 r (X-rays) to the thorax, and the other kept on the high fat diet, but not irradiated. The rats were killed 20 to 28 weeks after completion of irradiation. Marked atherosclerotic lesions were observed in the coronary arteries of 38.8% of the irradiated group and in 22.7% in the group on the high fat diet alone. In the pulmonary arteries similar changes were noted in 25% of the irradiated group and none in the unirradiated group. Previous studies showed that in 8–15 weeks post-irradiation marked coronary lesions were present in 26.6% of the irradiated group and none in the unirradiated. It is suggested that X-irradiation accelerates the process that develops with diet and with time.