PREVENTION OF DIABETES IN BB/WOR RATS BY INTRATHYMIC ISLET INJECTION

The objective of this study was to determine whether the intrathymic injection of islets can prevent the development of diabetes in BB/W or rats. Evidence suggests that a failure to induce islet thymic tolerance may be an etiological factor in the development of the disease. It was theorized that the introduction of islets into the thymus might directly induce islet tolerance and thus prevent disease. Islets from diabetes-resistant BB/W or rats were injected into the thymuses of 23 young diabetes-prone BB/W or rats; 25 sham-operated animals served as controls. Results showed that 22 of the 25 control rats became diabetic while only 8 of the 23 experimental rats became diabetic (P < 0.0002). The specific lysis of islet cells by spleen cells from nondiabetic experimental and control rats was comparable and less than the lysis induced by spleen cells from diabetic rats. These data demonstrate that the intrathymic injection of islets into diabetes-prone BB/W or rats is an effective method for preventing the development of autoimmune type I diabetes.