[Treatment with interleukin-2 ameliorates endothelium-dependent vasorelaxation of aorta in streptozotocin-induced diabetic rats].

Aim: To investigate the changes in aortic functions in streptozotocin(STZ)-induced diabetic rats and the effect of interleukin-2 (IL-2) on them, we observed the vasorelaxation of aorta to acetylcholine(ACh) and sodium nitroprusside(SNP).
Methods: Male Sprague-Dawley rats were randomly divided into a normal control group, an IL-2 control group, a diabetic group, and diabetic groups administered with a low dose (5 x 10(3) U x kg(-1) x d(-1), s.c.) or a high dose of IL-2 (5 x 10(4) U x kg(-1) x d(-1), s.c.) for five weeks. Aortic rings were isolated for use in vitro isometric force recording studies, and endothelium-dependent relaxation induced by ACh and endothelium-independent relaxation induced by SNP were measured. The serum nitric oxide (NO) levels and the activities of serum superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) were measured.
Results: ACh caused a dose-dependent relaxation that was weakened in the diabetic group. The IL-2 treated groups were less weakened. However, the endothelium-independent relaxation induced by SNP was not significantly different in aortae of all groups. The serum NO levels were significantly increased in diabetic rats treated with IL-2 when compared with diabetic group, but the serum SOD and GSH-PX activities were not improved in diabetic group with IL-2.
Conclusion: IL-2 can improve the aortic endothelium-dependent relaxation in diabetic rats, which involved the improvement of endothelial function in aorta, other than the alteration of anti-oxidative capacity.