Interleukin-2 protects against endothelial dysfunction induced by high glucose levels in rats.
OBJECTIVE
Interleukin-2 (IL-2) can modulate cardiovascular functions, but the effect of IL-2 on vascular endothelial function in diabetes is not known. We hypothesized that IL-2 may attenuate endothelial dysfunction induced by high glucose or diabetes. So the aim of this study was to investigate the effect of IL-2 on endothelium-response of aortas incubated with high glucose or from diabetic rats and its underlying mechanism.


METHODS
Acetylcholine (ACh)-induced endothelium-dependent relaxation (EDR), sodium nitroprusside (SNP)-induced endothelium-independent relaxation (EIR), superoxide dismutase (SOD) and nitric oxide synthase (NOS) were measured in aortas isolated from non-diabetic rats and exposed to a high glucose concentration and from streptozotocin-induced diabetic rats.


RESULTS
Incubation of aortic rings with high glucose (44 mM) for 4 h resulted in a significant inhibition of EDR, but had no effects on EIR. Co-incubation with IL-2 for 40 min prevented the inhibition of EDR caused by high glucose in a concentration-dependent manner. Similarly, high glucose decreased SOD and NOS activity in aortic tissue. IL-2 (1000 U/ml) significantly attenuated the decrease of SOD and NOS activity caused by high glucose. In addition, EDR declined along with the decrease of serum NO level in aortas from STZ-induced diabetic rats. Injection of IL-2 (5000 and 50,000 U kg(-1) d(-1), s.c.) for 5 weeks prevented the inhibition of EDR and the decrease of serum NO levels caused by diabetes.


CONCLUSIONS
IL-2 significantly ameliorated the endothelial dysfunction induced by hyperglycemia, in which the activation of the NO pathway and SOD may be involved.
Qian
Ling-Bo
LB
Department of Physiology, Zhejiang University School of Medicine, 353 Yan-an Road, Hangzhou 310031, China.
Wang
Hui-Ping
HP
Qiu
Wei-Ling
WL
Huang
He
H
Bruce
Iain C
IC
Xia
Qiang
Q
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000503:physiopathology*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D005947:Glucose / Q000494:pharmacology*; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000494:pharmacology*; D008297:Male; D009569:Nitric Oxide / Q000097:blood; D019001:Nitric Oxide Synthase / Q000378:metabolism; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000494:pharmacology
D007376:Interleukin-2; D014665:Vasodilator Agents; D009599:Nitroprusside; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D013482:Superoxide Dismutase; D005947:Glucose; D000109:Acetylcholine