July - September 2015, Volume 11, Issue 3

Scridon A, Perian M, Vântu A, Ghertescu D, Fisca C, Serban RC

Aortic Rings of Wistar Rats with Streptozotocin-Induced Diabetes Mellitus Display Time-Dependent Changes in Contractility, Endothelium-Dependent and - Independent Relaxation

Acta Endo (Buc) 2015, 11 (3): 276-283
doi: 10.4183/aeb.2015.276

Context. Endothelial and vascular muscle dysfunctions are incriminated in the pathogenesis of diabetes mellitus (DM)-related vascular complications. However, the time-course of these changes remains unclear. Objective. We aimed to assess the time-dependency of changes that occur in vascular reactivity in aortic rings of rats with streptozotocin (STZ)-induced DM with shortversus long-term DM durations and in age-matched controls. Design. Wistar rats were assigned to young control (n=6), young DM (n=9), aging control (n=6), and aging DM (n=8) groups. DM was induced at 11 weeks of age using STZ (60 mg/kg, i.p.). Methods. At the end of the study (15 weeks of age for young controls and diabetics and 38 weeks of age for aging controls and diabetics), KCl - and phenylephrineinduced vascular contractility, and acetylcholine - and sodium nitroprusside (NTP)-induced relaxation were studied to assess endothelium-dependent and –independent vasodilation. Results. Young and aging controls presented similar vascular reactivity parameters. Acetylcholineinduced vasodilation was reduced in both young and aging diabetics compared to age-matched controls. Furthermore, acetylcholine-induced relaxation was significantly lower in aging compared to young diabetics. Meanwhile, NTPinduced vasodilation and both KCl- and phenylephrineinduced vasoconstriction were only diminished in aging diabetics. Conclusions. These results suggest that endothelial dysfunction is an early, progressive, event in the large arteries of diabetic rats that precedes the dysfunction of vessel musculature. The lack of any change in aortic reactivity in aging controls indicates that the changes observed in aging diabetics are probably due to prolonged, severe hyperglycemia, with a negligible participation, if any, of the advancing age.

Keywords: experimental model, Wistar rats, streptozotocin, diabetes mellitus, vascular reactivity.

Correspondence: Alina Scridon MD, University of Medicine and Pharmacy of Tîrgu Mure?, Physiology, 38 Gheorghe Marinescu street Tîrgu Mure?, 540139, Romania, E-mail: alinascridon@gmail.com