Biologia, Bratislava, 55/Suppl. 8: 107-111, 2000.

ISSN 0006-3088 (Biologia). ISSN 1335-6399 (Biologia. Section Cellular and Molecular Biology).

 

Full Paper

Toxic effect of hyperglycaemia on rat aortic function and structure: effect of L-arginine.

 

Ruzena Sotnikova1*, Ludmila Okruhlicova2, Jana Navarova1, Milan Stefek1, Andrej Gajdosik1 & Alena Gajdosikova1

1 Institute of Experimental Pharmacology, Slovak Academy of Sciences., Dubravska cesta 9, SK-84216 Bratislava, Slovakia; tel.:++ 421 7 59410659, fax: ++ 421 7 54775928, e-mail: exfarosa@savba.sk

2 Institute for Heart Research, Slovak Academy of Sciences., Dubravska cesta 9, SK-84216 Bratislava, Slovakia

* corresponding author

Received: July 10, 2000 / Accepted: October 24, 2000

 

Abstract

This work was designed to determine the influence of 6-month hyperglycaemia induced by streptozotocin (STZ) on the reactivity and ultrastructure of the rat aorta. Further, the effect of L-arginine on hyperglycaemia-induced functional and ultrastructural changes was studied. In the functional study, responses to 1 nM – 0.1 mM acetylcholine, 100 mM KCl, 1mM noradrenaline, and 20–100 mM hydrogen peroxide were evaluated under isometric conditions. Hyperglycaemia evoked diminution in acetylcholine-evoked endothelium-dependent relaxation and increase in noradrenaline- and hydrogen-peroxide-induced contraction. Functional changes were accompanied with a decrease of glutathion in aortic homogenates. Ultrastructural examination of the diabetic aorta showed disturbances in normal tissue organisation. L-arginine produced an improvement of acetylcholine-induced vasodilatory response, partial recovery of the noradrenaline- and hydrogen-peroxide-evoked contractile responses and of glutathion level in the aorta. In L-arginine-treated diabetic rats, endothelial and smooth muscle cells exhibited mostly normal appearance, without considerable defects.

 

Key words: streptozotocin, hyperglycaemia, rat aorta, functional studies, electron microscopy, L-arginine.