Zinc content in the diet affects the expressional changes of cu/znsod in aorta of spontaneously hypertensive rats

Oxidative stress induced by reactive oxygen species (ROS) plays an important role in development of hypertension. Vascular cells have a complex antioxidant system for protection against increased oxidative stress. Zinc is a co-factor of one of the most important antioxidant enzyme – copper-zinc superoxide dismutase (Cu/ZnSOD). The aim of the present study was to examine the effects of feeding different Zn containing diets (40, 60, 160 mg Zn/kg lab chow) on the activity and expression of Cu/ZnSOD in aorta of male (n=27) spontaneously hypertensive rats (SHR). The diets were introduced at the beginning of the development of hypertension (2 months after birth) and the animals were fed for 8 weeks. Cu/ZnSOD expression was analyzed by immunohistochemistry and the activity was measured by RANSOD kit (RANDOX). Atomic-absorption spectrometry was used to determine Zn and Cu concentrations in the rat’s sera. Cu/ZnSOD was mainly expressed in medial smooth muscle cells and it had a weak immunoreactivity in the endothelium. In the group with Zn supplementation diet (160 mg Zn/kg lab chow), Cu/ZnSOD staining was more enhanced in the smooth muscle cells and endothelium, and the systolic blood pressure was significantly decreased. Scripta Scientifica Medica 2007;39(2):137-141