engleski

Reduced dietary selenium impairs vascular function by increasing oxidative stress in Sprague-Dawley rat aortas

This study aimed to determine whether low dietary Se content affects the function and mechanisms mediating the vascular relaxation of rat aortas, and to test the role of oxidative stress in observed differences. Male Sprague Dawley (SD) rats were maintained for 10 weeks on low Se (low- Se group ; N=20) or normal Se content (norm-Se group ; N=20) rat chow. Dose responses to ACh (10- 9-10-5M) and the response to reduced pO2 were tested in noradrenaline- precontracted aortic rings in the absence/presence of the NOS inhibitor L-NAME, COX-1, 2 inhibitor Indomethacin and the antioxidative agent Tempol in tissue bath. mRNA expression of glutathione peroxidase 1 (GPx1), catalase (CAT) and Cu/Zn SOD was measured in rat aortas. Oxidative stress (TBARS), antioxidative plasma capacity (FRAP) and protein levels of GPx1 were measured in plasma and serum samples, respectively. Reduced ACh- induced relaxation (AChIR) (dominantly mediated by NO) in the low-Se group compared to the norm-Se group was restored by Tempol administration. Hypoxia induced relaxation (HIR) (dominantly mediated by COX-1, 2), TBARS and FRAP as well as GPx1 serum concentrations were similar between the groups. mRNA GPx1 expression in rat aortas was significantly decreased in the low-Se compared to the norm-Se group. These data suggest that low dietary Se content increases the local oxidative stress level, which subsequently affects the NO- mediated vascular response.

selenium ; vascular function ; endothelium ; oxidative stress ; rats

nije evidentirano