Dietary Zn deficiency does not influence systemic blood pressure and vascular nitric oxide signaling in normotensive rats |
| |
Authors: | Sato Masamichi Kurihara Nobutaka Moridaira Kazuaki Sakamoto Hironosuke Tamura Jun'ichi Wada Osamu Yanagisawa Hiroyuki |
| |
Institution: | (1) Department of Hygiene and Preventive Medicine, Faculty of Medicine, Saitama Medical School, Saitama, Japan;(2) Department of General Medicine, Gunma University School of Medicine, Gunma, Japan |
| |
Abstract: | Because zinc (Zn) is an important component for cell protection against certain oxygen species, it has been suggested that
Zn deficiency impairs the potent oxidant defense capacity, which is constitutively provided in the vascular system. However,
the influence of dietary Zn deficiency on systemic blood pressure and vascular system is controversial and unclear. We therefore
examine the effect of dietary Zn deficiency on systemic blood pressure, a potent superoxide scavenger, aortic Cu/Zn superoxide
dismutase (SOD) activity, a most representative synthase of the endothelium-derived relaxing factor, and aortic endothelial
nitric oxide synthase (eNOS) expression. Furthermore, the direct effects of intravenous administration of NOS inhibitor, N
ω-nitro-l-arginine methyl ester (l-NAME), and a SOD mimetic compound, tempol, in normotensives were tested in Wistar-Kyoto (WKY) rats. A Zn-deficient diet (4
wk) contributed to growth retardation, the decrease in thymus weight, and the lower levels of serum Zn compared with the standard
diet group. However, no significant difference in conscious systolic and diastolic blood pressure was found in the Zn-deficiency
group. The administration of l-NAME caused an increase in the mean arterial pressure (MAP) levels in the two groups of rats and the involvement of the vasodilator
nitric oxide (NO) in the regulation of systemic BP in the normotensive state. On the other hand, administration of the superoxide
scavenger, tempol, led to a decrease in MAP levels in the two groups of rats, indicating the participation of the oxygen free
radical, superoxide, in the maintenance of the systemic BP in a normotensive state. There were no significant differences
between the Zn-deficient diet group and the standard diet group in the normotensive state. eNOS expression and Cu/Zn SOD activity
in the aorta were also intact in Zn-deficient normotensive rats. These findings suggest that the 4 wk of Zn deficiency was
inadequate to alter systemic blood pressure and focal NO signaling in the normotensive state. Long-term Zn deficiency affects
the neuronal, immune, and hematopoietic systems, which contribute to systemic and/or local circulation. However, Zn deficiency
alone does not cause hypertension and local vascular dysfunction in the normotensive state. |
| |
Keywords: | Zinc deficiency normotensive rat nitric oxide superoxide Cu/Zn SOD eNOS |
本文献已被 PubMed SpringerLink 等数据库收录! |
|