Abstract
Aging has been recognised to be a major risk factor for the development of cardiovascular and neurodegenerative diseases and growing evidence suggests a role for oxidative stress. A Nox2-containing NADPH oxidase has been reported to be a major source of reactive oxygen species (ROS) generation in the vascular system and in the brain. However, the role of Nox2 enzyme in aging-related metabolic disorders and vascular neurodegeneration remains unclear. In this study, we used age-matched wild-type (WT) and Nox2-deficient (Nox2 -/- ) mice on a C57BL/6 background at young (3-4 month) and aging (20-24 month) to investigate the role of Nox2 in aging-related oxidative stress, metabolic disorders and cerebral vascular dysfunction. There was an aging-related increase in blood pressure in WT mice (126 mmHg for young and 148 mmHg for aging) (P<0.05); however the blood pressure was well maintained without significant change in Nox2 -/- aging mice. Compared to young WT mice, WT aging mice had significantly high levels of fasting serum insulin and this was accompanied with delayed clearance of glucose (P<0.05) indicating insulin resistance. In contrast, there was no indication of insulin resistance for Nox2 -/- aging mice. We then examined aging-related brain oxidative stress. Compared to WT young mice, there were significant increases (2.7±0.7 folds) in the levels of ROS production by WT aging brain tissue homogenates as detected by lucigenin-chemiluminescence and DHE fluorescence. Increased ROS production in WT aging brain was accompanied by a significant increase (1.8±0.3 folds) in the Nox2 expression detected mainly in the microglial cells (labelled by Iba-1) and decreases in brain capillaries (labelled by CD31) (2.4±0.8 folds) and neurons (labelled by Neu-N) (2.9±0.5 folds) (all P<0.05). Knockout of Nox2 abolished aging-associated increases in brain ROS production and significantly reduced the aging-related pathophysiological changes in the brain. In conclusion, aging-associated metabolic disorders play a crucial role in aging-associated Nox2 activation and vascular neurodegeneration. Nox2-containing NADPH oxidase represents a valuable therapeutic target for oxidative stress-related brain microvascular damage and neurodegeneration.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Arteriosclerosis, Thrombosis, and Vascular Biology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
