Brain oxidative stress induced by recurrent obstructive apneas: Old versus young rats

Abstract

Background:Obstructive sleep apnea (OSA) is over 50% in elderly population and cognitive impairment is a well-known consequence. It has been reported that both oxygen partial pressure (PtO2) and oxidative stress increase during recurrent apneas in brain tissue of young rats(Almendros et al. Sleep, 2011;34:1127–1133). It has also been recently demonstrated a lower mean increase and a decrease in PtO2 swings amplitude during apneas in older rats (ATS,2013), but it is not known whether this pattern translates into brain oxidative stress. Aim: To measure the brain oxidative stress in response to obstructive apneas in young and old rats. Methods: This study was carried out on 40 male Wistar rats: 20 young (12-weeks old) and 20 old (18-months old). The rats were non-invasively subjected to recurrent obstructive apneas (50 apneas/h, 15 s each) over 4 hours. Brain tissue samples were excised for measurement of the content of lipid peroxidation (LPO), using an Assay Kit, and antioxidant enzyme levels were determined by Western Blot. Results: LPO signifi cantly increased after apneas in young (p<0.01) but not in old rats. Superoxide dismutase, glutathione peroxidise-1, and gluthatione reductase increased after apneas, especially in the old rats (p<0.05)