Effects of paradoxical sleep deprivation on blood parameters associated with cardiovascular risk in intact and ovariectomized rats compared with male rats

The purpose of this study was to investigate the effects of paradoxical sleep deprivation (PSD) on circulating lipoproteins (total cholesterol, HDL, LDL and triglycerides) in males as well as in intact and ovariectomized (OVX) female rats. The intact female rat group was sub-distributed according to the phase of the estrous cycle (proestrus, estrus and diestrus) allowing for comparison of the lipid profile with males and OVX rats. The results indicate that PSD significantly reduced cholesterol in intact females compared to OVX and male rats; it reduced triglycerides in all goups except in diestrus rats and increased HDL levels in male rats compared with the respective controls. PSD also increased LDL levels in male and OVX rats when compared to intact females. Examinations of cholesterol fractions revealed significant increases in HDL in control-OVX animals when compared to the other groups, whereas HDL was significantly increased after PSD in male rats. Such results suggest that the cardiovascular response in intact, OVX females and male rats is differentially regulated especially when such are submitted to PSD. Similarities in blood parameters observed between OVX and male rats are likely due to the suppression of ovarian hormone release after ovariectomy. (c) 2006 Elsevier B.V. All rights reserved.