Sleep deprivation decreases lipoprotein lipase and hepatic lipase activities in rat plasma and adrenal glands

Ferran Burgaya., Eva Pardina., David Ricart-Jané and Julia Peinado-Onsurbe

Stress has been related to unfavourable concentrations of lipoproteins that may predispose to cardiovascular disease. In this study, we investigated the possible changes in lipases and lipids in the plasma and tissues of sleep-deprived male rats.
Nine rats were distributed into three groups: control (C), sleep deprived (SD) and sleep deprived/rebound (SDR). The three control rats were sacrificed at the beginning of the dark cycle (20:00 h). The remaining rats were deprived of sleep by gentle handling for 24 h, starting at the beginning of the dark cycle (20.00 h). At the end of this period (20:00 h), three rats were sacrificed (SD) and three rats were allowed to sleep for 8 h (SDR) before being sacrificed (04.00 h). SDR animals slept during the dark cycle and therefore, some interference from the circadian cycle cannot be ruled out.
Stress produced by SD in rats caused a decrease in lipoprotein lipase and hepatic lipase activities in plasma (1.9 and 1.4 times in LPL and HL, respectively, vs C) and the adrenal glands (1.6 and 1.7 times in LPL and HL, respectively, vs C). The rats that rebound after SD did not recover the levels of activity of these lipases, which continued to decline after 8 h.
The lipoprotein profile varied in the SD rats but more significantly in the SDR rats. Very low-density lipoprotein in SD rats significantly increased compared with the Control rats, whereas both very low-density lipoprotein, low-density lipoprotein and high-density lipoprotein significantly decreased in SDR rats with respect to both Controls and Sleep Deprivation rats. Phospholipids and cholesterol increased in stressed rats, whereas triacylglycerides and free fatty acids decreased significantly. The adrenal weight increased in both Sleep Deprivation and SDR rats.
Thus, the acute stress produced by sleep deprivation leads to alterations in the plasma and tissue lipases and plasma lipids, which do not always recover after the cessation of stress.

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