Curcumin mitigates the sleep-deprivation impacts on rat hypothalamic paraventricular nucleus

The paraventricular nucleus of the hypothalamus (PVH) is an important efferent system that relays the circadian rhythm of sleep and stress information to the periphery. Chronic REM sleep deprivation (CSD) is thought to damage this system. We evaluated the effects of CSD after 21 days on the spatial arrangement of PVH in male rats and the anti-apoptotic effects of curcumin on cell loss in sleep-deprived rats.

The rats received 1 mL of 100 mg/kg/day of curcumin in 3 groups: the CSD (through a modified multiple platform apparatus, 18 h/day), grid-floor control, and cage-control along with the same set of matched groups which received 1 mL PBS. In the grid-floor control group, as a control for CSD, animals were placed on stainless-steel-mesh grids positioned upon the CSD apparatus and then allowed to sustain the chance to sleep. After 21 days, their brains were removed for stereological estimations, Voronoi tessellation, and TUNEL assay. In an unbiased stereological approach, Cavalieri's principle and an optical disector were used for estimating the volume and total cell number of the PVH, respectively. The Voronoi tessellation was measured using Image J software.

Significant reductions (P < 0.05) in the PVH volume and cell number, along with an increase in dead neurons, were found in CSD animals. The spatial pattern of two types of PVH neurons (parvocellular and magnocellular) showed random distributions after CSD, whereas curcumin not only increased the volume and neuronal number but also retrieved the spatial distribution to a regular one.

CSD decreased the volume and altered the spatial arrangement of the neurons in PVH by increasing apoptosis and decreasing the cell number. However, oral use of curcumin could protect PVH from these changes.