Maternal Methyl-Enriched Diet Normalizes Characteristics of the Sleep–Wake Cycle and Sleep Spindles in Adult Offspring of WAG/Rij Rats with Genetic Absence Epilepsy

Abstract

It has been previously shown that the perinatal maternal methyl-enriched diet (MED) reduces the number of spike-wave discharges (SWDs) and behavioral symptoms of depression in the adult offspring of WAG/Rij rats. Epilepsy and depression are usually accompanied by disturbances in the sleep-wake cycle. SWDs and sleep spindles are different manifestations of thalamocortical activity It is assumed that pathological alterations in the thalamocortical system that lead to SWD also change the sleep spindles. It is possible that the maternal MED has a positive effect not only on the SWD, but also on the sleep spindles. The purpose of this work is to find out whether maternal MED affects the sleep-wake cycle and whether it changes the characteristics of sleep spindles in adult offspring of WAG/Rij rats. It has been shown that in the offspring of WAG/Rij rats born to mothers who consumed MED during the perinatal period compared to the offspring whose mothers consumed control diet (CD), the relative duration of REM sleep significantly increases. In the offspring of WAG/Rij rats whose mothers consumed MED, the relative duration of REM sleep and the number of its episodes become indistinguishable from those in non-epileptic Wistar rats. Maternal MED also increases the number of transitions from slow-wave to REM sleep. There is a significant negative correlation between the number of SWDs and the duration of REM sleep. Maternal MED compare to CD decreased the amplitude and spectral power density of sleep spindles. They became much closer to the amplitude and spectral power of density of sleep spindles in Wistar rats. Thus, maternal MED normalizes characteristics of the sleep-wake cycle and sleep spindles in adult offspring of WAG/Rij rats. We hypothesize that this positive effect is associated with a reduction in the symptoms of absence epilepsy and comorbid depression, as well as with the correction of the activity of the thalamocortical system.