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

As we have shown previously, a perinatal maternal methyl-enricheddiet (MED) reduces the number of spike-and-wave discharges (SWDs)and behavioral symptoms of depression in an adult offspring of WAG/Rijrats. Epilepsy and depression are usually accompanied by sleep-wake disorders.SWDs and sleep spindles represent different manifestations of thalamocorticalactivity. It is assumed that pathological alterations in the thalamocorticalsystem that lead to SWD alter sleep spindles as well. Probably,maternal MED has a positive effect not only on SWDs, but also onsleep spindles. The aim of this work was to find out whether maternalMED affects the sleep-wake cycle and whether it alters the characteristicsof sleep spindles in adult offspring of WAG/Rij rats. It has beenshown that in the offspring of WAG/Rij rats born to mothers fedon a MED during the perinatal period, the relative duration of REMsleep significantly increases compared to the offspring whose mothersconsumed a control diet (CD). In the offspring of WAG/Rij rats whose mothersfed on a MED, the relative duration of REM sleep and the numberof its episodes become indistinguishable from those in nonepilepticWistar rats. Maternal MED also increases the number of transitionsfrom slow-wave (non-REM) to REM sleep. There is a significant negativecorrelation between the number of SWDs and the duration of REM sleep.Maternal MED, as compared to CD, reduces the amplitude and spectralpower density of sleep spindles; the latter become much closer tothe amplitude and spectral power density of sleep spindles in Wistarrats. Thus, maternal MED normalizes characteristics of the sleep-wakecycle and sleep spindles in the adult offspring of WAG/Rij rats.We hypothesize that this positive effect is associated with a reductionin the symptoms of absence epilepsy and comorbid depression, aswell as with the correction of thalamocortical activity.