Interaction between circadian rhythm and grape seed proanthocyanidins in healthy and obese ratspotential role as a central and peripherical clock synchronizer

Abstract

Biological rhythms play an important role in the physiological and metabolic adaptation of the organism to the time of day, circadian rhythm, or year, seasonal rhythm. External cues or modulators called zeitgebers, such as light or food, play a crucial role in the reprogramming or altering these oscillations. Circadian rhythm disruption due to modern lifestyles such as changes in light/dark cycles or dietary patterns has been related to the development of metabolic disorders. In this context, phenolic compounds such as proanthocyanidins (PACs) have demonstrate to exert beneficial effects on metabolic disorders. Moreover, polyphenols have shown their capacity to modulate some components of the clock system. Indeed, the interaction of phenolic compounds with biological rhythms has been recently pointed out by our group as a potential mechanism involved in their beneficial effects. Then, the aim of this thesis was to elucidate whether PACs act through biological rhythms and to investigate whether these phenolic compounds can restore biological rhythms in different perturbation situations, such as changes in light-dark cycles or in dietary patterns. For this, circadian rhythms of healthy and cafeteria (CAF) diet obese Fischer 344 rats, the effects of different situations of perturbation of these rhythms and the properties of PACs to restore these disruptions were studied. CAF diet caused disruption of central clock genes and alteration of metabolism circadian rhythms. PACs demonstrated to act as zeitgebers mitigating the circadian disruption, notably the restoration of the circadian rhythm of melatonin.