Research Progress on the Relationship among Circadian Rhythm, Melatonin and Aging

It is generally believed that aging is a gradual decline in the efficiency of our biological metabolism, which eventually leads to the deterioration of individual physiological function and the development of a series of age-related degenerative diseases.The circadian clock machinery orchestrates the normal metabolism of the organism in order to assure that individual growth,development and reproduction are adapted to the changes of diurnal environmental variations. The circadian rhythm in the elderly is attenuated with age and is accompanied by the onset of metabolic syndrome, the accumulation of genomic or epigenomic instability, the decline of metabolic tissue homeostasis and the change of natural feeding behavior. Existing results corroborate that light at night(LAN) and melatonin inhibition affect genomic integrity and normal metabolic function. In several animal models,LAN accelerated aging by inhibiting melatonin production in the pineal gland and promoting age-related carcinogenesis. This paper reviews the effects of the circadian rhythm on aging and discusses the complex relationship among circadian rhythms, melatonin and aging in different models of organisms, which may provide clues for prolonging human life and maintaining health.