Aging disrupts the temporal organization of antioxidant defenses in the heart of male rats and phase shifts circadian rhythms of systolic blood pressure

• Published in: Biogerontology (Dordrecht) Vol. 22; no. 6; pp. 603 - 621
• Main Authors: Altamirano, Fernando Gabriel, Castro-Pascual, Ivanna Carla, Ferramola, Mariana Lucila, Tula, Marina Luz, Delgado, Silvia Marcela, Anzulovich, Ana Cecilia, Lacoste, María Gabriela
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.12.2021; Springer Nature B.V
• Subjects: Aging; Antioxidants; Biomedical and Life Sciences; Blood pressure; BMAL1 protein; Cardiovascular diseases; Catalase; Cell Biology; Circadian rhythm; Circadian rhythms; Developmental Biology; Enzymatic activity; Gene expression; Geriatrics/Gerontology; Glutathione peroxidase; Heart; Life Sciences; Oscillations; Oxidative stress; Research Article; Risk factors; Rodents; Transcription; Ultradian rhythms; Ventricle; Young adults; Heart; Aging; Blood pressure; Circadian rhythm; Antioxidant enzymes
• ISSN: 1389-5729; 1573-6768
• DOI: 10.1007/s10522-021-09938-7

Aging is one of the main risk factors for cardiovascular diseases, and oxidative stress is a key element responsible for the development of age-related pathologies. In addition, the alteration of circadian rhythms also contributes to cardiovascular pathology, but the underlying mechanisms are not well defined. We investigated the aging consequences on the temporal patterns of antioxidant defenses, the molecular clock machinery, and the blood pressure, in the heart of male rats maintained under constant darkness (free running) conditions. Male Holtzman rats from young adult (3-month-old) and older (22-month-old) groups were maintained under constant darkness (12-h dark:12-h dark, DD) condition during fifteen days before the experiment. After the DD period, heart ventricle samples were isolated every 4-h throughout a 24-h period. We observed circadian rhythms of catalase (CAT) and glutathione peroxidase (GPx) mRNA expression, as well as ultradian rhythms of Nrf2 mRNA levels, in the heart of young adult rats. We also found circadian oscillations of CAT and GPx enzymatic activities, reduced glutathione (GSH) and BMAL1 protein in the same group. Interestingly, aging abolished the rhythms of CAT and GPx enzymatic activities, phase-shifted the rhythm’s acrophases of GSH and BMAL1 protein levels and turned circadian the ultradian oscillation of Nrf2 expression. Moreover, aging phase-shifted the circadian pattern of systolic blood pressure. In conclusion, aging modifies the temporal organization of antioxidant defenses and blood pressure, probably, as a consequence of a disruption in the circadian rhythm of the clock’s transcriptional regulator, BMAL1, in heart.