Aging abolishes circadian rhythms of RORa and antioxidant enzymes expression in the temporal cortex of free running rats

CORIA LUCERO, CINTIA; ANZULOVICH, ANA CECILIA; NAVIGATORE-FONZO, LORENA; LACOSTE, MARÍA GABRIELA; DEYURKA, NICOLÁS

Merlo

Congreso; XXXV Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2017

RORa is a transcription factor that binds RORE motifs in the promoter of clock Bmal1 and other target genes. Antioxidant enzymes contribute to the cellular redox state which is crucial for the molecular clock function. Previously, we showed that antioxidant enzymes activity follow a daily variation in the temporal cortex (TC), which was abolished in aged rats. Herein our objectives were: 1) to investigate endogenous rhythms of catalase (Cat), glutathione peroxidase (Gpx) and Nrf2 genes expression and RORá protein levels inthe rat TC, and 2) to evaluate whether aging could affect those temporal patterns. Three- and 22-month-old male Holtzman rats were maintained under constant darkness for 15 days before the experiment, in order to validate the endogenous nature of circadian rhythms. TC samples were isolated every 4 h during a 24h period. RORá protein levels were assessed by inmunoblotting. Cat, Gpx and Nrf2 mRNA levels were determine by RT-PCR. Specific softwares were used to circadian analysis. We observed circadian endogenous rhythms of RORá, Cat and Gpx expression in the TC of young free running rats (Chronos fit, p