Aging Abolishes Circadian Rhythms of RORa and Antioxidant Enzymes Expression in the Temporal Cortex of Free Running Rats"

NAVIGATORE FONZO LS; ANZULOVICH AC; DEYURKA NA; LACOSTE MG; CORIA-LUCERO C

Mendoza Capital

Congreso; XXXVI Reunion Anual de la Sociedad de Biología del Cuyo; 2018

Sociedad de Biología del Cuyo

The retinoid-related orphan receptor α (RORα) is atranscription factor that binds RORE  motifs in  the promoter ofclock Bmal 1 and othcr targct  genes. Antioxidant enzymes contributeto  thc cellular redox statc which is crucial  for the molecular clock fuuction. Previously, we  showed that antioxidant enzymesactivity  follows 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), glutathioneperoxidase (Gpx) and Nrf2  genes expressicn as  well as  RORαprotein levels in  the rat TC,  and 2) to evaluate the agingconsequences on those temporal patterns. Tree- and 22-month-old  maleHoltzrnan rats were maintained under constant darkness for  15 days beforethe experiment, in order to validate the  endogenous nature of circadianrhythms. On  the  experiment day,  TC samples were isolatedevery 4 h during a 24h  period. RORα protein levels were assessed by inununoblotting. Cat, Gpx and Nrf2  mRNA Ievels were dctermined by RT-PCR. Specificsoftware was used to  analyze circadian  rhythms. We  observedcircadian  endogenous rhythrns of  RORα,  Cat and Gpx expressionin the TC of free running young rats (Chronos fit,  p