"Effect of an I.C.V. injection of amyloid beta peptide (1-42) on the 24h rhythms of lipid peroxidation and GSH in the rat hippocampus".

NAVIGATORE FONZO L; DEYURKA N; GARRAZA M; ANZULOVICH A

San Miguel de Tucumán, Tucumán, Argentina.

Congreso; Tercera Reunión Conjunta de Sociedades de Biología de la República Argentina.; 2015

Asoc. de Biología de Tucumán, Soc.de Biología de Córdoba, Soc. de Biología de Cuyo y Soc. Argentina de Biología

Alzheimer´s disease (AD) is aneurodegenerative disorder that leads to memory loss, dementia, and death.  Accumulation of Aβ peptide causes an increasein intracellular reactive oxygen species (ROS) and free radicals associated toa deficient antioxidant defense system. Besides oxidative stress and cognitivedeficit, AD patients show alterations in their circadian rhythms.  Previously, we showed that injection of Aβ(1-42) phase shifts CAT and GPx daily rhythms in the rat hippocampus.Continuing with that study, the objective of this work was to investigate theeffects of an i.c.v. injection of Aβ(1-42) peptide on temporal patterns of lipid peroxidation andglutathione (GSH) levels, as well as on Aβ protein levels, in therat hippocampus. Four-month-old males Holtzman rats were divided into twogroups defined as: control (CO) and Aβ-injected (Aβ). Rats were maintainedunder 12h-light:12h-dark conditions and received water and food ad libitum. Hippocampus samples were isolatedevery 4 h during a 24h period. Lipid peroxidation and GSH levels weredetermined by colorimetric assays. Aβ protein levels were analyzed byimmunoblotting. We found that i.c.v. injection of Aβ(1-42) increased Aβ peptide content in thehippocampus and phase shifted Aβ, lipid peroxidation and GSH daily rhythms. Thesechanges follow the previouslyobserved changes in daily patterns of antioxidant enzymes activity. Thus,elevated Aβ peptide levels alter temporal patterns of oxidative stress-relatedparameters and, consequently, would negatively affect cellular clock activityin the hippocampus.