DAILY VARIATION OF METABOLIC PARAMETERS ARE MODIFIED IN AN EXPERIMENTAL MODEL OF NUTRITIONAL OBESITY IN ADULT RATS

ALFONSO JO; SALINAS E; GUTIERREZ AGÜERO A; LOPEZ M; DELGADO SM; PEREZ CHACA V; CIMINARI E; BIAGGIO, V.; GOMEZ N; NAVIGATORE FONZO LS; ANZULOVICH AC

MENDOZA

Congreso; XL REUNION CIENTIFICA DE LA SOCIEDAD DE BIOLOGIA DE CUYO; 2022

It is well known that the cause of Obesity (OB) is multifactorial, including genetic, environmental, and dietary factors, among which, highcalorie diets play a central role in the development of the disease. On the other hand, several investigations have related altered metabolichomeostasis and circadian parameters with the Alzheimer disease. As part of the IMIBIO-SL institutional project (P-UE 013), which studiesOB as a predisposing disease to the development of chronic age-associated diseases and the search for early biomarkers with predictivepotential, we obtained a nutritional model of OB in adult rats and analyze potential early biomarkers of Alzheimer disease (AD). In thisframework, our objective here was to evaluate the daily variation of metabolic parameters in our model of OB in adult rats. For this, maleWistar rats were weaned at 21 days of age, and fed a normocaloric diet (NC), containing 366 Kcal of lipids / Kg diet, then, at the 2-moage, they were randomly separated, and fed: one group, with the NC diet (control, CO, group) and the other, with a high fat diet (HFD,1570.7 Kcal of margarine / Kg diet, OB group), for the next 14 weeks. The animals were kept under 12h-light:12h-dark and 22-24 °Cconditions, with water and food ad-libitum. For chronobiological studies, at least four (4) animals from each group were euthanized everysix (6) hours, at the zeitgeber times (ZT): ZT2, ZT8, ZT14 y ZT20. All the experiments were performed following national and internationalguides for the care and use of laboratory animals and were approved by the CICUA (UNSL). Metabolic parameters such as: glucose (G),triglycerides (TG), total cholesterol (TC), HDLc, and LDLc + VLDLc levels, were determined in the serum of both, CO and OB groups,using commercial kits. Statistical differences throughout the 24-h period were analyzed by one-way ANOVA, followed by a post-hoc test,to confirm statistical differences between ZTs within each group; chronobiological statistics were used to confirm the presence of rhythmand Student t test to compare rhythm’s parameters (acrophase, mesor and amplitude) between groups. We found G, HDLc and TG levelsvary significant and rhythmically throughout a day in the serum of the CO group, with rhythms’ acrophases occurring at the beginning ofthe light period. Unexpectedly, TC and LDLc+VLDLc do not display a rhythmic variation throughout a 24-h period. Noteworthy, the HFDabolished the rhythmic patterns of daily G and TG levels and induced oscillating patterns of TC and LDLc+VLDLc levels, with the TCrhythm’s acrophase at the beginning of the day and the lipoproteins’ peak at the second half of the night. Furthermore, daily means of G,TG and LDLc+VLDLc levels increased in the OB group (p