Expression of clock-related genes in response to different restricted feeding patterns

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 649-675-Central Regulation of Appetite & Feeding/GI Regulatory Peptides
Bench to Bedside
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-662
Leonardo Domingues Ara˙jo*1, Fernanda Borchers Coeli-Lacchini2, Silvia Ruiz Roa3, Ernane Torres Uchoa4, Lucila Elias1, Ayrton Custodio Moreira2, Paula CL Elias3, Jose Antunes-Rodrigues5 and Margaret De Castro6
1School of Medicine of Ribeirao Preto of University of Sao Paulo, Ribeirao Preto, Brazil, 2School of Medicine of Ribeirao Preto-University of Sao Paulo, Ribeirao Preto-SP, Brazil, 3School of Medicine of Ribeirao Preto- University of Sao Paulo, Ribeirao Preto SP, Brazil, 4University of Sao Paulo-FRMP, Ribeirao Preto-SP, Brazil, 5Univ of Sao Paulo Sch of Med, Ribeirao Preto SP, Brazil, 6Sch of Med of Ribeirao Preto-U, Ribeirao Preto SP, Brazil
Introduction: Anticipating food access is associated to changes in gene expression involved in the biological clock system regulation. However, there are few studies regarding non-photic synchronizers. Objectives: To evaluate the expression of genes involved in the regulation of the biological clock system in hypothalamic nuclei and peripheral blood of animals submitted to different feeding patterns. Material and Methods: Wistar rats were submitted to 3 different dietary patterns for 21 days. Control group (CG): food and water ad libitum, Food Restriction group (FR): food from 1800 to 2000h, and Food Shift (FS): food from 0900 to 1100h. Animals were decapitated at 0900 and 1700h. Blood was collected for corticosterone (B) measurements by RIA. Suprachiasmatic hypothalamic nuclei (SCN), Arcuate (Arc) and Paraventricular nuclei (PVN) were microdissected and RNA was extracted by Trizol. Expressions of Clock, Bmal1, Per1, Per2, Per3, and Cry1, Cry2 genes were determined by qPCR and expressed as 2-ΔΔCT. Results: CG animals showed greater weight (g) and daily food intake (g) compared to FR and FS groups (385.4±55.4 vs 245.5±32.0 vs 227.9±40.9; P<0.0001) and (31.2±3.9 vs 14.1±1.8 vs 13.3±1.6; P<0.0001), respectively. CG animals and FR group showed lower B levels (µg/dL) at 0900 than 1700h (1.0±0.6 vs 14.1±8.1, P=0.0004) and (3.6±2.6 vs 20.7±7.6, P<0.0001), respectively. However, FS group showed higher B levels at 0900 than 1700h (22.7±6.2 vs 10.6±5.7, P=0.0007). There was no difference in the expression of Clock, Bmal1, Per1, Cry1, and Cry2 genes in the SCN of CG animals, but Per2 and Per3 had higher expression at 1700 than 0900h, similar to its B secretion pattern. FS group showed higher expression of Per1 in the SCN at 1700h. There was no difference in Clock and Bmal1 genes expression in the PVN. However, Per1, Per2, Per3 and Cry2 gene expressions were higher in CG animals and FR groups at 1700 than at 0900h. Conversely, FS group lost the pattern observed in these groups and showed higher Per1 expression at 0900h in PVN and Arc nuclei, suggesting an inversion of the expression pattern observed in CG and FR groups. In the PVN and Arc nuclei increased expression of Per1 occurred around feeding time, regardless of the time of food access. Conclusion: Our data suggest that dietary restriction patterns can modulate the expression of clock genes in the PVN and Arq nuclei, which are related to non-photic signals and involved in energy homeostasis and food motivation.

Nothing to Disclose: LDA, FBC, SRR, ETU, LE, ACM, PCE, JA, MD

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Sources of Research Support: FAPESP Grant 2007/58365-3 and CNPQ