Poster Presentation ANZOS Annual Scientific Meeting 2021

Effects of individual and combined stress and diabetes/obesity on CNS signalling and depressive phenotype (#222)

Brock Lyon 1 , Makayla Nicholas 1 , Eugene Du Toit 1 , Tessa Helman 1
  1. Griffith University, Gold Coast, QLD, Australia

Introduction: As modern diseases such as depression and obesity become more prevalent, the need for investigations into the role of lifestyle factors in their development becomes more perspicuous. Studies have associated both stress and obesity with depression, however there are currently no studies that explore the role of combined subclinical stress and a highly obesogenic western diet (WD) in the aetiology of depression. Subclinical stress refers to the stress as experienced by people in their everyday life from work, family, or outside worldly events.

Methods: Sixty-four C57BL6/J mice randomly divided into 4 groups (n=16) Control (C), Western Diet (WD), control diet + restraint stress (C+RS), and WD+RS. WD macronutrient content was: 32% fat, 57% carbohydrate, 11% protein and 14% fat, 59% carbohydrate, 19% protein for the control diet. Two-hour restraint per day was used to induce restraint stress (RS) for the last two weeks of the 16-week feeding program used in the study.

Results: Animals fed a WD ate more food than animals fed a control diet. Animals exposed to stress reduced their food intake compared to their control littermates (P>0.0078). At the end of the 16-week feeding program body mass of WD animals were higher than their respective controls (P>0.0001). The WD also increased fasted insulin levels compared to the animals on the control diet (P>0.0001). Analysis of frontal cortex (FC) and hippocampus (HPC) catecholamines shows increased levels of noradrenaline and adrenaline in animals exposed to RS, with the combined WD and RS animals having higher levels of both catecholamines compared to all other groups.

Conclusion: A WD increases food consumption, body mass, and fasted insulin levels while synergistically interacting with restraint stress to increase FC and HPC catecholamines.