hide
Free keywords:
Chronic unpredictable stress, Glucose intolerance, Metabolic syndrome, PPAR, Lipocalin-2, White adipose tissue
Abstract:
Background: Chronic stress is associated with increased risk of glucose
intolerance and cardiovascular diseases, albeit through undefined
mechanisms. With the aim of gaining insights into the latter, this study
examined the metabolic profile of young adult male rats that were
exposed to chronic unpredictable stress.
Methods: Young adult male rats were submitted to 4 weeks of chronic
unpredictable stress and allowed to recover for 5 weeks. An extensive
analysis including of morphologic, biochemical and molecular parameters
was carried out both after chronic unpredictable stress and after
recovery from stress.
Results: After 28 days of chronic unpredictable stress (CUS) the animals
submitted to this protocol displayed less weight gain than control
animals. After 5 weeks of recovery the weight gain rebounded to similar
values of controls. In addition, following CUS, fasting insulin levels
were increased and were accompanied by signs of impaired glucose
tolerance and elevated serum corticosteroid levels. This biochemical
profile persisted into the post-stress recovery period, despite the
restoration of baseline corticosteroid levels. The mRNA expression
levels of peroxisome proliferator-activated receptor (PPAR)-gamma and
lipocalin-2 in white adipose tissue were, respectively, down-and
up-regulated.
Conclusions: Reduction of PPAR-gamma expression and generation of a
pro-inflammatory environment by increased lipocalin-2 expression in
white adipose tissue may contribute to stress-induced glucose
intolerance.
