Intra-Abdominal Fat Adipocyte Hypertrophy through a Progressive Alteration of Lipolysis and Lipogenesis in Metabolic Syndrome Rats

Nutrients. 2019 Jul 5;11(7):1529. doi: 10.3390/nu11071529.

Abstract

This study evaluates the progressive participation of enzymes involved in lipolysis and lipogenesis, leading to adipocyte hypertrophy in a metabolic syndrome (MS) rat model caused by chronic consumption of 30% sucrose in drinking water. A total of 70 male Wistar rats were divided into two groups: C and MS. Each of these groups were then subdivided into five groups which were sacrificed as paired groups every month from the beginning of the treatment until 5 months. The intra-abdominal fat was dissected, and the adipocytes were extracted. Lipoprotein lipase (LPL), hormone-sensitive lipase (HSL), protein kinases A (PKA), and perilipin A expressions were determined. The LPL and HSL activities were evaluated by spectrophotometry. Histological staining was performed in adipose tissue. Significant increases were observed in blood pressure, HOMA-IR, leptin, triglycerides, insulin, intra-abdominal fat, and number of fat cells per field (p = 0.001) and in advanced glycosylation products, adipocyte area, LPL, HSL activities and/or expression (p ≤ 0.01) in the MS groups progressively from the third month onward. Lipogenesis and lipolysis were increased by LPL activity and HSL activity and/or expression. This was associated with hyperinsulinemia and release of non-esterified fatty acids causing a positive feedback loop that contributes to the development of adipocyte hypertrophy.

Keywords: adipocyte; hormone-sensitive lipase; hypertrophy; lipoprotein lipase; metabolic syndrome; perilipin A.

MeSH terms

  • Abdominal Fat / metabolism*
  • Abdominal Fat / pathology
  • Animals
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Dietary Sucrose
  • Disease Models, Animal
  • Disease Progression
  • Fatty Acids, Nonesterified / metabolism
  • Feedback, Physiological
  • Hyperinsulinism / etiology
  • Hyperinsulinism / metabolism
  • Hypertrophy
  • Lipogenesis*
  • Lipolysis*
  • Lipoprotein Lipase / metabolism
  • Male
  • Metabolic Syndrome / etiology
  • Metabolic Syndrome / metabolism*
  • Metabolic Syndrome / pathology
  • Perilipin-1 / metabolism
  • Rats, Wistar
  • Signal Transduction
  • Sterol Esterase / metabolism
  • Time Factors

Substances

  • Dietary Sucrose
  • Fatty Acids, Nonesterified
  • Perilipin-1
  • Plin1 protein, rat
  • Cyclic AMP-Dependent Protein Kinases
  • Sterol Esterase
  • Lipoprotein Lipase