High Cholesterol Diet Induces Obesity in Zebrafish

Authors: C Justin David, R Rajapriya, V Veena, G Kumaresan,
Abstract: Obesity is a non-communicable, multifactorial disorder characterized by relentless differentiation and accumulation of white adipose tissue (WAT) culminating in co-morbidities such as Type 2 Diabetes and cardiovascular disorders (CVDs). Consumption of cholesterol rich diet and lack of physical activity in coordination with Sterol Regulatory Element Binding Proteins (SREBPs), leptin and ghrelin and very recently, MicroRNAs (miRNAs) regulates energy homeostasis, dysregulation of which leads to obesity. Zebrafish has become an excellent vertebrate model for studying metabolic disorders by their genetic homology and visceral organ similarity to humans; amenability to genome editing technologies help generate humanized disease models. We optimized protocols for generating diet-induced obese (DIO) zebrafish model by feeding high cholesterol diet (HCD; 6%) for 6-8 weeks. Feeding HCD for 8 weeks resulted in exogenous obesity confirmed by higher Body Mass Index (BMI) values of obese males (0.059 ± 0.004) and females (0.071 ± 0.007) significantly (P<0.05) higher than the controls (0.047 ± 0.005). Histological analyses of intestine showed increased deposition of lipid droplets (LDs) in obese microvilli than the controls. Diet induced obese (DIO) zebrafish model may aid in unravelling molecular mechanisms underlying obesity.