Drosophila melanogaster as a Model Organism for Obesity and Type-2 Diabetes Mellitus by Applying High-Sugar and High-Fat Diets

Abstract

Several studies have been published introducing Drosophila melanogaster as a research model to investigate the effects of high-calorie diets on metabolic dysfunctions. However, differences between the use of high-sugar diets (HSD) and high-fat diets (HFD) to affect fly physiology, as well as the influence on sex and age, have been seldom described. Thus, the aim of the present work was to investigate and compare the effects of HSD (30% sucrose) and HFD (15% coconut oil) on symptoms of metabolic dysfunction related to obesity and type-2 diabetes mellitus, including weight gain, survival, climbing ability, glucose and triglycerides accumulation and expression levels of Drosophila insulin-like peptides (dIlps). Female and male flies were subjected to HSD and HFD for 10, 20 and 30 days. The obtained results showed clear differences in the effects of both diets on survival, glucose and triglyceride accumulation and dIlps expression, being gender and age determinant. The present study also suggested that weight gain does not seem to be an appropriate parameter to define fly obesity, since other characteristics appear to be more meaningful in the development of obesity phenotypes. Taken together, the results demonstrate a key role for both diets, HSD and HFD, to induce an obese fly phenotype with associated diseases. However, further studies are needed to elucidate the underlying molecular mechanisms how both diets differently affect fly metabolism.

Ginsenosides improve reproductive capability of aged female Drosophila through mechanism dependent on ecdysteroid receptor (ECR) and steroid signaling pathway

“…Exercise ability was evaluated using a negative axis test with maximum crawl path restricted to 12 cm in length. After a 10-min acclimation period in the test tube, female Drosophila were knocked to the bottom of the tube every 1 min then this procedure was repeated 5 times followed by counting of crawling heights of female Drosophila , with assays repeated at least 3 times ( 29 ).…”

Mating activates neuroendocrine pathways signaling hunger inDrosophilafemales

“…Together, this predicts that mated females require significantly more sugar than virgins. However, as excessive sugar negatively impacts fly health 12 , sugar intake must be tightly regulated. Although the sugar to protein ratio influences reproductive output and longevity 8 , the absolute levels of sugar intake of mated females remain untested.…”

Insect Models in Nutrition Research

“…Drosophila is therefore used as a model to study the effects of high-sugar diets (HSD) and high-fat diets (HFD) on metabolism, gut function, behavior, and aging [ 50 ]. Long-term feeding on a HSD and/or HFD leads to obesity in flies, with pathophysiological complications similar to those observed in humans [ 43 , 51 ]. Obesity in flies induced by HFD/HSD is associated with hyperglycemia, cardiomyopathy and a shorter lifespan [ 27 ].…”

“…Drosophila larvae reared on a HSD become hyperglycemic, insulin resistant, and accumulate fat (all indicators of T2DM) when compared with larvae raised on a normal diet [ 56 ]. In a recent study, the effects of HSD (30% sucrose) and HFD (15% coconut oil) treatments were linked to the symptoms of obesity and T2DM, including weight gain, the accumulation of glucose and triglycerides, and the abundance of Drosophila insulin-like peptides [ 51 ]. The study revealed clear differences in the effects of each diet on survival, glucose and triglyceride levels, and the expression of insulin-like peptides, but both diets induced an obese fly phenotype with linked diseases [ 51 ].…”

“…In a recent study, the effects of HSD (30% sucrose) and HFD (15% coconut oil) treatments were linked to the symptoms of obesity and T2DM, including weight gain, the accumulation of glucose and triglycerides, and the abundance of Drosophila insulin-like peptides [ 51 ]. The study revealed clear differences in the effects of each diet on survival, glucose and triglyceride levels, and the expression of insulin-like peptides, but both diets induced an obese fly phenotype with linked diseases [ 51 ]. Similarly, normal fly food (e.g., yeast and corn starch) with 30% coconut oil (HFD) causes high levels of fat deposition and disrupts insulin/glucose homeostasis [ 57 ].…”