Assessment of Insulin, GLUT2 and inflammatory cytokines genes expression in pancreatic β-Cells in zebrafish (Danio rario) with overfeeding diabetes induction w/o glucose

J Diabetes Metab Disord. 2021 Oct 2;20(2):1567-1572. doi: 10.1007/s40200-021-00903-2. eCollection 2021 Dec.


Abstract: In recent years, zebrafish have been proposed as a model for rapid analysis of gene function and biological activity due to high genetic similarities with humans. The aim of this study was to determine the effects of overfeeding-induced diabetes w/o glucose on inflammatory cytokine as well as insulin and glucose transporter-2 genes (GLUT2) genes expression in the pancreas in zebrafish.

Materials and methods: The experiment was performed on 120 zebrafish (duplicated sample) with a specific genetic mapping (AB-Wild type). A total of 8 tanks, each containing 15 fish per 2-liter water, were used and divided into four groups: (1) Control group, (2) regular diet with glucose,3) Only Artemia overfeeding and 4) Combined Artemia with glucose. We induced T2DM zebrafish using glucose monohydrate solution in water and repeated daily Artemia feeding. In this model, fasting blood glucose increase is preceded by obesity and glucose intolerance. The experiment lasted for two months. Blood glucose and fish biometrics were measured in two steps. The expression of TNFα, IFNγ, GLUT2 and Insulin genes were quantified by a Real-Time qPCR System (Applied Biosystems, USA) using a set of specific primers.

Results: The highest mortality rate was observed in combined Artemia and glucose (p < 0.05). We showed significantly higher expression of IL-1B and TNF-α as well as inhibitory cytokines such as IFNγ genes in overfeeding induced diabetes(OID) which was highest in the combined Artemia and glucose group.(p < 0.05)The GLUT2 gene expression was higher in the pure artemia group which decreased to a lower level by adding glucose to Artemia in the diet. (p < 0.05). Also, the lowest insulin gene expression was observed in the combined group (p < 0.05).

Conclusions: In zebrafish, diabetes induction with overfeeding and supraphysiological glucose in diet accompanied with higher expression of inflammatory cytokines genes in the pancreas as well as lower insulin and GLU2 genes. These epigenetic factors appeared to initiate pancreatic beta dysfunction alongside insulin resistance and could have a crucial role in the pathogenesis of overfeeding-induced diabetes using primitive animal models.

Keywords: IL-1B gene; Insulin resistance; Obesity-induced diabetes; TNF-α; Zebrafish.