A Study of Short- and Long-term mRNA Levels of the Retn, Iapp, and Drd5 Genes in Obese Mice Induced with High-fat Diet

Abstract

Adipocyte gene expression is altered in obese individuals through multiple metabolic and biochemical pathways. In this study, we aimed to examine the expression of resistin (Retn), amylin (Iapp), and dopamine receptor domain 5 (Drd5) genes previously suggested to contribute to the pathogenesis of obesity, albeit controversially. We also aimed to determine the effects on short and long-term mRNA levels of these genes in obese mice, induced with high-fat diet (HFD).Two obesity models were created in our study: group T1 (20 mice) was fed with HFD (60% fat) for 3 months, and group T2 (20 mice) was fed with HFD (60% fat) for 6 months. The control group T0 (20 mice) was fed with a diet of 10% kcal fat supplement for 6 months. At the end of the experiment, their adipose tissues were dissected surgically. Tissue samples of each group were pooled for RNA isolation, cDNA synthesis was carried out and the mRNA levels were examined by quantitative real-time polymerase chain reaction. Serum resistin levels were measured using multiplex bead (luminex) technology for validation.In T2 mice, the mRNA expression of Retn showed a moderate up-regulation (fold change=8.32; p=0.0019) in the adipose tissues. Iapp expression was also significantly up-regulated (fold change=9.78; p=0.012). Moreover, a 6.36-fold up-regulation for Drd5 was observed in the adipose tissues of T2 mice (p<0.001). At the same time, serum levels of resistin were found to be high in T1 and T2 mice compared to the control group (p<0.001 and p=0.024, respectively).Our study demonstrated that the mRNA levels of the genetic markers considered to play a role in adipogenesis were different in short- and long-term obesity models formed in C57BL/6J mice using HFD.