INFLAMMATION: THE HIDDEN LINK BETWEEN OBESITY AND TYPE 2 DIABETES

Abstract

Introduction: Obesity and type 2 diabetes mellitus (T2DM) increasingly share a state of low-grade chronic inflammation that exacerbates insulin resistance and metabolic imbalance, highlighting the importance of deepening the understanding of the inflammatory response in these conditions. Objective: To investigate the inflammatory response in experimental models through the analysis and validation of TNF-α and IL-6 levels, focusing on metabolic control and the prevention of complications. Method: Newborn male Wistar rats were divided into 4 experimental groups: control (vehicle), diabetic (induced with streptozotocin on the 5th postnatal day), obese (induced by reducing the litter size to 3 pups per mother), and their respective control. The control (vehicle) and diabetic groups were followed up to 90 days of age, with periodic evaluations of weight, length, and glucose tolerance test at 80 days, and then euthanized. The control and obese groups were followed up to 240 days, with the same parameters evaluated. After euthanasia, blood was collected from all animals for analysis of serum levels of TNF-α and IL-6. Result: It was observed that TNF-α expression was significantly increased in both obese and diabetic animals compared to their respective controls; in contrast, IL-6 showed a statistically significant increase only in the diabetic group when compared to the vehicle, with no differences in the obesity model compared to the control. Furthermore, a direct comparison between the models showed a greater elevation of TNF-α in diabetic rats compared to obese rats, while IL-6 did not show a significant difference between the two groups. Conclusion: TNF-α in inflammation associated with obesity and T2DM validates its usefulness as a more sensitive biomarker in these experimental models. IL-6 requires further investigation, especially in the context of obesity and also in diabetes in animal models.