Suppression of the thermogenic response in a diet-induced obesity model: The role of irisin and uncoupling protein 1

Abstract

Aim: To evaluate irisin and uncoupling protein 1 (UCP1) levels and oxidative stress parameters in an obesity model induced by a cafeteria (CAF) diet that mimics human dietary habits.

Methods: A total of 12 male Wistar rats were divided into two groups: control (n=6) and cafeteria diet (n=6). The control group was fed a standard laboratory diet, while the CAF group was fed a CAF diet consisting of high-calorie foods for 16 weeks. At the end of the experiment, retroperitoneal white adipose tissues (WAT) and brown adipose tissues (BAT) were removed. Tissue irisin and UCP1 levels were determined by ELISA, and total oxidant (TOS) and antioxidant (TAS) status levels were determined by colorimetric methods.

Results: In the CAF group, final body weight, retroperitoneal fat, and brown adipose tissue levels increased significantly compared to the control group (p=0.006, p=0.035, p=0.030, respectively). Irisin and UCP1 levels in BAT were significantly reduced in the CAF group (p=0.001 for both). TAS levels decreased significantly in the CAF group (p=0.010), while the increase in TOS levels was not statistically significant (p=0.655).

Conclusion: The decrease in irisin and UCP1 levels in the cafeteria diet-induced obesity model indicates suppressed thermogenic capacity. The decrease in TAS levels suggests weakened antioxidant defense and increased oxidative stress. These findings suggest that the irisin/UCP1 axis and oxidative stress parameters may be important biomarkers for understanding obesity-related metabolic dysfunction.