Role of endogenous irisin, a novel myokine, in cognitive functions and insulin sensitivity in exercised diabetic rats

Gamal, Maha M.; Tork, Ola M.; Eshra, Mohamed A.; Magdy, Shimaa; Rashed, Laila A.

doi:10.4103/1687-4625.195886

Role of endogenous irisin, a novel myokine, in cognitive functions and insulin sensitivity in exercised diabetic rats

Authors

10.4103/1687-4625.195886

Abstract

Background
Irisin, an exercise-induced myokine, has broad implications for metabolism and energy homeostasis. The aim of this work was to investigate the irisin expression and its receptor and the signaling pathway in relation to cognitive functions to allow for a better understanding of its role in an exercised diabetic model.
Materials and methods
A total of 40 adult male albino rats were divided equally into four groups. The first group included control rats (the control group). The remaining animals were used to establish a type 2 diabetic model and were further divided into the following: the diabetic sedentary group; the chronic exercised diabetic group; and the acute exercised diabetic group. At the end of the study period, the behavioral assessment was carried out for all groups in a T-maze. After scarification, gastrocnemius muscles, whole brains, and abdominal adipose tissues were excised for the measurement of gene expression of muscle , brain , (), brain MAPK and adipose tissue uncoupling protein 1 (), and MAPK. In addition, insulin sensitivity indices and serum lipid profile were measured for the studied groups.
Results
Muscle irisin expression was significantly elevated in chronic and acute exercised diabetic rats ( < 0.001) compared with diabetic sedentary rats. Significant positive correlations existed between the muscle mRNA expression patterns compared with the brain expression, , brain MAPK ( = 0.878, 0.933, and 0.908, respectively; < 0.001 for all), as well as cognitive performance together with an improvement in insulin sensitivity and lipid profile. On the other hand, although muscle was correlated positively with adipose MAPK, it was negatively correlated with .
Conclusion
Our results suggest that raised muscle levels for both types of exercise are involved in the improvement of cognitive functions and insulin sensitivity in diabetic rats. However, further studies should clarify its precise role in relation to fat browning.

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