Sirtuin Expression in Insulin-Sensitive Tissues of Rats with Impaired Glucose Tolerance is not Affected by Resistance Training or Zinc Supplementation.

While physical activity and zinc supplementation have shown benefits in diabetes management, little is known about their effect on less severe glucose homeostasis disorders, such as impaired glucose tolerance. On the other hand, sirtuins have an important role in glucose metabolism and insulin sensitivity, but to date, there is no information about the impact of zinc supplementation or physical activity on their regulation in individuals with impaired glucose homeostasis. The aim of this study was to assess the effect of supplemental zinc, muscle-resistance training, and their combination on the expression of selected sirtuins in insulin-sensitive tissues of rats with impaired glucose tolerance. Thirty male Wistar rats with impaired glucose tolerance were fed a high-fat diet for 12 weeks while subjected to zinc supplementation, resistance training, both, or none. Morphometric and metabolic evaluations were performed at the end of the experimental period, and gene expression of sirtuins 1, 2, 4, and 7 was assessed in liver, gastrocnemius muscle, and white adipose tissue. Results showed that zinc supplementation and/or resistance training did not improve metabolic parameters of rats with impaired glucose tolerance, nor did they affect the expression of selected sirtuins in any of the tissues evaluated. However, the expression of some sirtuins was associated with metabolic parameters in a tissue-specific manner. Additional studies are needed to evaluate whether zinc supplementation and/or resistance training can improve metabolic status or modulate sirtuins expression in advanced stages of impaired glucose homeostasis.