Effect of diets with different fat contents on the development of diabetes in female Zucker diabetic fatty rat with leptin mutation

The aim of the study was to develop a diet which causes stable hyperglycaemia and development of diabetes in female Zucker diabetic fatty (ZDF) rats. We also examined whether worsened wound healing is caused only by hyperglycaemia or whether it is caused by more factors. Four types of special diets with a different content of fat were fed to eight groups of 3-7 (fa/fa or fa/+) rats. The following diets were used: H1 (24.6% fat), H2 (33.2%), C13004 (25.6%), and St1 (3.4%). We detected significant diet-dependent changes of weight and concentration of glucose in animals with leptin mutation (fa/fa). All examined indicators were significantly (P < 0.001) higher in (fa/fa) animals compared to the fa/+ ones no matter what diet they ate. All diets with high-fat content caused increased glycaemia, but only the diet with 24.6% fat caused a significant (P < 0.01) increase of glycaemia. Our results have proved that this diet is the most suitable to invoke and keep hyperglycaemia. The diet with 25.6% fat is suitable to invoke stable slightly increased glycaemia (10 mmol/l) and hyperinsulinaemia. On the other hand, the diet with 33.2% fat is unsuitable. We did not observe a significant influence of diet on wound healing. We developed a new diet more suitable for induction of stable hyperglycaemia in female ZDF rats than commercially available mixtures. Our study is the first to present recommendations for adjusting a high-fat diet to produce stable hyperglycaemia and hyperinsulinaemia in the rat model.