Middle-distance running and DNA damage in diabetics

Background: Physical activity is an essential part of prevention and therapeutic management in diabetes. Nevertheless, doubts remain as to whether endurance sports may contribute to worsen an enhanced oxidative DNA injury, frequently observed in diabetics. Methods: The study population consisted of 19 euglycemic and 16 diabetic amateur runners (9 with type 1 and 7 with type 2 diabetes), who were engaged in a 21.1 km running trial. Blood samples for analysis of DNA damage with phosphorylated histone protein H2AX (γ-H2AX) foci assessment were collected before the run and 3 hours afterward. Results: The values of γ-H2AX foci parameters at rest were similar in diabetic and euglycemic athletes. Although type 2 diabetics displayed a trend toward higher values of all γ-H2AX foci parameters at rest compared to type 1 diabetics, in no case such difference reached statistical significance. A substantial increase of all γ-H2AX foci parameters was observed after the 21.1 km running trial, both in euglycemic and diabetic subjects, but the absolute increases were non-significantly different between the two study groups. Interestingly, the absolute increase of cells with γ-H2AX foci was slightly but not significantly higher in type 2 than in type 1 diabetics, whilst the values of γ-H2AX foci/cell and total γ-H2AX foci exhibited an absolute increase that was significantly higher in type 2 than in type 1 diabetics. The difference was no longer significant after correcting γ-H2AX foci parameters for age. Conclusions: The burden of DNA injury at rest in physically active diabetics is comparable to that of a population of euglycemic recreational athletes and the extent of DNA damage in diabetics engaged in middle-distance running is non-significantly different from that observed in euglycemic athletes.