Aerobic physical training restores biomechanical properties of Achilles tendon in rats chemically induced to diabetes mellitus.

UNLABELLED: The aim of this study is to evaluate if the application of a moderate aerobic exercise protocol reverses the damage caused by diabetes on the mechanical properties of the Achilles tendon. METHODS: Forty-four rats were divided randomly into four groups as follows: Sedentary Control Group-SCG, Sedentary Diabetic Group-SDG, Trained Control Group-TCG and Trained Diabetic Group-TDG, the trained groups were submitted to a protocol of moderate physical training on a continuous treadmill. For mechanical testing the tendons were fixed in a conventional mechanical testing machine and pulled to the point of failure of the specimen, the cell load of 500N. The parameters were: Elastic Modulus (MPa), Stress Maximum Strength (MPa), Strain Specific Maximum Force (mm), Energy / Tendon Area (N.mm/mm(2)) and Cross-sectional Area (mm(2)). RESULTS: The evaluation of the biomechanical properties of the Achilles tendon of the SDG indicated that the elastic modulus (MPa) is decreased when compared to the TDG and the other groups (p<0.01). However, the specific deformation (%), the deformation at maximum force (mm), and energy / tendon area (N.mm/mm(2)) of the SDG were significantly higher than in the other groups (p<0.01). Moreover, moderate aerobic training on a treadmill caused the biomechanical property values to move closer to the values shown by the control groups (p>0.01). CONCLUSION: In summary, our study indicates that moderate-intensity aerobic training restored the normal mechanical properties of tendons in diabetic animals, since the elastic modulus (MPa), the specific deformation (%), the deformation of the maximum force (mm) and energy / tendon area (N.mm/mm(2)) approached the values shown by the control groups.

Mechanical properties of achilles tendon in rats induced to experimental diabetes.

The aim of this study was to quantify the effect of chemically induced diabetes mellitus (DM) on the mechanical properties of the Achilles tendon of rats and correlate it with metabolic and biomechanical findings. Adult rats were selected randomly and assigned to two groups, the diabetic group consisted of animals receiving a dose of streptozotocin to induce type I diabetes and the control group. The animals were placed in metabolic cages for analysis of metabolism. Ten weeks after diabetes induction, the Achilles tendon of both groups were collected and submitted to a traction test in a conventional testing machine. The measurements of mechanical properties indicated that the elastic modulus (MPa) was significantly higher in the control group (p < 0.01). In Maximum tension (MPa), the groups did not have differences (p > 0.01). Energy/tendon area (N mm/mm²), specific strain (%) and maximum specific strain (mm) were higher in tendon tests of the diabetic group (p < 0.01). We observed that the mechanical properties of tendons have correlations with metabolic properties of the diabetic animals. These results showed that induced DM in rats have an important negative effect on the mechanical properties of the Achilles tendon.