We investigated the effects of diabetes, physical training, and their combination on the gene expression of cardiac muscle. Mice were divided to control (C), training (T), streptozotocin-induced diabetic (D), and diabetic training (DT) groups. Training groups performed 1, 3, or 5 weeks of endurance training on a motor-driven treadmill. Muscle samples from T and DT groups together with respective controls were collected 24 hours after the last training session. Gene expression of cardiac muscles were analyzed using Affymetrix Gene chip MG U74Av2 (Affymetrix , Inc., Santa Clara, CA).
Keywords: time course
Overall design: Experiment was performed on 10 to 15 weeks old male NMRI mice (Harlan, Holland) housed in standard conditions (temperature 22°C, humidity 60 ± 10 %, artificial light from 8.00 am to 8.00 pm, normally 5 animals per cage). Animals had free access to tap water and food pellets (R36, Labfor, Stockholm, Sweden). Animals were randomly divided into healthy and diabetic groups. The diabetic group received a single peritoneal injection of streptozotocin (STZ, Sigma-Aldrich, France, 180 mg/kg) dissolved in sodium citrate buffer solution (0.1 mol/l, pH 4.5) to induce experimental diabetes similar to type 1. The other group received injection of an equal volume of buffer. Diabetes was confirmed 72 hours after the injection by urine glucose testing (Glukotest(r), Roche, Germany), and mice were characterized diabetic when urine glucose values were greater than 200 mg/dl. Diabetic and healthy animals were randomly assigned into 12 groups (n = 5 per group), which were sedentary or trained for one, three or five weeks. Training groups performed 1 hour per day of treadmill running at 21 m/min and 2.5° incline. After one day of familiarization on a rodent treadmill, the mice ran as described above 5 days per week. Mice were sacrificed 24 hours after the last training bout (respective sedentary controls at the same time) by cervical dislocation followed by decapitation. Cardiac muscle was removed, weighed, snap frozen in liquid nitrogen and stored at -80°C for further analysis.
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