Decreasing Hippocampal Apoptosis and Improvement of Spatial Memory After High-Intensity Interval Training in Male Adult Diabetic Rats
Description
to this aim, 48 eight-week-old male Wistar rats with 150 ± 10 g weight were categorized in 4 groups: control (n=12), diabetic (n = 12), exercise diabetic (n=12), exercise (n = 12). Peritoneal injection of STZ so-lution (50 mg / kg) was used to induce diabetes. After familiarization with the environment and training for a week, HIIT protocol was performed 3 times/week for 6-weeks, with 50-110% vo2max intensity. MWM protocols were applied to assess spatial memory and learning. Finally, BDNF, FOXO-1, CASPASE-3 gene expression was evaluated by using Real Time PCR technique. . High intensity interval training The HIIT started after the animals were acclimatized and familiarized with the exercise training with the intensity of 30-50% of VO2max (According to Høydala, 2007 article) within a three-day period. The repetitions during the three sessions were ranged from 6 to 8 repetitions in one minute with 2-min rest between the sets. As shown in figure, the main HIIT protocol was progressive during six weeks (3 sessions a week) (50-110% VO2max) (53). The HIIT started with a 5-min warm-up (45- 50% VO2max). The rats performed 10 repetitions of a 1-min run. However, the speed and degree of incline varied from week to another week, and 2- min inactive rest time be-tween the sets. Time-to-exhaustion The time-to-exhaustion test was performed on two groups (HIIT & DIIT) to com-pare pre- and post-training results. The rats run on the treadmill as the speed gradual-ly increased to evaluate time, distance and speed with respect to their performance. To start, the treadmill was set at the speed of 10m/min with a fixed incline of zero and the speed increased by 2m/min for every 2 min until the rats were exhausted or the maxi-mum speed was achieved. The result of the post-test indicated that the rats improved their performance. Morris water maze is a circular pool (150 cm diameter, 60 cm height) which was divided into four quadrants and was filled with water (20±1 °C, 55±5% humidity), es-cape platform, and camera which was suspended above the maze and recorded escape latency, distance to reach the platform, and the percentage of time which rat spent in target. Then, the surface of escape platform was covered in a fixed position of 1 cm under the water. The MWM was in the laboratory surrounded by various signs. Each rat was given 8trials per day for 3 consecutive days. Each release point was randomly changed for every trial. To be accustomed to the maze, the mice were placed in water without platform for three minutes to swim three hours before training. Each trial lasted until the rat discovered the hidden platform or for a maximum duration of 60 seconds and then it was to rest on it for 30 seconds. if rat which failed to find the plat-form, it was placed on the platform by the experimenter. To assess memory retention, a spatial probe test was performed in 4th day, and the platform was removed from the maze. Each rat spent 60 seconds searching for the water maze.