2.6. Behavioral tests

Four behavioral tests were performed to evaluate the motor functions. All the mice underwent the four tests with an interval of 1 h between each test.

Mice were placed on the rotarod and then tested at a speed of 30 rpm for up to 120 s on the revolving rod. The time when the mice first fell off the rod was automatically recorded by the rotarod, which was designated as latency. Each mouse was tested three times. Between each trial, mice were allowed to rest for 1 h.

The pole includes a 50 cm wooden pole (3 cm in diameter) and a wooden ball. The base of pole was positioned in the home cage and the wooden ball was fixed on top of the pole to prevent mice from sitting on the top and to help position the mice on the pole. The performance of mice descending the pole was scored by a scale of 0–5. The mice were pretrained before experimentation. Each mouse performed three trials with an interval of 1 h.

Mice were placed into a clean cage and allowed to move freely for 3 min before the test for acclimation. Round adhesive stickers were attached to the front paws of the mice with slight pressure. Then they were placed back into the cage and time for each mouse to completely remove the stickers was recorded. Three trials were administrated for each animal and they were allowed an interval of 30 min between each trial.

The front paws of the mice were made to grasp the horizontal rope (about 5 mm in diameter). Then they were observed and assigned a score from 0 to 5, which was based on the following criteria: 0, dropping from the rope within 10 s; 1, gripping the rope with one front paw; 2, gripping the rope with both front paws; 3, gripping the rope with one hind paw; 4, gripping the rope with both hind paws; 5, attempting to escape to the end of the horizontal rope. The test was performed three times for each mouse with an interval of 1 h.