2.4. Rotarod Test and Pole Test

The rotarod test and pole test were assessed according to previously published methods [25, 29, 31]. The rotarod test is a useful method for measuring hypokinesia in a mouse model of PD [32]. Mice were evaluated on the rotarod 1 day after the last MPTP injection to assess sensorimotor coordination. The rotarod unit (Ugo Basile, Comerio, Varese, Italy) consisted of a rotating spindle (diameter 3 cm) and five individual compartments, which allowed five mice to be tested simultaneously. After two successive days of twice-daily training (4 rpm rotation speed on the first day and 20 rpm on the second day), the test rotation speed was increased to 25 rpm on the third day in a test session. The time each mouse remained on the rotating bar was recorded over three trials per mouse, at 5 min intervals and a maximum trial length of 300 s per trial. Data are presented as mean time on the rotating bar over the three test trials.

The pole test is a useful method to measure bradykinesia in a mouse model of PD [32]. We performed the pole test on days 5 and 7 after the last MPTP injection. The mice were held on the top of the pole (diameter 8 mm, height 55 cm, with a rough surface). The time that mice needed to turn down completely was recorded as the time to turn (T-turn). The time needed for the mice to climb down and place four feet on the floor was recorded as the time for locomotion activity (T-LA). Each trial had a cut-off limit of 50 s.