Fig. 1. The experimental timeline.
Treadmill exercise
The treadmill exercise was performed according to previous literature[22]. During the adaptation period, the exercised rats were allocated in the test room for 30 min acclimation, followed by treadmill running for 30 min on 3 consecutive days (first day at 8 m/min; second day at 10/min; third day at 12m/min). Then, those rats were subjected to a treadmill exercise protocol at the speed of 12 m/min for 60 min. In total, rats were trained for 1 h per day, 5 days per week, for a total of 4 weeks.
VD model
VD model was induced by bilateral common carotid arteries operation according to previous reported[23]. First, under deep anesthesia with 10% chloral hydrate (350 mg/kg), bilateral common carotid arteries of rats in VD and Exe-VD groups were identified and isolated from vagus through a ventral midline cervical incision, then tightly ligated using 10-0 suture thread on both ends. The rats in the control group were subjected to the same surgical procedure except that the common carotid arteries were exposed but not ligated. The “Zea-Longa 5-point scale” was performed according to previously described methods to verify whether the animal model had been successfully established. A score between 1 and 4 indicates successful modeling of VD. Rats not showing neurological defect were excluded from the study.
Table 1 “Zea-Longa” 5-point scale