Effects of Exercise on Dopamine Expression and Motor Recovery in Hemorrhagic and Ischemic Stroke Rat Models With Comparable Brain Lesions

This study investigated the differential effects of identical treadmill exercise regimens on motor function recovery, lesion volume, and dopamine expression in rat models of ischemic stroke (ISC) and intracerebral hemorrhage (ICH) with comparable brain injury size and location. Thirty male Wistar rats were divided into five groups: ISC, ICH, sham (SHAM), ISC with exercise (ISC + Ex), and ICH with exercise (ICH + Ex). ISC and ICH lesions were induced in the left striatum using endothelin-1 and bacterial collagenase, respectively. Rats in the exercise groups underwent treadmill running (11 m/min, 30 min/day) from postoperative day 4 to 27. Motor function was assessed using the rotarod test, lesion volume was measured via Nissl staining, and dopamine expression was analyzed using tyrosine hydroxylase (TH) immunohistochemistry. On postoperative day 28, exercise significantly reduced lesion volume in ISC + Ex compared to ISC but had no effect on lesion volume in ICH + Ex. Motor function improved in ISC + Ex but not in ICH + Ex. However, TH expression was significantly higher in the ICH + Ex group than in other groups, suggesting that dopamine contributes to recovery mechanisms after ICH. Treadmill exercise had distinct effects on ISC and ICH recovery. In ISC, exercise improved motor function and reduced lesion volume. In ICH, it enhanced dopamine expression without improving motor function. These findings suggest that rehabilitation strategies should be tailored to stroke type to optimize recovery outcomes.