Treadmill running improves motor function and alters dendritic morphology in the striatum after collagenase-induced intracerebral hemorrhage in rats

It is well known that early rehabilitation is effective for functional recovery after intracerebral hemorrhage (ICH); however, the mechanisms have not been well described. The purpose of this study was to elucidate the effects of early rehabilitative therapy (treadmill running) on recovery of motor function and alteration of brain histology after ICH. Male Wistar rats, under deep anesthesia, were placed in a stereotaxic apparatus and injected with collagenase into the left striatum to induce ICH. Sham operated animals were treated with saline. All animals were randomly assigned to treadmill exercise (for 30 min/day, 9 m/min, between 4 and 14 days after surgery) and control and were designated to one of four groups: sham + control (SC), sham + treadmill (ST), ICH + control (IC), ICH + treadmill (IT). Motor deficit score (MDS) was assessed daily after surgery. Volume of tissue lost, dendritic morphology and PSD-95 protein level in the striatum were analyzed at 15 days after surgery. The MDS of IT was significantly improved compared with IC over time. There were no differences between IT and IC in the volume of tissue lost (IT: 63.8%, IC: 61.8%), spine density or PSD-95 protein level in the striatum. However, dendritic length was increased and arborization was more complex in the contralateral striatum of the IT than the IC group (IT: 1226 μm, IC: 937 μm). These data suggest that treadmill running improves motor function after ICH and that improvement may be related to alteration of dendritic morphology in the striatum.