A Comparison of Motor Functional Recovery and Brain Damage between Striatal Lesions Induced by Ischemia and Hemorrhage in Rats

Pharmacological inhibition of histone deacetylases ameliorates cognitive impairment after intracerebral hemorrhage with epigenetic alteration in the hippocampus

OBJECTIVES

Post-stroke cognitive impairment (PSCI) interferes with neurorehabilitation in patients with stroke. Epigenetic regulation of the hippocampus has been targeted to ameliorate cognitive function. In particular, the acetylation level of histones is modulated by exercise, a potent therapy for patients with stroke.

MATERIALS AND METHODS

We examined the effects of exercise and pharmacological inhibition of histone deacetylase (HDAC) using sodium butyrate (NaB) on cognitive function and epigenetic factors in the hippocampus after intracerebral hemorrhage (ICH) to seek beneficial neuronal conditioning against PSCI. Forty rats were randomly assigned to five groups: sham, control, NaB, exercise, and NaB plus exercise groups (n=8 in each group). Except for those in the sham group, all rats underwent stereotaxic ICH surgery with a microinjection of collagenase solution. Intraperitoneal administration of NaB (300 mg/kg) and treadmill exercise (11 m/min for 30 min) were conducted for approximately 4 weeks starting 3 days post-surgery.

RESULTS

ICH reduced cognitive function, as detected by the object location test, accompanied by enhanced activity of HDACs. Although exercise did not modulate HDAC activity or cognitive function, repetitive NaB administration increased HDAC activity and ameliorated cognitive impairment induced by ICH.

CONCLUSIONS

This study suggests that pharmacological treatment with an HDAC inhibitor could potentially present an enriched epigenetic platform in the hippocampus and ameliorate PSCI for neurorehabilitation following ICH.

Comparison of motor function recovery and brain changes in intracerebral hemorrhagic and ischemic rats with similar brain damage

In this study, we compared the mechanisms of brain recovery in intracerebral hemorrhage and ischemia, focusing on synapses, glial cells, and dopamine expression, which are considered fundamental for neural recovery after stroke. Male Wistar rats were divided into intracerebral hemorrhage, ischemia, and sham surgery (SHAM) groups. The intracerebral hemorrhage group was injected with a collagenase solution, the ischemia group was injected with an endothelin-1 solution, and the SHAM group was injected with physiological saline. The motor function of these rats was evaluated using a rotarod test on days 7, 14, 21, and 28 post-surgery. On postoperative day 29, lesion volume was analyzed using Nissl staining. In addition, the protein expression levels of NeuN, GFAP, tyrosine hydroxylase, and PSD95 were analyzed in the striatum and motor cortex. There was no significant difference between the ischemia and intracerebral hemorrhage groups in terms of lesion volume in the striatum; however, the motor recovery of the intracerebral hemorrhage group occurred more rapidly than that of the ischemia group, and the intracerebral hemorrhage group exhibited higher GFAP protein expression in the motor cortex. The rapid motor recovery in intracerebral hemorrhage rats relative to that in ischemia rats may be associated with changes in astrocytes in brain regions remote from the injury site.

Very Early Exercise Rehabilitation After Intracerebral Hemorrhage Promotes Inflammation in the Brain

BACKGROUND

Very early exercise has been reported to exacerbate motor dysfunction; however, its mechanism is largely unknown.

OBJECTIVE

This study examined the effect of very early exercise on motor recovery and associated brain damage following intracerebral hemorrhage (ICH) in rats.

METHODS

Collagenase solution was injected into the left striatum to induce ICH. Rats were randomly assigned to receive placebo surgery without exercise (SHAM) or ICH without (ICH) or with very early exercise within 24 hours of surgery (ICH+VET). We observed sensorimotor behaviors before surgery, and after surgery preexercise and postexercise. Postexercise brain tissue was collected 27 hours after surgery to investigate the hematoma area, brain edema, and Il1b, Tgfb1, and Igf1 mRNA levels in the striatum and sensorimotor cortex using real-time reverse transcription polymerase chain reaction. NeuN, PSD95, and GFAP protein expression was analyzed by Western blotting.

RESULTS

We observed significantly increased skillful sensorimotor impairment in the horizontal ladder test and significantly higher Il1b mRNA levels in the striatum of the ICH+VET group compared with the ICH group. NeuN protein expression was significantly reduced in both brain regions of the ICH+VET group compared with the SHAM group.

CONCLUSION

Our results suggest that very early exercise may be associated with an exacerbation of motor dysfunction because of increased neuronal death and region-specific changes in inflammatory factors. These results indicate that implementing exercise within 24 hours after ICH should be performed with caution.