Correlation of behavioral changes to brain edema and histological changes in rats with intracerebral hemorrhage

Objective To investigate the correlation of behavioral changes to brain edema and histological changes in rats with intracerebral hemorrhage (ICH). Methods ICH was induced by stereotactic injection of type Ⅶ collagenase into the straitum of rats, and the behavioral changes of the rats were assessed within 28 days by forelimb placing test, Berderson's grade and comer turn test. Histological examination of the brain tissue was performed with HE staining, and the brain edema of the rats was measured by dry-wet weight method. Results Behavioral tests of the rats confirmed obvious neurological deficits 2 days after ICH with gradual functional recovery in the following 4 weeks. Histological observation showed the presence of brain injury and evidence of injury repair after ICH. Brain edema was the most evident 2 days after the hemorrhage, which subsided gradually 7 days after ICH. An inverse correlation (r2=- 0.774, P<0.05) was found between forelimb placing score and the severity of brain edema. Conclusion Neural damage and repair occurs in the brain of rats following ICH, and the improvement of the neurological function of the rats is related in the early stage with the alleviation of brain edema, but in later stages, the improvement is associated primarily with histological repair of the neurological damage. Key words: Intracerebral hemorrhage; Behavior; Histology; Brain edema