Proliferation of neural progenitor cells in the subventricular zone and around the hematoma after intracerebral hemorrhage in adult rat

OBJECTIVE: To examine the proliferation of the neural progenitor cells in the subventricular zone (SVZ) and around the hematoma after intracerebral hemorrhage (ICH) in adult rats. METHODS: ICH was induced by stereotactic injection of type VII collagenase into the corpus striatum of adult rats, followed by pulse or continuous intrapenitoneal injection of bromodeoxyuridine (Brdu) to label the proliferating cells. The rats were sacrificed on days 2, 7, 14 and 28 following the ICH for immunohistochemistry of the tissues in the SVZ and around the hemotoma to determine the number of Brdu- immunoreactive cells. RESULTS: With pulse Brdu labeling, a significant increase in the number of Brdu-immunoreactive cells in the ipsilateral and contralateral tissues in the SVZ and around the hematoma was observed 2-14 days, and the cell number reached the maximum on day 7 after ICH as compared with that of the sham-operated group. With continuous Brdu injection, the increase was observed on day 14 after ICH, and till day 28, the Brdu-immunoreactive cells in the SVZ decreased to the control level, but some positive cells still persisted in the tissues around the hematoma. CONCLUSION: ICH induces transient and regional increase in the cell proliferation in the ipilateral and contraletral SVZ and tissues around the hematoma, and the proliferating cells in the SVZ may migrate towards the hematoma area.