Relationship between apoptosis and bcl-2 expression after cerebral hemorrhage in rats

Objective To explore the relationship between the apoptosis and bcl 2 expression around the hematoma in intracerebral hemorrhage (ICH). Methods The ICH rat model was established by intracranial injection of Ⅳ collagenase. Brain tissues around the hematoma were collected at 6, 12, and 24 h, and 3 and 7 d after hemorrhage for the preparation of frozen sections for staining. Apoptosis was observed by TUNEL, and bcl 2 expression was observed by immunohistochemistry and in situ hybridization. The relationship between apoptosis and bcl 2 expression was analyzed by image analyzer and statistical methods. Results TUNEL positive cells were found around the hematoma at 6 h after ICH. At the same time, the expression of bcl 2 was low. And then, the TUNEL positive cells increased and reached the peak at 3 d after ICH. Meanwhile, the expression of bcl 2 was still very low. Then the TUNEL positive cells decreased until 7 d after ICH, but the expression of bcl 2 increased. Conclusion Apoptosis can be found around the hematoma after ICH. The decreased expression of bcl 2 is one of the most important step in ICH induced apoptosis.