MMP-9 expression and activity is concurrent with endothelial cell apoptosis in the basilar artery after subarachnoid hemorrhaging in rats.

Subarachnoid hemorrhage refers to one kind of lethal stroke. While several studies have shown the role of matrix metalloproteinase 9 in cerebral tissues and microvasculature after subarachnoid hemorrhage the role of matrix metalloproteinase 9 in large cerebral vasculature is limited, The present study aimed at investigating the relationship between the expression and activity of matrix metalloproteinase 9 and vascular endothelial cell apoptosis in the basilar artery at early-stage post-subarachnoid hemorrhaging in rats. The expression and activity of matrix metalloproteinase 9 in the basilar artery increased at 12 h after subarachnoid hemorrhage and peaked at 24 h. Concurrently, the number of apoptotic cells in the basilar artery increased at 12 h and peaked at 24 h following subarachnoid hemorrhage. Additionally, laminin and cleaved caspase 3 reached to their lowest and highest levels at 24 h after subarachnoid hemorrhage, respectively. Our results suggested that the change in expression and activity of matrix metalloproteinase 9 paralleled that of apoptotic cells in the basilar artery following subarachnoid hemorrhage. Matrix metalloproteinase 9 may be contributing to the injury of the basilar artery after subarachnoid hemorrhage via laminin degradation. Although the underlying mechanisms need to be explored further, our study has shown a potential association of matrix metalloproteinase 9 with injury of the basilar artery and can be associated with early-stage brain injury following subarachnoid hemorrhage.