Changes in expression of tumor necrosis factor-α in basilar artery after subarachnoid hemorrhage

Objective To investigate the possible role of tumor necrosis factor-α(TNF-α) in the pathogenesis of cerebral vasospasm in a rat double-hemorrhage model.Methods Subarachnoid hemorrhage(SAH) was produced according to the double-hemorrhage method.Hematoxylin-eosin(HE) staining was used to assess vasospasm in the basilar artery and the expression of TNF-α after SAH was examined by immunohistochemical staining,enzyme-linked immunosorbent assay(ELISA) and reverse transcription polymerase chain reaction(RT-PCR).Results After SAH,the basilar artery gradually showed vasospasm from 1 d,reached the peak in 5 d to 7 d and resumed the normal condition in 14 d.The number of TNF-α positive endothelial cells and the level of TNF-α protein started to increase in 1 d,reached its peak in 7 d,and remained at a relative high level in 14 d.The expression level of TNF-α mRNA in the spastic basilar artery was highest in 7 d and remained at a relative high level in 14 d.Conclusion The basilar artery shows obvious vasospasm after SAH.The pattern of maximum TNF-α level fits remarkably well with the time course of vasospasm,which may indicate that TNF-α leads to the development of cerebral vasospasm after SAH.