Objectives: Cerebral vasospasm has been the dreaded complication of ruptured intracranial aneurysms. Worldwide effort has led to many promising experimental treatments but none was confirmed to be effective in clinical trials. Ecdysterone is an insect steroid hormone. Our previous study showed that ecdysterone might prevent cerebral vasospasm in vitro. Even after all these works, rare attempts have been made to test the effect of ecdysterone on vascular adventitial fibroblast (VAF) proliferation, a process known to play an important role in various pathogenic vascular conditions. Thus, we tested the hypothesis that ecdysterone could affect VAF characteristics and have an effect on SAH induced cerebral vasospasm.
Methods: OxyHb of 100 microM was used in the in vitro study to mimic the clinical situation. The effect of OxyHb on the cell proliferation and migration of cultured aortic smooth muscle cells was investigated. In the in vivo study, 20 rabbits were equally divided into four groups: control group, SAH group, SAH/nimodipine group and SAH/ecdysterone group. Changes in neurological function and cerebral angiograms were observed after SAH.
Results: OxyHb increased the proliferation of vascular adventitial fibroblasts at 24 hours. Ecdysterone co-treatment was apparently similar to the suppression of proliferation. Cell cycle analysis indicated that ecdysterone inhibited the progression of vascular adventitial fibroblasts from G1 to S. The results of the migration assay showed that 100 microM OxyHb obviously prompted vascular adventitial fibroblast migration and that ecdysterone would attenuate this effect. In the SAH/nimodipine and SAH/ecdysterone groups, neurological deficit, cerebral vasospasm and structural changes in basilar artery were alleviated with nimodipine or ecdysterone treatment.
Conclusion: Ecdysterone could affect vascular adventitial fibroblast characteristics and attenuate vasospasm after SAH.