Assessement of smooth muscle viability in the spastic cerebral arteries during chronic vasospasm

观察蛛网膜下腔出血（SAH）后脑动脉肌膜通透性的变化。用亲水性（溴化乙锭：EB）和亲脂性（Hoechst 33342：H33342）DNA结合染料双染法检测平滑肌细胞（SMC）膜的通透性。用紫外荧光显微镜和紫外激光共聚焦显微镜进行定量观察。用电泳和TUNEL法检测细胞凋亡的发生。正常动脉平滑肌细胞核H_（33342）染色，EB染色阴性。SAH后7天痉挛动脉平滑肌细胞核45（SY ±）。[)19结果显示，在2 ~ 4周内，图尼卡内层SMC的EB阳性细胞数减少（13 ± 0.9%），而在2 ~ 4周内，SMC的EB阳性细胞数减少（13 ± 0.9%）。[)5.2%和5.0（±）SY. [)2.1%）与痉挛改善平行。电镜和光镜观察显示SMC胞质密度增加，细胞外间隙增宽。坏死不明显。两种方法均未检测到细胞凋亡。这些结果表明，在慢性血管痉挛的过程中发生的肌膜通透性增加，并建议其密切相关的发病机制。

Alteration of sarcolemmal permeability was evaluated in the cerebral artery after subarachnoid hemorrhage (SAH). Significance of membrane dysfunction in the pathogenesis of chronic spasm and contribution of apoptosis were investigated in a canine model.Permeability of the smooth muscle cell (SMC) membrane was assessed by double staining with a hydrophilic (ethidium bromide : EB) and a lipophilic (Hoechst 33342 : H33342) DNA-binding dye. Quantitative observations were made with a UV-fluorescence microscope and a UV-laser confocal microscope. Occurrence of apoptosis was studied using electrophoresis and TUNEL method. In the normal arteries, nuclel of SMC were stained with H33342 but not with EB.In the spastic arteries obtained seven days after SAH,45(]SY.+-。[)19% of SMC in the inner layr of the tunica media were stained with EB.The incidence of EB-positive cells decreased in two to four weeks (13(]SY.+-。[)5.2% and 5.0(]SY.+-.[)2.1% respectively) in parallel with amelioration of spasm. Electron and light microscopic observations revealed increased density of SMC cytoplasm with widening of the extracellular space. Necrosis was not evident. Apoptosis was not detected by the two methods. These results demonstrated that an augmentation in sarcolemmal permeability takes place during the course of chronic vasospasm, and suggest its close correlation to pathogenesis.