蛛网膜下腔出血兔脑组织内皮素受体A表达的研究

An experimental study of endothelin receptor A expression in brain tissue after subarachnoid hemorrhage in rabbits

目的 探讨蛛网膜下腔出血(SAH)后脑组织内皮素受体A(ETRA)的表达与延迟性神经功能障碍(DND)之间的关系.方法 将31只日本大耳白兔随机分组:SAH组15只,盐水对照组10只,穿刺对照组与正常对照组各3只,SAH组和盐水对照组再均分为制模后1 h、3 d、5 d、7 d、10 d共5个亚组,采用枕大池二次注血法制备兔SAH模型.按各时间点将兔进行灌注,处死后取其被血液浸泡的基底动脉中段脑干组织制成切片,进行苏木素一伊红(HE)染色及ETRA免疫组化染色;光镜下观察延髓组织病理学变化,采用阳性细胞计数法对ETRA进行半定量分析.结果 穿刺对照组、正常对照组兔脑组织中神经元细胞和胶质细胞胞质内均有少量ETRA表达[(10.6±3.9)个/视野,(10.0±2.8)个/视野];盐水对照组内有个别细胞表达ETRA,对各亚组间阳性细胞计数进行方差分析,结果显示差异无统计学意义[最低(12.3±2.1)个/视野,最高(13.3±2.6)个/视野,P>0.05];SAH组制模后1 h ETRA表达的阳性细胞计数有轻微升高C(20.1>3.5)个/视野],3 d表达最强烈[(48.8±6.7)个/视野],5、7、10 d呈缓慢下降的趋势[分别为(23.1±2.9)、(22.5±4.2)、(19.1±2.8)个/视野],方差分析结果显示差异有统计学意义(P<0.05),且制模后各时间点ETRA阳性细胞数明显高于盐水对照组(P均<0.05).结论 SAH后兔脑组织ETRA呈高度表达;ETRA可能在DND的发病机制中起到重要的作用.

Objective To discuss the relationship between the expression of endothelin receptor A (ETRA) in brain tissue and delayed neurological deficit (DND) after subarachnoid hemorrhage (SAH). Methods Thirty-one Japanese rabbits were divided into SAH group (n=15), saline group (n= 10), puncture group (n=3), normal control group (n= 3) randomly, and they subdivided into 1 hour, 3 days, 5 days, 7 days, 10 days subgroups in both SAH group and saline group. The SAH model was successfully reproduced by intracisternal injection of autologous arterial blood twice. When the animals were sacrificed by perfusion, brain stems were harvested and prepared for immunohistochemical staining and hematoxylin and eosin (HE) staining. The pathological changes in the brain tissue were observed with light microscope. Then positive-cell counting was used to semi-quantitative analysis. Results The expression of ETRA was not detected nearly in neurons or gliocyte either in puncture group (10. 6± 3. 9) or in normal group (10. 0± 2.8), while it was detected in some cells in saline group. But no significant difference was showed among the subgroups in saline group (12.3±2.1 lowest vs. 13.3±2. 6 highest, P>0. 05) by variance analysis. The expression of ETRA in SAH group was slightly stronger after 1 hour (20. 1 ± 3. 5), peaked at 3 days (48. 8±6. 7), and became weak gradually after 5 days. The ETRA positive cells at 5 days, 7 days, and 10 days were 23. 1 ± 2.9, 22.5 ± 4.2 and 19.1 ± 2.8 respectively. There were significant differences among the values at different time points (P<0.05) in SAH group, and the positive cells of ETRA were obviously increased in number in SAH group at all time points compared with saline group (all P<0. 05). Conclusion ETRA is expresseddistinctly in the brain tissue, and it may play an important role in DND pathogenesis.