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

To discuss the relationship between the expression of endothelin receptor A (ETRA) in brain tissue and delayed neurological deficit (DND) after subarachnoid hemorrhage (SAH).

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.

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).

ETRA is expressed distinctly in the brain tissue, and it may play an important role in DND pathogenesis.