Experimental Study The Role Of Autophagy In Early Brain Injury After Subarachnoid Hemorrhage In Rats

Objective: To investigate the changes of expression of LC3 and Beclin-1 in cerebral cortex after SAH in rats and to explore the role of autophay in EBI after SAH.Methods: A total of 30 male S-D rats were randomly divided into control group, SAH6h group, SAH12h group, SAH24h group and SAH48h group. The pre-chiasmatic injection technic was used to induce SAH. Temporal-basal cortex was taken for analysis. LC3 and Beclin-1, two biomarkers of autophagy, were measured by western blot and immunohistochemistry.Results: LC3 and Beclin-1 were low expression in control group; Compared with control group LC3 in cerebral cortex was significantly increased at 6h (P<0.05) following SAH, it was expression peaked at 24h ( P<0.01) and approximate 11 times than in control group, it still had siginificant at 48h( P<0.01). At the same time Beclin-1 was also significantly increased at 6h (P<0.05) and expression peaked at 24h (raised approximate 2 times, P<0.01), but at 48h there was no significant (P>0.05).Conclusions: Autophagy pathway was activated in the brain after SAH and autophagy activity was the strongest at 24h. It prompted that autophagy may play an important role in EBI after SAH. Objective: To investigate the changes of neurologic scoring, brain water content and BBB permeability when use autophagy activator and inhibitor in rats and further study the potential role of autophagy in EBI after SAH. Methods: 60 health male S-D rats were assigned randomly into following groups: control group, SAH group, SAH+vehicle group, SAH+RAP group and SAH+3-MA group. Western blot was performed to detect the changes of LC3 and beclin-1. At 24h after SAH,we investigate the changes of neurologic scoring, brain water content and BBB permeability in each group.Results: Compared with control group, LC3 and Beclin-1 in cerebral cortex were significantly increased (P<0.01) following SAH, at the same time rats had significant brain water content (P<0.01) and BBB permeability dysfunction(P<0.01); compared with SAH+vehicle group, the level of LC3 and Beclin-1 were markedly up-regulated (P<0.05), the mean value of brain water content was decreased(P<0.01), BBB permeability was getting better(P<0.01, both Evans blue method and IgG method), at the same time rats showed better performance(P<0.01) in SAH+RAP group. But in SAH+3-MA group LC3 and Beclin-1 expression were significantly decreased(compared with SAH+vehicle group, P<0.01), BBB permeability was getting worse(compared with SAH+vehicle group, P<0.05, IgG method) and the clinical behavior was getting worse(compared with SAH+vehicle group, P<0.05).Conclusions: When use RAP intervene autophagy, LC3 and Beclin-1 expression were significantly inceased that prompting autophagy activity was much stronger, at the same time ameliorated the brain edema, BBB permeability and clinical behavior which showed strengthen autophagy can alleviate EBI after SAH. Conversely 3-MA can aggravate EBI.