Nrf2 knockout and brain injury following subarachnoid hemorrhage in mice / 医学研究生学报

ABSTRACT

Objective Subarachnoid hemorrhage ( SAH) is a devastating disease with a high mortality.This study was to in-vestigate the effect of Nrf2 on secondary brain injury following SAH and its action mechanism in mice. Methods SAH models were established in wild-type ( WT) and Nrf2 knockout ( KO) ICR male mice by injecting fresh blood drawn from the femoral artery into the pre-chiasmatic cistern.The animals were divided into four groups, WT sham, WT SAH, KO sham, and KO SAH.At 24 hours after modeling, the expression levels of malondialdehyde ( MDA) , GSH/GSSG, TNF-αand IL-1β, the volume of brain water, and content of Evans blue were measured, the activity scores obtained, and cerebral vasospasm of the anterior and middle cerebral arteries ( ACA and MCA) detected. Results At 24 hours, the expressions of MDA, TNF-α, and IL-1βwere (3.299 ±0.335), (1.187 ± 0.436), and (59.330 ±21.787) mg/g in the WT sham group, (4.339 ±0.328), (2.432 ±0.434), and (121.584 ±21.675) mg/g in the WT SAH group, (3.488 ±0.634), (1.170 ±0.312), and (58.497 ±15.608) mg/g in the KO sham group, and (5.335 ±0.499), (3.132 ±0.548), and (171.117 ±50.479) mg/g in the KO SAH group, markedly increased in the SAH groups as compared with the sham controls (P<0.05), while the GSH/GSSG levels were significantly higher in the former two groups than in the latter (0.553 ±0.100 and 0.375 ±0.068 vs 0.714 ±0.091, 0.761 ±0.114, P<0.01).The contents of brain water and Evans blue were (0.784 ±0.005) and (7.055 ±1.046) μg/g in the WT sham group, (0.808 ±0.004) and (7.230 ±1.192) μg/g in the WT SAH group, (0.784 ±0.004) and (9.620 ±1.290) μg/g in the KO sham group, and (0.819 ±0.004) and (11.628 ±1.040)μg/g in the KO SAH group, remarkably increased in the SAH groups in comparison with the sham groups (P<0.05).The apoptosis rate 8.916 and 82.100 ±6.870 vs 70.833 ±8.750 and 51.767 ±13.006), ACA radius/wall thickness value (13.885 ±3.360 and 14.212 ±3.2545 vs 8.024 ±2.780 and 6.861 ±2.702), MCA radius/wall thickness value (18.648 ±2.893 and 19.435 ±2.775 vs 6.337 ±3.993 and 5.107 ±3.805), and activity score (2.733 ±0.450 and 2.767 ±0.430 vs 1.967 ±0.928 and 1.433 ±0.679) (all P<0.01). Conclusion Nrf2 knockout increases oxidative stress and inflammatory reaction following SAH and consequently aggravates secondary brain injury.Nrf2 has a protective effect against SAH-induced brain injury.