Nrf2调控AIM2炎症小体在大鼠脑缺血再灌注 损伤中的作用

目的 探讨核因子E2相关因子2（Nrf2）对脑缺血再灌注损伤的影响及对黑色素瘤缺乏因子2（AIM2）炎症 小体的调控作用。方法 将108只雄性SD大鼠按随机数字表法分为假手术组（Sham组）、脑缺血再灌注模型组（I/R 组）、Nrf2抑制剂鸦胆子苦醇（Bru）干预组（Bru组），每组再按随机数字表法进一步分为脑缺血再灌注后8、24、72 h组， 共9组，每组12只。I/R组和Bru组采用线栓法建立大脑中动脉栓塞（MCAO）模型。于相应时间点对各组行神经功能 缺损评分；采用2，3，5-氯化三苯基四氮唑（TTC）染色测定脑梗死面积；HE染色检测脑组织病理损伤；荧光定量PCR 法检测缺血侧脑组织中AIM2 mRNA表达；Western blot法检测缺血区脑组织中AIM2、Nrf2蛋白的表达；酶联免疫吸 附试验法检测缺血区脑组织中凋亡相关斑点样蛋白（ASC）、半胱氨酸蛋白酶（Caspase）-1、白细胞介素（IL）-1β和IL-18 的表达。结果 与Sham组比较，I/R组各时间点神经功能缺损评分升高，脑组织病理损伤显著加重，AIM2 mRNA以 及Nrf2、AIM2、ASC、Caspase-1、IL-1β、IL-18蛋白表达水平升高（P＜0.05）。与I/R组比较，Bru组各时间点神经功能 缺损评分升高，脑组织病理损伤更重，Nrf2蛋白表达水平降低，AIM2 mRNA和蛋白，ASC、Caspase-1、IL-1β、IL-18蛋 白表达水平升高（P＜0.05）。结论 Nrf2在脑缺血再灌注损伤中具有内源性神经保护作用，其机制可能与Nrf2可负 性调控AIM2炎症小体，减少炎性细胞因子的释放有关。

The role of Nrf2 in regulating AIM2 inflammation in cerebral ischemia reperfusion injury in rats

Objective To investigate the effect of nuclear factor E2 related factor 2 (Nrf2) on cerebral ischemiareperfusion injury and the regulation of melanoma deficiency factor 2 (AIM2) inflammatory bodies. Methods A total of 108 male SD rats were divided into the sham group, the cerebral ischemia-reperfusion group (I/R group) and the Brucitol intervention group (Bru group) according to random number table. Each group was further divided into 3 groups at 8 h, 24 h and 72 h after cerebral ischemia-reperfusion with 12 rats in each group according to random number table. Middle cerebral artery occlusion (MCAO) model was established by using the the Longa method in the I/R group and the Bru group. The neurological deficits were scored at the corresponding time points. The area of cerebral infarction was detected by 2, 3, 5- triphenyltetrazolium chloride (TTC). The brain tissues injury was detected by HE staining. qPCR was used to detect expression of AIM2 mRNA in brain tissue on the ischemic side. Western blot assay was used to detect the expression levels of AIM2 and Nrf2 proteins in ischemic brain tissue. The expressions of apoptosis-related speck-like protein (ASC), Caspase- 1, interleukin (IL) -1β and IL-18 in ischemic brain tissue were detected by ELISA. Results Compared with the sham group, neurological deficit score at each time point in the I/R group was increased (P＜0.05), and pathological injury of brain tissue was significantly aggravated. AIM2 mRNA, the protein expression levels of Nrf2, AIM2, ASC, Caspase-1, IL-1β and IL-18 were increased in the I/R group (P＜0.05). Compared with the I/R group, the neurological deficit score was higher at each time point in the Bru group, and the cerebral infarction area was larger (P＜0.05). There were more severe pathological damage of brain tissue, lower Nrf2 protein expression level. AIM2 mRNA and protein was higher, and cerebral infarction area was higher (P＜0.05), the protein expression levels of ASC, Caspase-1, IL-1β and IL-18 increased (P＜ 0.05). Conclusion Nrf2 plays an endogenous neuroprotective role in cerebral ischemia-reperfusion injury, and the mechanism may be related to Nrf2 negatively regulating AIM2 inflammasome and reducing the release of pro-inflammatory cytokines.