SLC7A11在右美托咪定预处理减轻小鼠肠缺血再灌注损伤引起铁死亡中的保护作用

目的：评价SLC7A11在右美托咪定预处理减轻小鼠肠缺血再灌注损伤引起铁死亡中的作用。方法：24只雄性健康SPF级C57BL/6J小鼠，8周龄，体质量22～25 g，随机数表法分成4组：假手术组（S组）、肠缺血再灌注组（II/R组）、右美托咪定组（DEX组）、右美托咪定+SLC7A11抑制剂组（DIKE组），每组6只。夹闭肠系膜上动脉（superior mesenteric artery, SMA）45 min，再灌注30 min建立小鼠肠缺血再灌注损伤模型。DEX组和DIKE组夹闭SMA前30 min腹腔注射25 μg/kg DEX，S组和II/R组腹腔注射等量生理盐水；DIKE组缺血前90 min腹腔注射SLC7A11抑制剂Imidazole ketone erastin 50 mg/kg。再灌注30 min时处死小鼠，距回盲瓣约5 cm处取小肠组织，HE染色光镜下观察肠黏膜病理改变并行Chiu评分，比色法测定小肠组织Fe2+、丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性，微板法测定谷胱甘肽（glutathione, GSH）含量，免疫印迹法检测小鼠小肠组织SLC7A11、谷胱甘肽过氧化物酶4（glutathione peroxidase 4, GPX4）的表达。结果： 与S组比较，其余3组小肠组织Chiu评分、Fe2+和MDA含量升高，GSH含量降低，SOD活性下降，SLC7A11、GPX4表达下调（P<0.05）；给予右美托咪定后明显降低小肠组织Chiu评分、Fe2+和MDA含量，增加SOD活性和GSH含量，SLC7A11、GPX4表达上调（P<0.05）；腹腔注射SLC7A11抑制剂后得到的结果相反。结论：SLC7A11的激活在右美托咪定减轻小鼠肠缺血再灌注损伤引起的铁死亡中发挥保护作用。

Effect of SLC7A11 in dexmedetomidine pretreatment induced reduction of ferroptosis caused by intestinal ischemia-reperfusion injury in mice

AIM: To evaluate the effect of SLC7A11 in dexmedetomidine pretreatment induced reduction of ferroptosis caused by intestinal ischemia-reperfusion (II/R) injury in mice. METHODS: Twenty-four healthy meal SPF C57BL/6J mice, aged 8 weeks, weighing 22-25 g, were randomly divided into Sham operation group (S group), intestinal I/R group (II/R group), dexmedetomidine group (DEX group) and dexmedetomidine plus SLC7A11 inhibitior group (DIKE group), with 6 mice in each group. Intestinal ischemia was induced by occluding the superior mesenteric artery for 45 min followed by 30 min of reperfusion to establish the model of II/R injury. In DEX and DIKE groups, Dexmedetomidine 25 μg/kg was intraperitoneally injected at 30 min before clamping the superior mesenteric artery. The same amount of normal saline was injected in the S group and the II/R group. In DIKE group, SLC7A11 inhibitior Imidazole ketone erastin 50 mg/kg was intraperitoneally injected at 90 min before ischemia. Mice were sacrificed 30 min after reperfusion, and small intestinal tissues in length 5 cm away from the ileocecal valvum were obtained for microscopic examination of pathological changes of intestinal mucosa and for determination of contents of Fe2+ and malondialdehyde (MDA) and superoxide dismutase (SOD) activity (by colometry), reduced glutathione (GSH) content (by microplate method), and expression of SLC7A11, glutathione peroxidase 4 (by Western blot). Intestinal damage was assessed and scored according to Chiu. RESULTS: Compared with group S, Chiu's score, Fe2+ and MDA contents were significantly increased, the SOD activity and GSH content were decreased, and the expression of SLC7A11 and GPX4 was down-regulated in the other 3 groups (P<0.05). Intraperitoneal injection of dexmedetomidine significantly decreased Chiu's score, Fe2+ and MDA contents, increased SOD activity and GSH content, and upregulated SLC7A11 and GPX4 expression (P<0.05). Intraperitoneal injection of the SLC7A11 inhibitor produced the opposite result. CONCLUSION: Dexmedetomidine can protect intestine tissue from ischemia-reperfusion injury, which maybe correlates with activating SLC7A11 and inhibiting ferroptosis.