右美托咪定对小鼠视网膜缺血再灌注损伤的保护机制

Protection mechanism of dexmedetomidine against retinal ischemia-reperfusion injury in mice

目的研究右美托咪定对小鼠视网膜缺血再灌注损伤的保护作用机制。方法选取8周龄C57BL/6雄性小鼠48只,按照体重随机分为3组:假手术组、模型组和实验组,每组16只。制备小鼠视网膜缺血再灌注损伤(RIRI)模型。在缺血前15 min和再灌注前5 min,实验组小鼠分别腹腔注射右美托咪定25μg·kg^(-1),假手术组和模型组腹腔注射同等剂量的0.9%Na Cl。在模型建立成功后,于再灌注24 h处死并取材。取小鼠视网膜组织匀浆液,用四唑盐试剂(WST-1)法检测超氧化物歧化酶(SOD),用TBA法检测丙二醛(MDA),用比色法测定谷胱甘肽过氧化物酶(GSH-PX),用酶联免疫吸附法检测肿瘤坏死因子α(TNF-α)、白细胞介素-6(IL-6)、1-甲基环丙烯(1-MCP)及IL-10水平。结果与假手术组比较,模型组小鼠视网膜组织中SOD为(45.47±8.16)U·mg^(-1)、GSH-PX为(264.64±27.31)U·mg^(-1),均明显降低;而MDA为(1.56±0.41)nmol·mg^(-1)、TNF-α为(2.67±0.23)ng·mL^(-1)、IL-6为(2.84±0.34)ng·mL^(-1)、MCP-1为(0.68±0.06)ng·mL^(-1)和IL-10为(0.21±0.02)ng·mL^(-1),均明显升高,差异有统计学意义(均P<0.05)。与模型组比较,实验组小鼠视网膜组织中SOD为(71.05±9.34)U·mg^(-1)、GSH-PX为(382.20±31.56)U·mg^(-1)、IL-10为(0.44±0.07)ng·mL^(-1),均明显降低;而MDA为(1.02±0.23)nmol·mg^(-1)、TNF-α为(1.53±0.20)ng·mL^(-1)、IL-6为(1.64±0.07)ng·mL^(-1)、MCP-1为(0.41±0.07)ng·mL^(-1),均明显降低,差异有统计学意义(P<0.05)。结论右美托咪定可以改善视网膜缺血再灌注损伤,其机制与抑制氧自由基所致的脂质过氧化损伤和抑制炎症因子的分泌有关。

Objective To investigate the protection mechanism of dexmedetomidine against retinal ischemia-reperfusion injury（RIRI） in mice. Methods Forty-eight male C57BL/6 mice born 8 weeks were randomly into sham group,model group and experimental group. Each group had 16 mice. Mice model of RIRI were prepared. Before modeling15 min,dexmedetomidine 25 μg · L^-1was injected into the abdominal cavity in experimental group,and the same dose of 0. 9% normal saline was injected into the abdominal cavity in sham group and model group.The RIRI model was established successfully then these mice were killed after reperfusion 24 h. The superoxide dismutase（SOD） was detected by WST-1 method,the malondialdehyde（MDA） was detected by TBAmethod,and the glutathione peroxidase（GSH-PX） was determined by colorimetry. The tumor necrosis factor alpha（TNF-α）,interleukin-6（IL-6）,1-methylcyclopropene（MCP-1） and interleukin-10（IL-10） were detected by ELISA. Results Compared with the sham group,the levels of SOD（45. 47 ± 8. 16） U · mg^-1and GSH-PX（264. 64 ± 27. 31） U·mg^-1in the retinal tissue of the model group were decreased significantly（P〈0. 05）. While MDA（1. 56 ± 0. 41） nmol·mg^-1,TNF-α（2. 67 ± 0. 23） ng·mL^-1,IL-6（2. 84 ± 0. 34） ng·mL^-1,MCP-1（0. 68 ± 0. 06） ng ·mL^-1and IL-10（0. 21 ± 0. 02） ng · mL^-1in the retinal tissue of the model group were decreased significantly（P〈0. 05）. Compared with the model group,the levels of SOD（71. 05 ± 9. 34） U · mg^-1,GSH-PX（382. 20 ± 31. 56） U·mg^-1and IL-10（0. 44 ± 0. 07） ng·mL^-1in the retina tissue of the experimental group were decreased significantly（P〈0. 05）. while MDA（1. 02 ± 0. 23） nmol · mg^-1,TNF-α（1. 53 ± 0. 20）ng·mL^-1,IL-6（1. 6 ± 0. 07） ng · mL^-1and MCP-1（0. 41 ± 0. 07） ng · mL^-1of the experimental group experimental group were decreased significantly（P〈0. 05）. Conclusion Dexmedetomidine can significantly reduce RIRI,the mechanism may be related to inhibit oxygen free radical-induced lipid peroxidation injury and inhibit the secretion of inflammatory cytokines.