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目的观察选择性激动黑皮质素4型受体(MC4R)对脓毒症致急性肝损伤大鼠的影响。方法 64只雄性SD大鼠随机分假手术组(假手术后用PBS处理)、盲肠结扎穿孔(CLP)组(采用CLP建立脓毒症模型)、Ro27-3225处理组(CLP后用Ro27-3225处理)和Ro27-3225假手术对照组(假手术后用Ro27-3225处理),每组16只(10只大鼠观察术后一般状态和72 h生存率,另外6只大鼠于术后24 h采集血液及肝组织标本)。各组分别于术后30 min腹腔注射PBS或Ro27-3225(180μg/kg),术后24 h测定大鼠心率(HR)及平均动脉压(MAP)、大鼠血清中天门冬氨酸氨基转移酶(AST)和丙氨酸氨基转移酶(ALT)水平。动物处死后,HE染色观察肝组织病变,反转录PCR检测肝组织中Toll样受体4(TLR4)、高迁移率族蛋白1(HMGB1)和caspase-3 mRNA水平,免疫组织化学染色检测肝细胞中核因子κB(NF-κB)p65的表达,并分析NF-κB p65核阳性率。结果与假手术组相比,CLP组大鼠72 h生存率和MAP降低,血清中AST和ALT水平明显升高,肝索排列紊乱,肝细胞水肿,有明显炎性细胞浸润,肝组织中TLR4、HMGB1和caspase-3 mRNA水平明显升高,肝细胞中NF-κB p65核阳性率明显升高。与CLP组相比,Ro27-3225处理组大鼠72 h生存率和MAP明显升高,血清中AST和ALT水平明显降低,肝组织结构损伤明显减轻,肝组织中TLR4、HMGB1和caspase-3 mRNA水平降低,肝细胞中NF-κB p65核阳性率明显降低。结论脓毒症能引起肝损伤,选择性激动MC4R可能通过抑制HMGB1/TLR4/NF-κB信号途径,减轻炎症反应,降低脓毒症引起的肝损伤。
Objective To investigate the effect of selective activation of melanocortin 4 receptor (MC4R) on acute liver injury induced by sepsis in rats. Methods Sixty-four male Sprague-Dawley rats were randomly divided into sham operation group (PBS treated with sham operation), cecal ligation and puncture (CLP group established sepsis model), Ro27-3225 treatment group (CLP treated with Ro27-3225 And Ro27-3225 sham operation control group (Ro27-3225 after sham operation), 16 rats in each group (10 rats were observed postoperative general condition and 72 h survival rate, the other 6 rats after operation 24 h collecting blood and liver tissue specimens). The rats were injected intraperitoneally with PBS or Ro27-3225 (180μg / kg) at 30 min after operation and the heart rate (HR) and mean arterial pressure (MAP) were measured at 24 h after operation. The aspartate aminotransferase Enzyme (AST) and alanine aminotransferase (ALT) levels. After the animals were sacrificed, the pathological changes of liver were observed by HE staining. The expression of TLR4, HMGB1 and caspase-3 mRNA in liver tissues were detected by reverse transcription polymerase chain reaction (RT-PCR) Cell nuclear factor kappa B (NF-κB) p65 expression, and analysis of NF-κB p65 nuclear positive rate. Results Compared with the sham operation group, the survival rate and MAP in 72 h group were significantly decreased, the levels of AST and ALT in serum were significantly increased, the hepatic cord was disordered, the hepatocyte edema was obvious, the infiltration of TLR4 , HMGB1 and caspase-3 mRNA levels were significantly increased, and the positive rate of nuclear NF-κB p65 in hepatocytes was significantly increased. Compared with the CLP group, the survival rate and the MAP of 72 h group were significantly increased in Ro27-3225-treated group, the levels of AST and ALT in serum were significantly decreased, and the structural damage of liver tissue was significantly reduced. The expressions of TLR4, HMGB1 and caspase-3 mRNA The level of NF-κB p65 nuclear positive rate was significantly decreased in hepatocytes. Conclusion Sepsis can cause liver injury. Selective activation of MC4R may reduce the inflammatory response and reduce the hepatic injury induced by sepsis by inhibiting the signaling pathway of HMGB1 / TLR4 / NF-κB.