右美托嘧啶对大鼠肾脏缺血再灌注后炎性反应的保护作用

Protective effect of dexmedetomidine on inflammation induced by renal ischemia and reperfusion injury in rats

目的 探讨右美托嘧啶对大鼠肾脏缺血再灌注后炎性反应的保护作用及其机制.方法 将24只大鼠随机分为3组,每组8只.假手术组：游离双侧肾脏,切除右肾后缝合腹壁;缺血再灌注组：切除右肾,夹闭左肾动、静脉45 min后再灌注24 h,余同假手术组.右美托嘧啶组：夹闭左肾动、静脉前30 min,腹腔注射右美托嘧啶（100 μg/kg）,余同缺血再灌注组.再灌注24 h后,检测各组大鼠血清肌酐、尿素氮,苏木素-伊红（HE）染色观察肾组织病理变化,实时荧光定量聚合酶链反应（FQ-PCR）检测肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）、细胞间黏附分子（ICAM-1）的水平,Western blot检测Toll样受体4（TLR4）和核因子-κB （NF-κB）的表达.结果 在假手术组、缺血再灌注组和右美托嘧啶组中,血清肌酐（μmol/L）分别为17.55±1.02、138.49±6.20、81.98 ±4.24,血清尿素氮（mmol/L）分别为7.00±2.06、27.38±4.37、13.75±3.54,假手术组的血清肌酐、尿素氮水平明显比缺血再灌注组和右美托嘧啶组低（P＜0.05）,而缺血再灌注组的血清肌酐、尿素氮水平显著高于右美托嘧啶组（P＜0.05）.HE染色可见缺血再灌注组的肾小管上皮细胞明显变性坏死,有大量炎性细胞浸润,而右美托嘧啶可以明显减轻损伤.与假手术组比较,缺血再灌注组和右美托嘧啶组TNF-α、IL-1β、ICAM-1、TLR4、NF-κB水平均显著升高,而右美托嘧啶组的上述指标明显低于缺血再灌注组.结论 右美托嘧啶可以减轻大鼠肾脏缺血再灌注损伤导致的炎性反应,其机制可能与抑制TLR4/NF-κB通路的表达有关.

Objective To investigate the effect of dexmedetomidine on inflammation induced by renal ischemia and reperfusion injury （IRI） in rats.Methods Twenty SD rats were randomly divided into three groups：sham operated group,IRI group and dexmedetomidine group.Each group had 8 rats.In sham operated group,the right kidneys of rats were excised.In IRI group,with no wound vascular clamp,left renal arteries and veins of rats were clamped for 45 min,then vascular clamp was opened and the rats were subjected to repeffusion.In Dexmedetomidine groups,operation steps were the same as the IRI group,but at 30 min before ischemia,dexmedetomidine was given by intraperitoneal injection （100 μg/kg）.The parameters [blood urea nitrogen （BUN） and ereatine （Cr）] for renal function were determined by auto-biochemieal analyzer.The expression levels of tumor necrosis factor （TNF）-α,interleukin （IL）-1 β and intercellular adhesion molecule-1 （ICAM-1） were measured by real-time fluorescent quantitative polymerase chain reaction （FQ-PCR） and the changes of renal tissue were examined by a microscope.The expression of Toll-like receptor4 （TLR4） and nuclear factor-κB （NF-κB） was detected by Western blotting.Results In sham group,IRI group and dexmedetomidine group,Cr levels （μmol/L） were 17.55 ± 1.02,138.49 ± 6.20 and 81.98 ±4.24,respectively,and BUN levels （mmol/L） were 7.00 ±2.06,27.38 ±4.37 and 13.75 ±3.54,respectively.Cr and BUN levels in sham operated group were obviously lower than in IRI group and dexmedetomidine group,and those in IRI group were significantly higher than in dexmedetomidine group.As compared with sham operated group,TNF-α,IL-1β,ICAM-1,TLR4 and NF-κB were significantly increased in IRI group and dexmedetomidine group.However,these targets in dexmedetomidine group were significantly decreased as compared with those in IRI group.Conclusion Dexmedetomidine can alleviate inflammation induced by renal IRI probably by inhibiting the expression of TLR4/NF-κB signaling pathway.