HO-1在体外循环中的肾保护作用及其机制初探

Preliminary Investigate of Protection of Renal by HO-1 during Extracorperation and Its Molecular Mechanism

目的探讨血红素加氧酶-1(HO-1)在体外循环猪模型中对肾微循环的保护作用及其分子机制。方法按常规方法以体重15 kg左右约克猪建立体外循环模型,体外循环时间共为3 h,其中主动脉阻断时间为1 h。共分为4个实验组:组1为单纯体外循环组;组2为单纯血红素加氧酶-1抑制剂组,仅麻醉3 h,不进行体外循环;组3为血红素加氧酶-1诱导组,在进行体外循环之前用高铁血红素预处理诱导血红素加氧酶-1的表达;组4为血红素加氧酶-1抑制组,除与组1相同之处理外,还加用血红素加氧酶-1的抑制剂锡卟啉Ⅺ进行处理。各组于术前至术后1 h检测尿NAG/Cr,并对术后1 h之肾组织进行光镜和电镜检查,了解肾组织损害情况。运用RT-PCR及免疫组化方法检测TNF-α的mRNA和蛋白质在各组动物肾组织中的表达情况,并对免疫组化染色结果进行定量分析和统计学处理。另外用间接法测定各组HO-1活性。结果与单纯体外循环组相比,HO-1诱导组肾功能受损较轻,光镜下与电镜下肾损害均有明显减轻,同时血红素加氧酶的活性和表达明显增高,而TNF-α的表达则受到抑制;加用HO-1抑制剂后,HO-1的活性下降,其肾保护效应被取消,而TNFα-的表达更为显著,且肾损害更为严重;单纯HO-1抑制剂而未进行体外循环组中未见肾损害情况。结论HO-1对体外循环后早期的肾功能具有保护作用,其机制可能与抑制肾组织局部TNF-α的表达有关,HO-1诱导可能成为一种新的有效的体外循环肾保护措施。

Objective Examine the role of heine oxygenase-l（HO-1） on protection of renal micro circulation during cardiopulmonary bypass porcine models and its molecular mechanism. Methods The extracorporeal circulation model was created routinely using pigs weighing around 15 kg. Total CPB time for each animal was 3 hours,including one hour for aorto clamping. Four study groups were setted.group 1 simply accepted CPB for 3 hours; animals in group 2 received HO- 1 inhibitors without CPB ; group 3 was pretreated with hemin to induce HO-1 before CPB; while HO-1 inhibitors was employed in group 4 additionally to the treatment identical with group 1. Urine NAG/Cr was measured preoperatively. The specimen of the kidney were taken at one hour postoperatively. Lesions in kidney constitutions were detected by pathological examination and electron microscope. The mRNA and protein expressions of TNF-α were inspected by RT-PCR and immunohistochemistry,while HO-1 activity was determined simultaneously. Results Compared with group 1, renal injuries were much more relieved in group 3 while observing under microscope and electron microscope;at the same time, their NAG/Cr levels were also lower. Meanwhile, the activity of HO-1 were much higher in group 3 than in group 1, but the expression of TNF-α was lower. In group 4, HO-1 activity was inhibited, while levels of renal injury, and TNF-α expression were even higher than that in group 1. There was no damage in group 2. Concision HO-1 may play an important role on renal micro circulation protection during CPB. The mechanism of which may be related to inhibition of TNF-α expression in kidney. Induction of HO-1 may be used as a novel effective way for renal protective during cardiopulmonary bypass.