奥曲肽对小鼠肾脏缺血再灌注损伤的保护作用

Protective effects of octreotide on renal ischemia - reperfusion injury

目的探讨奥曲肽预处理对小鼠肾脏缺血再灌注（I／R）损伤的保护作用及机制。方法将24只C57BL／6小鼠编号后应用随机数字表分成3组：假手术组（Sham组）、肾脏缺血再灌注组（I／R组）和奥曲肽预处理＋肾脏缺血再灌注组（OPC＋I／R组），每组8只。收集小鼠肾脏缺血再灌注24h后的血清及肾脏组织。采用相应试剂盒测定各组血清肌酐（SCr）及尿素氮（BUN）水平，苏木素-伊红（HE）染色比较肾脏组织损伤，试剂盒检测各组小鼠肾脏内丙二醛（MI）A）含量及超氧化物歧化酶（SOD）活性，Western blot检测肾脏组织内核因子E2相关因子2（Nrr2）、血红素加氧酶-1（HO-1）及核因子-κB（NF—κB）的蛋白表达。结果I／R组SCr及BUN[（113．38±18．39）ixmol／L、（32．31±6．66）mmol／L]均显著高于Sham组[（27．61±7．77）μmol／L、（11．82±2．56）mmol／L；t=12．153，P=0．000；t=8．124，P=0．000]。OPC＋L／R组SCr及BUN[（72．39±11．97）μmol／L、（22．12±3．75）mmol／L]均低于I／R组（t=5．285，P=0．000；t=3．774，P=0．003）；HE染色检测肾小管坏死评分，OPC＋I／R组[（2．13±0．64）分]较I／R组[（4．13±0．84）分]显著降低（t=5．736，P=0．000）；OPC＋I／R组MDA水平[（3．92±0．69）μmol／g]低于I／R组[（5．94±1．23）txmol／g，t=5．004，P=0．002]，OPC＋I／R组SOD活性[（34．64±6．77）kU／g]与I／R组[（24．05±6．15）kU／g]比较明显升高（t=3．276，P=0．006）；Western blot检测结果显示OPC＋I／R组Nrt2和HO-1相对表达量（4．60±0．88、4．76±0．87）高于I／R组（2．35±0．50、2．67±0．54；t=6．294，P=0．000；t=5．737，P=0．000），OPC＋I／R组NF—κB相对表达量（2．51±0．21）低于IZR组（5．02±0．75；t=7．434，P=0．000）。结论奥曲肽可激活肾脏Nrt2／HO-1通路提高抗氧化应激能力以及抑制NF—κB通路减轻炎性反应从而对小鼠肾脏I／R损伤起到保护作用。

Objective To investigate the protective effects of octreotide （OCT） on renal ischemia - reperfusion （I/R） injury and its underlying mechanism. Methods Mice were randomly divided into three groups （ n = 8） using randomized number table method ： Sham group, I/R group and octreotide precondi- tioning （OPC） ＋ I/R group. Mice in group Sham received no treatment of I/R. The renal I/R was established in group I/R and group OPC ＋ I/R. Serum and renal tissues from these mice were collected 24 h af- ter I/R. The levels of serum creatinine （SCr） and blood urea nitrogen （BUN） were measured. The renal injury was observed by hematoxylin - eosin （HE） staining. The contents of renal malondialdehyde （MDA） and the activities of superoxide dismutase （SOD） were tested. The levels of nuclear factor erythroid 2 - re- lated factor 2 （ Nrf2）, heme oxygenase - 1 （ HO - 1 ） and nuclear factor - kappa B （ NF - KB） expression in renal tissues were detected by Western blotting. Results The levels of SCr and BUN in I/R group [ （ 113.38 ± 18.39 ） μmol/L, （ 32. 31 ± 6. 66 ） mmol/L ] were significantly higher than in sham group [（27.61 ±7.77） μmol/L, （11.82±2.56） mmol/L; t=12.153, P=0.000; t=8. 124, P=0.000]. The levels of SCr and BUN in OPC ＋I/R group [ （72. 39 ± 11.97） μmol/L, （22. 12 ±3.75） mmol/L] were significantly lower compared to I/R group（ t = 5. 285, P = 0. 000 ; t = 3. 774, P = 0. 003 ）. Renal tu- bular injury scores in I/R group （4. 13 ±0. 84）were significantly higher than in OPC ＋ I/R group（2. 13 ± 0. 64 ; t = 5. 736, P = 0. 000）. The MDA levels in I/R group [ （5.94± 1.23）μmol/g ] were higher than in OPC ＋I/R group [（3.92 ±0.69） μmol/g; t=5.004, P=0. 002]. The SOD activities in I/R group [ （24. 05 ± 6. 15 ） kU/g ] were lower than in OPC ＋ I/R group [ （ 34. 64± 6. 77 ） kU/g ; t = 3. 276, P = 0. 006]. The relative expressions of Nrf2 and HO - 1 protein in OPC ＋ I/R group （4. 60 ± 0. 88, 4. 76 ± 0. 87） were significantly increased as compared with I/R group （2. 35 ±0. 50, 2. 67±0. 54; t =6. 294, P = 0.000; t=5.737, P=0.000）. The relative expression of NF -κB protein in OPC ＋ I/R group （2.51 ± 0. 21 ） was significantly decreased as compared with I/R group （5.02 ±0. 75 ; t =7. 434, P =0. 000）. Con- clusion OCT protects renal against I/R injury, which may be through activation of Nrf2/HO - 1 signaling pathway and downregulation of NF - κB expression.