山药对大鼠肾缺血再灌注损伤的保护作用

Protective effect of rhizoma dioscoreae in rats with renal ischemia-reperfusion injury

目的研究山药灌胃预处理对大鼠肾脏缺血再灌注损伤的保护作用和促进肾脏再生修复的作用。方法3～4周龄雄性大鼠60只随机分正常对照(A)组(n=6)、假手术对照(B)组(n=6)、缺血再灌注损伤山药灌胃预处理(C)组(n=24)及缺血再灌注损伤无菌生理盐水灌胃对照(D)组(n=24)。C、D组在缺血再灌注损伤前灌胃5d,在损伤后2、12、24、48h分别采集6只鼠的血并收获肾脏标本。4组标本进行尿素氮、肌酐、丙二醛测定,常规病理切片、细胞凋亡、免疫组化检测增殖细胞抗核抗体(PCNA)、激光共聚焦免疫荧光检测5-溴脱氧尿嘧啶核苷(BrdU)、同源盒基因2(Pax-2)。结果C组尿素氮、肌酐、丙二醛明显低于D组;缺血再灌注损伤2h可测到肾小管细胞凋亡,12h达高峰;C组凋亡指数明显低于D组;C组PCNA阳性肾小管细胞明显高于D组;C组检测到BrdU、Pax-2双标记阳性细胞;常规病理形态4组有其特有表现。结论山药灌胃预处理能减轻肾脏缺血再灌注损伤大鼠的多项检测指标,促进受损肾小管的再生修复和重建,有效保护了肾功能。肾脏缺血再灌注损伤后测到的BrdU、Pax-2双标记阳性细胞提示肾组织内的祖细胞参与了肾脏的修复再生。

Objective To investigate the renal protective effect of rhizoma dioscoreae pretreatment in rats with renal ischemia-reperfusion injury. Methods Sixty SD rats （3-4 weeks old） were randomly assigned into normal control （group A,n=6）, sham operated control （group B, n=6）, intra-gastric pretreatment of Rhizoma Dioscoreae （group C, n=24）, and placebo aseptic normal saline lavage pretreatment （group D, n=24）. The rats in group C and D were pretreated with rhiizoma dioscoreae and placebo, respectively, for five days before being subjected to bilateral renal vascular occlusion for 45 minutes. Six rats of each group were randomly euthanized for blood sampling and kidney harvesting at 2, 12, 24 and 48 h after reperfusion. The blood urea nitrogen （BUN） and serum creatinine （SCr） were measured with automatic biochemistry analyzer. The serum content of malondialdehyde （MDA） was determined with TBA methods. Renal morphologic changes were studied on hematoxylin and eosin （H＆E） stained sections. Renal tubular cell apoptosis was detected with TUNEL method. PCNA positive renal tubular cells were detected immunohistochemieally as proliferation index. Progenitor cells were identified as BrdU and Pax-2 double labeling cell and localized in the kidney by confocal microscopy. Results Scr, BUN and MDA levels in group C were significantly lower than those in group D at 12, 24 and 48 h after reperfusion. The tubular cell apoptosis was detected in the kidney at 2 h after ischemia-reperfusion injury and reached the highest level at 12 h. Renal apoptosis score in group C was much less than that in group D. There were more PCNA positive tubular cells in group C than those in group D, and BrdU and Pax-2 double labeling cells were localized in the renal tubules after ischemia-reperfusion injury. Conclusions Renal ischemia-reperfusion injury may result in significant histological damage and renal dysfunction. Rhizoma dioscoreae lavage pretreatment in rats results in the attenuation of oxidative damage and apoptosis, and enhancement of renal tubular cell proliferation. BrdU and Pax-2 double labeling cells were identified as progenitor cells participating in renal repair after ischemia-reperfusion injury.