单侧输尿管梗阻大鼠模型中p38MAPK表达与细胞凋亡

目的： 探讨p38MAPK在大鼠单侧输尿管梗阻(UUO)模型肾组织中的表达及其在肾小管间质细胞凋亡和纤维化过程中可能发挥的作用。方法: 将25只Wistar大鼠中的18只行左侧输尿管结扎术，另外7只行假手术。分别于术后第3、7和14 d处死各组大鼠，行HE和Masson染色，观察肾脏病理变化；免疫组织化学方法测定增殖细胞核抗原（PCNA）表达；原位末端标记法（TUNEL）与DNA电泳观察肾小管间质细胞凋亡情况；Western blotting检测肾组织半胱氨酸天门冬氨酸蛋白酶-3（caspase-3）和p38丝裂素激活蛋白激酶（p38MAPK）及其磷酸化产物（p-p38MAPK）的表达。结果: 与假手术组比较，UUO模型组肾脏病理改变加重，TUNEL染色及DNA琼脂糖凝胶电泳可见大量的肾小管间质细胞凋亡，肾间质细胞PCNA表达明显增加，肾组织caspase-3的表达也显著增加（P<0.05）。p38MAPK蛋白水平在各组之间比较没有明显差别（P>0.05）。p-p38MAPK蛋白在正常肾脏有低水平表达，UUO模型组随着梗阻时间延长表达逐渐增多；第7 d达高峰，第14 d开始下降（P<0.05）。结论: p38MAPK信号通路可能参与了UUO致肾小管间质细胞凋亡和肾间质纤维化过程。

p38MAPK expression and apoptosis in the rat unilateral ureteral obstruction model

AIM: To investigate the expression of p38 mitogen-activated protein kinase (p38MAPK) in the kidney after unilateral ureteral obstruction (UUO) in rats and the functional role of it on apoptosis and fibrosis. METHODS: Eighteen Wistar rats underwent UUO were killed at 3, 7, 14 days. Additional 7 rats were sham operated. Histological changes were observed by HE and Masson staining. Immunohistochemistry study was performed on renal tissue for proliferating cell nuclear antigen (PCNA). Apoptotic cells were determined by terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling (TUNEL) and the electrophoresis analysis of genomic DNA. Western blotting of cysteinyl aspartate specific proteinase-3 (caspase-3), p38MAPK and p-p38MAPK were measured. RESULTS: UUO induced a significant increase in renal tubular and interstitial cell apoptosis, immunohistochemistry of PCNA and Western blotting of caspase-3, p-p38MAPK as well as severe morphology changes. However, there was no significant difference between UUO and the control in Western blotting of p38MAPK. CONCLUSION: An in vivo model of renal fibrosis after UUO demonstrates that activated or phosphorylated p38MAPK plays a role in apoptosis of renal tubulointerstitial cells.