慢性马兜铃酸肾病大鼠肾小管上皮细胞转分化与肾间质纤维化的关系

Relationship Between Tubular Epithelial-Myofibroblast Transdifferentiation and Renal Interstitial Fibrosis in Rats with Chronic Aristolochic Acid Nephropathy

目的:研究慢性马兜铃酸肾病(CAAN)大鼠肾小管上皮细胞-肌成纤维细胞转分化(TEMT)与肾间质纤维化之间关系。方法:雄性SD大鼠随机分为2组,每组12只。模型组予关木通浸膏水溶液灌胃制成CAAN模型,对照组予自来水灌胃。于第4周和第16周末分批处死大鼠,取肾组织切片做免疫组化Ⅰ型胶原(ColⅠ)染色、α-平滑肌肌动蛋白(α-SMA)染色、α-SMA及增殖细胞核抗原(PCNA)双染,然后进行图像分析。结果:与对照组比较,模型组中α-SMA+肾小管百分数、α-SMA+PCNA+肾小管上皮细胞(TEC)数、肾间质α-SMA+细胞数及肾间质ColⅠ相对阳性面积均显著增加(P<0.01),其中前二者分别与后二者呈显著正相关(P<0.05或P<0.01)。在模型组的肾组织中观察到部分α-SMA+TEC失去正常形态,其相邻肾小管基底膜断裂,α-SMA+TEC出现于裂孔中,正向间质迁移。结论:CAAN大鼠TEC再生时即可发生TEMT,而此TEMT与肾间质纤维化密切相关。

Objective： To investigate the relationship between renal tubular epithelial- myofibroblast transdifferentiation （TEMT） and renal interstitial fibrosis in the rats with chronic aristolochic acid nephropathy （CAAN）. Method： Male Sprague - Elawley rats were randomly divided into two groups. Each consisted of 12 rats. The rats in CAAN groups received 20 mg-kg^- 1·d^-1 aristolochic acid contained in the ethanol extract of Aristolochia manshuriensis Kom by gavage for continuous 5 days in the first two weeks, and then 15 mg·kg^- 1· d^- 1 for continuous 7 days in every other week up to 16th week. Control group （CTR） only received tap water by gavage. At the end of 4th and 16th week, 6 rats of each group were killed. Immunohistochemicial staining was performed on their kidney tissue sections to examine the expression of type I collagen （Col Ⅰ ）, α- smooth muscle actin （α- SMA, with PAN counterstaining. ） and proliferating cell nuclear antigen （PCNA, with α- SMA double immunohistochemicial staining）. Results：Compared with CTR, the percentage of α- SMA^＋ tubules, the number of α- SMA^＋ PCNA^＋ tubular epithelial cells （TEC）, the number of interstitial α- SMA^＋ cells and the relatively positive area of Col Ⅰ were all significantly increased in CAAN group （P〈0.01）, and there were significant positive correlations between each of the foregoing two items and each of the latter two items in CAAN group （P〈0.05 or 0.01）. In the sections of CAAN group, the α-SMA^＋ TEC with lost normal appearance and apical - basal polarity often associated with local disruptions of the tubular basement membrane, and these TEC appeared to be migrating into the peritubular area through the damaged TBM. Conclusion： TEMT may take place with regeneration of renal tubular cells in CAAN rats, which is closely associated with the development of renal interstitial fibrosis.