管周毛细血管损害引起的低氧对大鼠慢性马兜铃酸肾病进展的影响

目的研究慢性马兜铃酸肾病(CAAN)管周毛细血管(PTC)的损害特点以及PTC损害引起的低氧对CAAN进展的影响。方法将54只Wistar大鼠随机分为2组关木通组(30只)大鼠予关木通水煎剂灌胃连续用药8周,在第8、12、16周分别处死10只大鼠;对照组(24只)大鼠予饮用水灌胃,连续8周,在第8、12、16周分别处死8只大鼠。留取血、尿、肾组织标本分别作生化、病理、免疫组织化学、免疫印迹等检查。结果关木通组大鼠从第8周开始,肾功能逐渐恶化、尿蛋白增加,PTC损害加重,PTC密度减少,血管内皮生长因子(VEGF)表达逐渐减少,但低氧诱导因子1α(HIF-1α)表达逐渐增加。第16周时两组比较(1)对照组HIF-1α-IOD值为(0·49±0·06)×103,关木通组HIF-1α-IOD值为(7·11±1·20)×103(P<0·01);(2)对照组PTC密度为(42·80±4·49)/0·13mm2,关木通组PTC密度为(8·10±2·28)/0·13mm2(P<0·01);(3)对照组VEGF-IOD值为(26·94±9·34)×103,关木通组VEGF-IOD值为(2·78±0·78)×103(P<0·01)。肾间质面积第8周较对照组减小,第12周开始逐渐增大,第16周明显增大。结论CAAN大鼠存在严重的PTC损害和低氧,缺血、缺氧与CAAN的进展有关。

Influence of hypoxia caused by impairment of peritubular capillary on the progression of chronic aristolochic acid nephropathy

OBJECTIVE: To investigate the manifestation of impairment of peritubular capillary (PTC) in chronic aristolochic acid nephropathy (CAAN) and the influence of hypoxia caused by PTC impairment on the progression of CAAN. METHODS: Fifty-four Wistar rats were randomly divided into 2 groups: Group A (n = 30, perfused intragastrically with decoction of Caulis aristolochia manchuriensis for 8 weeks) and Group B (n = 24, perfused intragastrically with drinking water for 8 weeks). At weeks 8, 12, and 16 ten rats in Group A and 8 rats in Group B were killed. Specimens of blood and urine were collected before the killing of the rats to detect the blood urea nitrogen (BUN), serum creatinine (Scr), and urine protein. HE and Masson staining and microscopy were used to observe the pathology of the kidney. Immunohistochemistry and Western blotting were used to detect the expression of hypoxia-inducible factor-1alpha (HIF-1alpha), vascular endothelial growth factor (VEGF), and CD34. Correlation analysis was conducted to study the relationships among these indices. RESULTS: Since week 8 BUN, Scr, and urine protein of Group A began to increase in comparison with Group B (all P < 0.05). Pathological changes of the kidney began to appear in Group A since week 8 with the decrease of PTC density. HIF-1alpha was not expressed in Group B, and in Group A HIF-1alpha expression began to increase since week 8 and became significantly higher than that of Group B since week 12. At week 16, the PTC density and VEGF-IOD of Group A were 8.10 +/- 2.28/0.13 mm(2) and (2.78 +/- 0.78) x 10(3) respectively, both significantly lower than those of Group B (42.80 +/- 4.49)/0.13 mm(2) and (26.49 +/- 9.34) x 10(3) respectively, both P < 0.01], and the HIF-1alpha-IOD of Group A was (7.11 +/- 1.20) x 10(3), significantly higher than that of Group B (0.44 +/- 0.10) x 10(3), P < 0.01]. CD34 was highly expressed in Group B, and the CD34 expression of Group A began to decrease since week 16. HIF-1alpha expression was positively correlated with Scr (r = -0.945, P < 0/01), and PTC density and VEGF expression were negatively correlated with Scr (r = -0.907, P < 0.01 and r = -0.690, P < 0.01). PTC density was negatively correlated with HIF-1alpha expression (r = -0.880, P < 0.01). CONCLUSION: Severe hypoxia exists following PTC injury in CAAN. Hypoxia is correlated with the progression of CAAN.