Ginevri F, Trivelli A, Mutti A, Bergamaschi E, Fabbretti G, Callea F, Salvidio G, Altieri P, Perfumo F, Ghiggeri G M
Department of Nephrology, G. Gaslini Institute, Genoa, Italy.
Nephron. 1993;63(1):79-88. doi: 10.1159/000187147.
In this study, we examined the progression of chronic Adriamycin (ADR) nephropathy in mild leukopenic rats and tried to define the possible relationship between tubulointerstitial lesions and proteinuria in this model. Chronic ADR nephropathy was induced by 2 doses of ADR (2 mg/kg) in 32 Sprague-Dawley rats. Eight of these were randomly assigned to cyclophosphamide treatment (50 mg/kg), given intravenously every week, to keep the blood leukocyte count constantly lower than 5,000/mm3. Serial parameters were followed for 16 weeks including clearance studies with iothalamate and p-aminohippurate and the analysis of urinary protein composition by: (a) an enzymatic assay for beta-glucosidase; (b) specific ELISA using antibodies against rat albumin and RBP, and finally (c) two-dimensional electrophoresis. ADR-treated rats rapidly (within 2 weeks) developed massive proteinuria which was in constant increment throughout the disease evolution in each single component (i.e., high and low molecular weight proteinuria, enzymuria) and developed renal insufficiency. At week 8, in ADR rats, glomerulosclerosis was mild whereas tubulointerstitial infiltrates predominated, characterized mainly by CD4+ T lymphocytes while CD8+ T lymphocytes were inconspicuous, and macrophages were only occasionally present. All such alterations had worsened after 16 weeks when the tubulointerstitial infiltration was associated with marked interstitial fibrosis and tubular atrophy. Leukopenia induced by cyclophosphamide was in all cases associated with a net amelioration of renal histopathology reducing tubulointerstitial infiltrates (by 40%) and glomerulosclerosis (33 +/- 5 vs. 52.2 +/- 7.5% sclerotic glomeruli) and also ameliorated glomerular filtration indexes (Cl 780 +/- 40 vs. 447 +/- 66 microliters/min/kg-1). In spite of these differences, albuminuria and urinary-retinol-binding protein were comparable at weeks 4, 8 and 16 in this group, while urinary beta-glucosidase was decreased at week 16 (p < 0.001) in cyclophosphamide-treated rats. No other qualitative changes in urinary proteins were detectable by 2-dimensional electrophoresis during the disease development. We concluded that chronic leukopenia prevents interstitial cellular infiltration by lymphocytes, interstitial fibrosis and slows down the decline of renal function typical of chronic ADR nephropathy. Glomerulosclerosis is also reduced in leukopenic rats without any appreciable changes in the urinary excretion of high molecular weight proteins deriving from the glomerulus. Finally, the improvement in tubulointerstitial alteration is associated with the reduction in urinary lysosomal enzymes. Tubulointerstitial alterations are implicated with a prominent role in the progression towards renal failure in chronic ADR glomerulopathy.
在本研究中，我们检测了轻度白细胞减少大鼠慢性阿霉素（ADR）肾病的进展情况，并试图明确该模型中肾小管间质病变与蛋白尿之间的可能关系。通过给32只Sprague-Dawley大鼠注射2剂ADR（2mg/kg）诱导慢性ADR肾病。其中8只大鼠被随机分配接受环磷酰胺治疗（50mg/kg），每周静脉注射一次，以使血液白细胞计数持续低于5000/mm³。连续16周监测一系列参数，包括用碘他拉酸盐和对氨基马尿酸进行清除率研究，以及通过以下方法分析尿蛋白成分：（a）β-葡萄糖苷酶的酶法测定；（b）使用抗大鼠白蛋白和视黄醇结合蛋白抗体的特异性ELISA，最后（c）二维电泳。接受ADR治疗的大鼠迅速（在2周内）出现大量蛋白尿，且在疾病发展的整个过程中，各单一成分（即高分子量和低分子量蛋白尿、酶尿）均持续增加，并出现肾功能不全。在第8周时，ADR大鼠的肾小球硬化较轻，而肾小管间质浸润为主，主要特征为CD4⁺T淋巴细胞，CD8⁺T淋巴细胞不明显，巨噬细胞仅偶尔出现。16周后，所有这些改变均加重，此时肾小管间质浸润伴有明显的间质纤维化和肾小管萎缩。环磷酰胺诱导的白细胞减少在所有情况下均与肾脏组织病理学的明显改善相关，减少了肾小管间质浸润（减少40%）和肾小球硬化（硬化肾小球比例为33±5%对52.2±7.5%），并改善了肾小球滤过指标（Cl为780±40对447±66微升/分钟/千克⁻¹）。尽管存在这些差异，但该组在第4、8和16周时的蛋白尿和尿视黄醇结合蛋白相当，而环磷酰胺治疗的大鼠在第16周时尿β-葡萄糖苷酶降低（p<0.001）。在疾病发展过程中二维电泳未检测到尿蛋白的其他定性变化。我们得出结论，慢性白细胞减少可防止淋巴细胞引起的间质细胞浸润、间质纤维化，并减缓慢性ADR肾病典型的肾功能下降。白细胞减少大鼠的肾小球硬化也有所减轻，而源自肾小球的高分子量蛋白的尿排泄没有明显变化。最后，肾小管间质改变的改善与尿溶酶体酶的减少相关。肾小管间质改变在慢性ADR肾小球病向肾衰竭进展中起重要作用。
