Truong L D, Foster S V, Barrios R, D'Agati V, Verani R R, Gonzalez J M, Suki W N
Department of Pathology, Methodist Hospital, Houston, TX 77030, USA.
Nephron. 1996;72(4):579-86. doi: 10.1159/000188943.
Tenascin, a large oligomeric glycoprotein, is a recent addition to a list of increasing extracellular matrix proteins. Previous studies have documented the strong expression of tenascin in embryonic kidney and in both normal and abnormal mature glomeruli implicating an important role of this extracellular matrix protein in nephrogenesis and glomerular scarring. Whether tenascin plays any role in interstitial fibrosis, a common final pathway of tubulointerstitial nephritis, is no known; on the other hand, a detailed knowledge of the structural components of interstitial fibrosis is essential for further studies on other fundamental aspects of this biologically and clinically important process. In this study, the expression of tenascin in the renal interstitium was immunohistochemically evaluated in 208 renal specimens during normal kidney (23 cases), acute tubular necrosis (8), acute tubulointerstitial nephritis (8), chronic primary tubulointerstitial nephritis (30), tubulointerstitial nephritis secondary to glomerular diseases of mild (46) and severe (55) degree, ischemic damage (24), and rejection (14). It was found that in normal kidney tenascin expression was limited to the medullary interstitium. In kidney with tubulointerstitial nephritis, tenascin was ubiquitously and constantly expressed in any areas with tubulointerstitial damage regardless of diagnosis, etiology, the cortical vs. medullary location of the lesions, stage of the fibrogenetic process, density of fibroblasts, or severity of interstitial inflammation in the affected areas. Indeed, strong tenascin expression was seen in areas where there was only interstitial edema or inflammation as judged by routine light microscopic preparations. In summary, this study systematically documents tenascin as a novel extracellular matrix protein selectively expressed in the medullary interstitium in normal kidney, and ubiquitously present in areas with interstitial fibrosis.
腱生蛋白是一种大型寡聚糖蛋白，是细胞外基质蛋白不断增加的列表中的新成员。先前的研究已证明腱生蛋白在胚胎肾以及正常和异常成熟肾小球中强烈表达，这表明这种细胞外基质蛋白在肾发生和肾小球瘢痕形成中起重要作用。腱生蛋白在肾小管间质性肾炎的常见终末途径——间质纤维化中是否起任何作用尚不清楚；另一方面，详细了解间质纤维化的结构成分对于进一步研究这个生物学和临床上重要过程的其他基本方面至关重要。在本研究中，采用免疫组织化学方法评估了208例肾脏标本中腱生蛋白在肾间质中的表达情况，这些标本包括正常肾脏（23例）、急性肾小管坏死（8例）、急性肾小管间质性肾炎（8例）、慢性原发性肾小管间质性肾炎（30例）、轻度（46例）和重度（55例）肾小球疾病继发的肾小管间质性肾炎、缺血性损伤（24例）和排斥反应（14例）。结果发现，在正常肾脏中，腱生蛋白的表达仅限于髓质间质。在患有肾小管间质性肾炎的肾脏中，无论诊断、病因、病变的皮质与髓质位置、纤维化过程的阶段、成纤维细胞密度或受影响区域的间质炎症严重程度如何，腱生蛋白在任何存在肾小管间质损伤的区域均普遍且持续表达。事实上，根据常规光学显微镜观察，在仅有间质水肿或炎症的区域可见腱生蛋白的强表达。总之，本研究系统地证明了腱生蛋白是一种新型细胞外基质蛋白，在正常肾脏中选择性地表达于髓质间质，而在存在间质纤维化的区域普遍存在。
