中毒性急性肾衰早期肾近曲小管上皮细胞细胞骨架的改变

目的 :了解中毒性急性肾衰 (ARF)早期肾近曲小管上皮细胞 (PTC)细胞骨架微丝和微管的改变 ,并探讨其改变的机制。方法 :采用皮下注射氯化汞建立中毒性ARF模型 ,用免疫组化和电镜法观察中毒 6h和 12hPTC细胞骨架微丝和微管的改变 ,并用高效液相色谱法测试细胞内ATP水平。结果 :免疫组化显示微丝随着中毒时间的延长 ,PTC刷状缘损伤逐渐加重 ,胞浆内有片状肌动蛋白分布 ;电镜示中毒 6h微绒毛变成球形小体 ,中毒 12h微绒毛部分缺失 ;免疫组化微管示中毒 6hPTC严重受损 ,着色变浅、不规则 ,中毒 12h着色部分恢复 ;细胞内ATP水平随着中毒时间延长而逐渐下降。结论 :中毒性ARF时 ,PTC细胞骨架微丝和微管发生变化 ,微丝的改变可能与细胞内ATP水平相关。     

HIV-1 harboring renal tubular epithelial cell interaction with T cells results in T cell trans-infection

Renal biopsy data suggest that renal tubular cells may serve as a reservoir for HIV-1, however the mechanism underlying this finding has not been studied. Here we show that primary human renal proximal tubular epithelial cells (HRPTECs) have the potential to harbor HIV-1 through the DEC-205 receptor. The interaction of HIV-1 with DEC-205 results in the rapid internalization of the virus for lysosomal degradation, without establishing a productive infection. However, a small fraction of incoming virus escapes degradation and can be rescued by T cells. Since pH-modulating agents and an inhibitor of endosomal transport increased HIV-1 accumulation and trans-infection to T cells, it appears that HRPTECs endocytic compartments may be the site of viral persistence and transmission to target cells. The ability of T cells to rescue the virus from HRPTECs further supports the hypothesis that these cells have the potential to serve as a reservoir for HIV-1.     

尿本周蛋白促进肾小管上皮细胞凋亡的体外研究

多发性骨髓瘤(MM)患者尿本周蛋白(BJP)对肾近端小管上皮细胞(PTC)具有直接毒性,本研究通过体外观察BJP对PTC的凋亡作用以探讨BJP对PTC的部分毒性机制。将自MM患者尿中提取并经免疫固定法琼脂糖凝胶电泳进行鉴定的4例κ和λ型BJP以不同浓度与大鼠NRK52E株PTC共同培养12～48h,用原位末端标记法、流式细胞仪及透射电镜检测凋亡。结果显示:①BJPκ组与BJPλ组BJP为10mg/ml与20mg/ml时诱导PTC凋亡的比例明显高于对照组及5mg/ml,两组诱导PTC凋亡的比例随着培养时间的延长而显著增加且明显高于空白对照组;②BJPκ组与BJPλ组之间诱导PTC凋亡的比例无明显差异。结果表明,κ与λ型BJP均可诱导PTC凋亡,且随着BJP浓度及培养时间增加而增强。     

益母草防治初发期急性肾小管坏死的实验研究

ＳＤ成年雄性大鼠，禁止１６小时，肌注甘油引起急性肾小管坏死（ＡＴＮ），于其初发期给予不同药液，观察到益母草组３、２４及４８小时Ｂｃｒ升高值，２４及４８小时ＢＵＮ升高值均明显低于自来水组和单纯禁水组，而与校正对照异搏停组近似，肾组织损伤程度亦明显减轻。结果表明，益母草对初发期急性肾小管坏死（ＩＡＴＮ）有一定的防治作用。     

敲低Txnip抑制高糖诱导的人肾小管细胞系凋亡

目的观察敲低Txnip对高糖诱导人肾小管上皮细胞凋亡的影响。方法将体外培养人肾小管上皮细胞分为正常糖组、高糖组、高糖+质粒载体对照组及高糖+shRNA组。采用原位末端转移酶标记技术(TUNEL)检测细胞凋亡;流式细胞术检测细胞ROS水平;Western blot检测caspase-3、cleaved caspase-3、BAX、BCL-2、P38 MAPK、P-P38 MAPK及细胞色素c的表达。结果与正常糖组相比,高糖组肾小管上皮细胞ROS产生和细胞凋亡明显增加(P0.01),cleaved caspase-3和P-P38 MAPK表达增高,BAX/BCL-2比率明显升高以及细胞色素c易位(P0.05)。敲低Txnip能够显著抑制高糖诱导的肾小管上皮细胞凋亡和ROS产生,下调cleaved caspase-3、和P-P38MAPK的表达,减少BAX/BCL-2比率和细胞色素c易位(P0.05)。结论敲低Txnip能够抑制高糖诱导的人肾小管上皮细胞凋亡可能是通过减少ROS产生,保护线粒体功能,抑制P38MAPK信号通路激活而实现的。     

Morphologic changes in tubular cells from in situ kidneys following experimental hypothermia and rewarming

Although renal failure may occur following rewarming from deep accidental hypothermia, this subject has received little attention in experimental hypothermia and clinical case reports. In order to explore the integrity of hypothermic and posthypothermic renal morphology we used an experimental animal model of accidental hypothermia where the heart supports the circulation throughout cooling and rewarming without accompanying cardioplegia or ischemia. Ultrastructural changes in renal tubular cells from three groups of pentobarbital anesthetized Wistar rats: 1) controls (n=6) maintained at 37 degrees C for 4 h, 2) hypothermic rats (n=6) core-cooled and maintained at 15-13 degrees C for 4 h, and 3) rewarmed rats (n=10), were studied as a sensitive indicator of renal damage. Electron micrographs (EM) from hypothermic kidneys showed rounded up mitochondria with loss of contrast. These changes were observed in several though not all of the biopsies, but they were found in all kidneys. Areas exhibiting focal tubular necrosis were seen on most EM from three of these kidneys. EM from rewarmed kidneys showed alterations of mitochondrial ultrastructure with similarities to those observed after hypothermia, but in general the changes were more prominent. Extracellular edema, intracellular edema, swelling of mitochondria, margination of chromatin, necrosis of single tubular cells, and disrupting necrotic debris into tubular lumen could be found in micrographs from 7 of the 10 kidneys examined. Rewarming from experimental hypothermia, without episodes of ischemia or hypoxia, thus induces ultrastructural changes in renal tubular cells similar to changes observed in acute tubular necrosis, associated with renal failure.     

Distribution of cadmium and metallothionein in CdCl2-exposed rat kidney: Relationship with apoptosis and regeneration

Male Sprague-Dawley rats were injected subcutaneously with 0.6 mg cadmium/kg bodyweight per day for 6 weeks. In each week of exposure, rats were killed and the localization of cadmium and metallothionein in the kidney was studied by histochemical and immunohistochemical methods. Although cadmium was localized throughout the proximal tubules during exposure, apoptosis and subsequent regeneration were observed mainly in the straight portion of the proximal tubules after 4 weeks of exposure. The distribution of tubular injury may thus not necessarily coincide with that of cadmium. Expression of metallothionein was also detected in the cytoplasm and nuclei of the convoluted and the straight portion of the proximal tubules, but the latter became positive in accordance with apoptosis and regeneration. These results suggest a close relationship between metallothionein distribution and tubular cell regeneration.     

Regulation and production of IL-8 by human proximal tubular epithelial cells in vitro

A number of inflammatory kidney diseases are associated with interstitial nephritis and influx of leucocytes in the renal interstitium. Potentially the influx of neutrophils in the interstitium may be induced by the chemotactic cytokine IL-8. In the present study we have analysed the production of IL-8 by cultured human proximal tubular epithelial cells (PTEC) in response to a number of proinflammatory cytokines. Primary cell lines of proximal tubular epithelium obtained from ten different kidneys, and cultured under serum-free conditions, were found to produce IL-8 to different degrees from not detectable levels up to 10·8±1·5 ng IL-8 per 1×10⁵ cells in 72 h. Gel filtration chromatography of PTEC supernatant indicated that the size of IL-8 of PTEC is 15·1 and 8·1 kD, and is chemotactically active for polymorphonuclear neutrophils (PMN). Addition of 0·5 ng/ml rIL-1α or 1000 U/ml recombinant tumour necrosis factor-alpha (TNF-α) to the culture media of PTEC induced an up-regulation of IL-8 production up to 6·3-fold and 3·0-fold, respectively. The up-regulation by IL-1α and TNF-α was dose- and time-dependent. In contrast, 500 U/ml recombinant interferon-gamma (rIFN-γ) down-regulated the production of IL-8 3·4-fold. Northern blot analysis showed that IL-1α and TNF-α increased the expression of IL-8 mRNA, whereas IFN-γ reduced IL-8 mRNA expression. Taken together, these experiments indicate that human PTEC are a potential source of IL-8 in the kidney, and that IL-8 produced in the proximal tubule can be induced by various proinflammatory cytokines.     

尿本周氏蛋白及转化生长因子β1对肾近端小管上皮细胞增殖的影响

目的:研究多发性骨髓瘤(MM)患者尿本周氏蛋白(BJP)及转化生长因子β₁(TGF-β₁)在体外对肾近端小管上皮细胞(PTC)增殖的影响。方法:将自MM患者尿中提取的λ型BJP和/或TGF-β₁与大鼠NRK.52E株PTC共同培养, 用[H³]TdR掺入研究PTC增殖。并用ELISA法测定BJP与PTC培养上清液中的TGF-β₁含量。结果:①100-800μmol/LBJP以浓度依赖方式抑制PTC增殖, 当浓度≥400μmol/L与对照组比较有显著差异(P＜0.05), 当加入2μg/LTGF-β₁共同培养, 在BJP浓度为400μmol/L时, [H³]TdR掺入低于单用BJP(P＜0.05), 但与单用BJP浓度为800μmol/L无显著差异;②100-800μmol/LBJP与PTC共同培养液中的TGF-β₁含量均增加, 尤以BJP为400μmol/L明显大于对照组(P＜0.05);③外源性0.5-10μg/LTGF-β₁与PTC共同培养, [H³]TdR掺入随TGF-β₁浓度增加而减少。结论:MM患者λ型BJP可抑制PTC的增殖, 其部分机理可能与其促进对PTC增殖也有抑制作用的TGF-β₁过度产生有关。     

Induction of apoptosis in human renal proximal tubular epithelial cells by Escherichia coli verocytotoxin 1 in vitro

Verocytotoxin 1 and 2 (VT1 and 2) produced by verocytotoxin-producing Escherichia coli have been considered to play an important role in the pathogenesis of glomerular and tubular damage in the epidemic form of hemolytic uremic syndrome (HUS). VTs are known to be cytotoxic to culture cells by inhibiting cellular protein synthesis. In this in vitro study, the mechanism(s) of tubular damage in HUS and the ability of VT1 to induce apoptosis in normal human renal proximal tubular epithelial cells (HRPTEC) were examined. VT1 markedly reduced cell viability of HRPTEC and rapidly inhibited overall protein synthesis. VT1 directly induced apoptotic cell death in HRPTEC in a dose- and time-dependent fashion, and co-incubation with tumor necrosis factor-α enhanced the VT1-induced apoptosis. These results suggest that apoptosis induced by VT1, possibly in concert with host cytokines, in renal tubular cells may contribute to the tubular damage in HUS. Received: 15 December 1998     

Plasma cell dyscrasia with kappa light-chain crystals in proximal tubular cells: a histological, immunofluorescent, and ultrastructural study

This is a case report of a 56-year-old man with plasma cell dyscrasia who presented with proximal tubulopathy manifested as kappa light-chain crystal deposition in the proximal convoluted tubular cells. This was associated with mild cellular damage. The crystals were seen as negative images with the hematoxylin-eosin and periodic acid-Schiff (PAS) stains. They were identified as kappa light-chains by immunofluorescent imaging and confirmed by immunoelectron microscopy. Ultrastructurally, the crystals appear to be located within lysosomes. No deposits of light-chains were seen elsewhere in the kidney biopsy.     

Proximal tubular function in adult rats treated neonatally with enalapril

Neonatal treatment with angiotensin-converting enzyme (ACE) inhibitors or the angiotensin II type-1 receptor antagonist losartan in rats induces irreversible renal histological abnormalities, mainly papillary atrophy, in association with an impairment in urinary concentrating ability. The aim of the present study was to assess proximal tubular function in adult rats treated neonatally with enalapril. Male Wistar rats received daily, intraperitoneal injections of either enalapril (10 mg kg^?1) or isotonic saline vehicle from 3 to 24 days of age. In 15-week-old, hydropenic rats we analysed: (i) proximal tubular iso-osmotic fluid reabsorption using the method of lithium clearance; and (ii) maximal tubular D -glucose reabsorption (Tm_G), under pentobarbital anaesthesia. The main findings were that neonatally enalapril-treated rats showed: (i) reductions in absolute (APRH₂O) and fractional (FPRH₂O) iso-osmotic fluid reabsorption in the proximal tubules (APRH₂O: 0.50 ± 0.02 vs. 0.64 ± 0.03 mL min^?1 g KW^?1, P < 0.05; FPRH₂O: 58 ± 3 vs. 68 ± 2%, P < 0.05); and (ii) a normal Tm_G. In addition, during baseline clearance measurements neonatally enalapril-treated rats showed increases in urine volume and fractional excretion rates of sodium and potassium, a reduction in urine osmolality, whereas glomerular filtration rate and effective renal plasma flow were unaltered. These results suggest that neonatal ACE inhibition produces an irreversible, but differentiated, abnormality in proximal tubular function. Thus, the development of a normal proximal tubular function in the rat seems to be dependent on an intact renin-angiotensin system, (RAS) neonatally.     

Acinar cell apoptosis and the origin of tubular complexes in caerulein-induced pancreatitis

The interrelationship between acinar cell apoptosis and tubular complex formation was examined in caerulein-induced pancreatitis using histology, immunohistochemistry, electron microscopy and DNA gel electrophoresis. Rats were given 8 hourly subcutaneous injections of caerulein, 24 micrograms/kg, for up to 2 days. Morphologically and biochemically typical apoptosis affected 4.6 and 8.9% of acinar cells at 1 and 2 days, respectively, resulting in removal of most acinar cells by 2 days. Consequently, pancreatic ducts, the lining cells expressing bcl-2 and therefore resistant to apoptosis, became much more closely approximated to form the basis of tubular complexes; small numbers of immunohistochemically discrete acinar cells in their lining were either pre-apoptotic resistant to it or newly formed. Proliferation of duct-like lining cells was associated with apoptosis, an increase in islet cells and acinar cell regeneration. There was evidence of duct to acinar cell differentiation but the main increase in acinar cell numbers appeared to derive from proliferation of newly formed acinar cells.     

糖皮质激素诱导的蛋白激酶3种亚型在高糖诱导的人肾小管上皮细胞中的表达

目的：研究高糖环境下人近端肾小管上皮细胞（HKC）中血清和糖皮质激素诱导的蛋白激酶（SGK）3种亚型SGK1、SGK2和SGK3的表达，探讨SGK 3种亚型在介导高糖致肾小管上皮细胞过度合成细胞外基质（ECM）中的作用。 方法: 将细胞分为对照组、高糖组和渗透压对照组。分别采用RT-PCR方法和Western blotting方法检测SGK1、SGK2和SGK3 mRNA水平和SGK1蛋白水平的表达，ELISA方法和间接免疫荧光方法检测培养液中和HKC胞内纤连蛋白（FN）含量。 结果: HKC细胞中存在SGK1、SGK2和SGK3的表达。高糖刺激下， SGK1、SGK2和SGK3 mRNA和SGK1蛋白表达明显升高（P<0.01）；同时伴有HKC FN合成和分泌的增加，这与SGK上调存在一定联系。 结论: 高糖能促进近端肾小管上皮细胞SGK1、SGK2和SGK3的表达，并可能通过SGK1、SGK2和SGK3介导的信号转导途径促进细胞外基质积聚，可能在糖尿病肾病的发生和发展中发挥致病作用。     

Proximal tubular cell sodium concentration in early diabetic nephropathy assessed by electron microprobe analysis

Electron microprobe X-ray analysis techniques were employed in order to assess the changes that occur in proximal tubular cell sodium concentration during the hyperfiltration phase of early diabetes mellitus induced by streptozotocin in Sprague Dawley rats. Intracellular rubidium accumulation following intravenous infusion of rubidium chloride was used as a marker of basolateral Na/K-ATPase activity. The diabetic animals studied had a significantly higher glomerular filtration rate compared with controls [1.44±0.07 vs. 1.00±0.07 ml min^–1 (100 g body weight)^–1; mean±SEM, P<0.001]. Intracellular Na concentration was significantly higher in diabetic animals (19.5±0.6 vs. 17.8±0.4 mmol/kg wet weight; P<0.01). Concurrent measurement of Rb demonstrated significantly higher intracellular accumulation in the proximal tubules of diabetic animals compared with control (7.9±0.5 vs. 5.5±0.5 mmol/kg wet weight; P<0.001). These results indicate that proximal tubular Na/K-ATPase activity is enhanced in the hyperfiltration phase of diabetes mellitus. Since, however, intracellular Na concentration is increased under these conditions, it may be inferred that apical Na entry into proximal tubular cells is stimulated beyond the rate of basal exit during the initial development of hyperfiltration. The reasons for these alterations in cellular Na transport are unclear but similar changes have been implicated in the pathogenesis of cell growth.     

新的组织工程种子细胞--内皮祖细胞

内皮祖细胞作为一种在血管领域的干细胞在组织工程中有着广阔的应用前景.内皮祖细胞取材方便,参与新生血管的形成,具有成熟内皮细胞相似的特性.因此,内皮祖细胞可能是组织工程血管、血管植入物再内皮化以及构建组织工程器官血管网络的种子细胞的理想来源.简单介绍了内皮祖细胞的来源、特性以及体外扩增技术,并对其在组织工程中应用的研究进展做一回顾.     

新的组织工程种子细胞——内皮祖细胞

内皮祖细胞作为一种在血管领域的干细胞在组织工程中有着广阔的应用前景。内皮祖细胞取材方便，参与新生血管的形成，具有成熟内皮细胞相似的特性。因此，内皮祖细胞可能是组织工程血管、血管植入物再内皮化以及构建组织工程器官血管网络的种子细胞的理想来源。简单介绍了内皮祖细胞的来源、特性以及体外扩增技术，并对其在组织工程中应用的研究进展做一回顾。