石蜡切片行免疫荧光染色后再行PAS或HE染色确定NPR-A蛋白在肾脏的定位

目的 介绍一种新方法来明确NPR-A蛋白在大鼠肾组织的定位.方法 采用肾脏石蜡切片先行NPR-A免疫荧光染色,然后再行PAS或HE染色.结果 NPR-A免疫阳性物在大鼠肾组织主要沉积于皮质的近端小管、外髓的髓袢升支粗段以及内髓集合管,直小血管、肾小球、远曲小管和细段也有一定量的表达,而皮质及外髓集合管仅有少量的表达.结论 研究采用石蜡切片先行免疫荧光染色后再行PAS或HE染色,在不用或少用特异性抗体的情况下,成功的解决了NPR-A蛋白在大鼠肾组织表达的分布位置及细胞定位的难题.     

双峰驼肾重吸收机能的细胞学证据

电镜下观察了18峰双峰驼（Camelus bactrianus)肾脏细胞的超微结构,探究驼肾重吸收机能的形态学证据。结果显示,驼肾近曲小管的刷状缘高而密集,上皮细胞胞质顶端具有丰富的管泡结构,侧基底指状突起和基底质膜内褶多而明显,板状嵴线粒体发达。远曲小管和远直小管游离面微绒毛短而稀少,胞质线粒体排列密集,质膜内褶更为发达。集合小管上皮包括多量的亮细胞和少量的暗细胞两种类型,亮细胞结构简单,线粒体稀少,暗细胞线粒体密集,由皮质至髓质,暗细胞数量呈递减趋势,但内髓仍见暗细胞分布。皮质间质极少,志细血管丰富,管壁内皮菲薄有孔。髓质直小血管亦为有孔内皮。上述结构特征表明,双峰驼具有很强的重吸收能力,与其节水耐干渴特性相适应。     

金雕肾脏的组织学观察

利用生物显微技术观察了金雕Aquila chrysaetos肾脏的组织结构.结果表明,金雕肾实质由许多肾小叶构成,每个肾小叶可分为皮质和髓质两部分.肾单位由一个肾小体和一条与其相连的肾小管构成.肾小体由肾小囊和肾小球组成.肾小管分为近曲小管、髓袢、远曲小管和连接小管.集合管分为小叶周集合小管和髓质集合管两部分.具有发达的极周细胞.     

肾小管的功能分段

近年来,随着超微结构和肾单位微穿刺灌注研究的发展,特别是发展了游离肾小管段体外灌注和质膜囊泡等新技术,对肾小管各段结构和功能的差异性有了更深入的认识。现在一般认为,肾小管按其形态和功能特征,可依次分为下列11个标准段:(1)近曲小管(PCT);(2)近直小管(PST)或称直部(PR);(3)髓袢降支细段(DTLH);(4)髓袢升支细段(ATLH);(5)髓袢升支髓质粗段(MTALH);(6)髓袢升支皮质粗段(CTALH),     

肾小球旁器组织结构及其生理作用

肾单位包括肾小体和肾小管两部分,肾小体的功能为超滤过作用,肾小管主要是再吸收作用。肾小管又分为近曲小管、髓袢及远曲小管几部分。由若干肾单位的远曲小管汇合成为集合管,再开口于锥体乳头处。集合管不属于肾单位,它和肾单位的胚胎发育来源不同。肾小体、近曲小管、远曲小管以及集合管的一部分位于肾皮质内、髓袢、直集合管和直血管位于髓质锥体之内,因此在断面上可见皮质呈现颗粒状,髓质为纹状。肾小球旁器也称球旁复合体或近血管球复合体,由入球小动脉的球旁细胞、远曲小管的致密斑和球外系膜细胞组成。三者在肾小体血管极处排列成三角形,入球小动脉和     

棕熊肾脏的解剖学及光电镜观察

本文观察了棕熊肾脏的大体解剖和光、电镜下的组织结构。棕熊的肾脏为分叶肾,每个肾叶为多面锥体形。光镜下H—E染色切片标本可见肾实质有皮质和髓质两部分。皮质可见清晰的皮质迷路和髓放线结构。肾小体可分出血管极和尿极。血管球由毛细血管缠绕形成,外包有肾小囊。近曲小管管腔面可见刷状缘。在透射电镜下可见到摅过屏障由有孔内皮、基膜及足细胞的次级突起构成。电镜下还可看到近曲小管游离面紧密排列的微绒毛和基底面的质膜内褶结构。     

华鲮泌尿系统组织学的初步观察

2004年3月至9月采用常规组织学方法对华鲮泌尿系统作了研究,结果表明：华鲮泌尿系统包括中肾、输尿管、膀胱。中肾由肾小体和肾小管组成,无皮质、髓质之分,有肾小体聚集现象;肾小管可分为颈段、第一近曲小管、第二近曲小管、远曲小管、集合管。肾中散布有大量淋巴髓样组织,还有甲状腺滤泡和斯坦尼氏小体,显然华鲮的肾脏是一个具有多种生理功能的复合器官。输尿管位于两肾叶腹侧,其上皮为似复层,缺黏膜下层,无纵肌,外膜甚薄。左右输尿管在后端合并,稍微扩大,形成膀胱,膀胱内壁具有发达的绒毛,绒毛表面为变移上皮。     

版纳鱼螈泌尿系统解剖学及组织学观察

采用常规解剖学和组织学方法对版纳鱼螈Ichthyophis bannanica的泌尿系统进行研究.结果表明,版纳鱼螈泌尿系统包括中肾、输尿管、膀胱.版纳鱼螈的中肾由肾小体和肾小管组成,无皮质、髓质之分,肾小体主要分布在肾脏背外侧缘,肾小管由颈段、第1近曲小管、第2近曲小管、间段、第1远曲小管、第2远曲小管和集合管组成;输尿管位于两肾外侧缘,其上皮由前端的单层立方上皮过渡到后端的假复层上皮;膀胱为泄殖腔膀胱,内壁具有发达的绒毛,绒毛上皮为变移上皮.     

贝氏高原鳅泌尿系统显微和超微结构

贝氏高原鳅(Triplophysa bleekeri)泌尿系统由中肾、输尿管、膀胱构成。头肾极小。中肾组织在前中后三部分中无明显差异,也无功能分区的现象。成体中肾组织中除大量成熟肾单位外,还发现少量发生中的肾单位和少量解体中的肾单位。成熟肾单位的肾小体为典型的淡水真骨鱼类肾小体,肾小管分化为第一近端小管(PⅠ)、第二近端小管(PⅡ)和远端小管(D)。PⅠ、PⅡ段上皮为单层柱状上皮,上皮细胞管腔游离面具有丰富的刷状缘和9 2式纤毛。D段为单层矮柱状上皮或单层立方上皮,管腔游离面无刷状缘,也无纤毛。输尿管前、后段组织结构有明显差异。膀胱为不发达的输尿管膀胱。斯坦尼斯小体2枚。     

中华鳖肾脏的组织化学特性研究

利用光镜组织化学反应对中华鳖肾单位的结构和组织化学特性进行了详细的观察和分析。结果表明,中华鳖肾脏为分叶形的实质器官,肾小叶由被膜和实质组成,实质无髓质和皮质之分,但可以区分为外侧区和内侧区。外侧区嗜酸性,主要分布有近端小管和集合管。内侧区呈弱嗜酸性,肾小体、颈段、中间段和远端小管主要分布在内侧区。肾小球PAS反应呈阳性,但其琥珀酸脱氢酶(SDH)弱阳性,碱性磷酸酶(ALPase)、Na+/K+-ATPase和阿利新兰(AB)反应为阴性。足细胞酸性磷酸酶(ACPase)反应呈阳性。近端小管刷状缘嗜伊红,PAS反应以及ALPase、ACPase和Na+/K+-ATPase酶反应呈阳性,而SDH弱阳性。中间段、远端小管、集合管弱嗜酸性,SDH阳性。中间段Na+/K+-ATPase弱阳性。远端小管细胞侧面呈PAS阳性,腔面显示AB阳性。集合管胞质含有许多ACPase阳性颗粒,腔面呈PAS强阳性,AB阳性。甲苯胺兰(TB)染色可见集合管腔面有阳性颗粒,肾小管上皮含有亮、暗两种细胞。上述组化反应和分布结果表明,鳖的肾小管细胞类型较多,近端小管在原尿的重吸收中起主要作用,远端小管和集合管具有分泌黏液作用。中华鳖肾单位的结构与组化特性不仅与哺乳类和鸟类有一定差异,也与其他爬行动物不完全相同。       

Localization of thyroxine 5'-monodeiodinase activity in the renal proximal tubules in rabbits and rats

To determine the localization of T4 5'-monodeiodinase activity in rabbit and rat nephron segments, the formation of tri-iodothyronine (T3) from thyroxine (T4) was measured in kidney homogenate and in isolated nephron segments obtained by the microdissection method. In order of decreasing activity, homogenates of rabbit renal cortex, outer medulla and inner medulla were capable of converting T4 to T3. In the isolated nephron segments of the rabbit cortex, the activities were noted in both proximal convoluted and proximal straight tubules. On the other hand, the activities were not detected in segments including the cortical thick ascending limb of Henle's loop, the distal convoluted tubule, the connecting tubule, and the cortical collecting tubule. It is concluded that both the convoluted and the straight tubules are the sites of T3 production in the kidney.     

Comparison of the distribution of tissue kallikrein and esterase A, a kallikrein-like enzyme, in rat kidney using specific monoclonal antibodies

Tissue kallikrein (E.C. 3.4.21.35) and arginine esterase A, another closely related, kinin-generating serine protease, have been localized by immunocytochemistry in rat kidney, using monoclonal antibodies that do not crossreact with other kallikrein-related enzymes or with tonin. Kallikrein was present primarily in the apical cytoplasm of the connecting tubule and the cortical collecting duct. Esterase A, on the other hand, was present primarily in the basolateral region of both proximal and distal straight tubules in the outer medulla and medullary rays. In addition, esterase A was demonstrable in distal convoluted tubules and, to a lesser extent, in proximal convoluted tubules. The presence of different kinin-generating enzymes at these sites would permit the formation of kinins from appropriate substrates on both the vascular and luminal poles of separate segments of the kidney tubule.     

Carbonic anhydrase in the monkey kidney

The distribution of carbonic anhydrase in the kidney of the cynomolgus monkey was studied by the histochemical method of Hansson. Glomeruli and Bowman's capsule were inactive. Convoluted proximal tubules showed high enzyme activity at the brush border and the basolateral membranes and the cytoplasm. Straight proximal tubules were less intensely stained. In nephrons with long loops of Henle, the descending thin limb contained weak enzyme activity, whereas the ascending thin limb was inactive. The thick limb of Henle's loop displayed most enzyme activity at the luminal cell border. In distal convoluted tubules enzyme activity was restricted to the basal part of the cells. In the late distal tubule, intercalated cells appeared among the "ordinary" distal cells and contained abundant cytoplasmic enzyme. Many intensely stained intercalated cells were also found in the cortical and outer medullary segments of the collecting duct, intermingled with more weakly stained chief cells. In the inner medullary segment of the collecting duct, enzyme activity gradually disappeared. Many capillaries were clearly stained for enzyme activity. The capillary staining apparently varied with that of the kidney tubules; virtually all capillaries in the cortex, but very few in the inner medulla, were stained. The distribution of carbonic anhydrase in the kidney tubules of the monkey is very similar to that in man and in the rat, but the primate kidney differs from the rat kidney by the presence of capillary enzyme activity. The functional importance of this difference is not clear at present.     

Expression and function of arginine-producing and consuming-enzymes in the kidney

The kidney plays a key role in arginine metabolism. Arginine production is controlled by argininosuccinate synthetase (ASS) and argininosuccinate lyase (ASL) which metabolize citrulline and aspartate to arginine and fumarate whereas arginine consumption is dependent on arginine:glycine amidinotransferase (GAT), which mediates creatine and ornithine synthesis. Histological and biochemical techniques have been used to study the distribution and activity of these enzymes in anatomically dissected segments, in isolated fragments of tubules and in whole tissues. ASS and ASL mRNAs and proteins are expressed in the proximal tubule. Within this nephron segment, the proximal convoluted tubule has a higher arginine synthesis capacity than the proximal straight tubules. Furthermore, this arginine-synthesizing portion of the nephron matches perfectly with the site of citrulline reabsorption from the glomerular filtrate. The kidney itself can produce citrulline from methylated arginine, but this capacity is limited. Therefore, intestinal citrulline synthesis is required for renal arginine production. Although the proximal convoluted tubule also expresses a significant amount of GAT, only 10% of renal arginine synthesis is metabolized to guanidinoacetic acid, possibly because GAT has a mitochondrial localization. Kidney arginase (AII) is expressed in the cortical and outer medullary proximal straight tubules and does not degrade significant amounts of newly synthesized arginine. The data presented in this review identify the proximal convoluted tubule as the main site of endogenous arginine biosynthesis.     

Immunocytochemical localization of Na+, K+-ATPase in the rat kidney

To determine if rat kidney Na+, K+-ATPase can be localized by immunoperoxidase staining after fixation and embedding, we prepared rabbit antiserum to purified lamb kidney medulla Na+, K+-ATPase. When sodium dodecylsulfate polyacrylamide electrophoretic gels of purified lamb kidney Na+, K+-ATPase and rat kidney microsomes were treated with antiserum (1:200), followed by [125I]-Protein A and autoradiography, the rat kidney microsomes showed a prominent radioactive band coincident with the alpha-subunit of the purified lamb kidney enzyme and a fainter radioactive band which corresponded to the beta-subunit. When the Na+, K+-ATPase antiserum was used for immunoperoxidase staining of paraffin and plastic sections of rat kidney fixed with Bouin's, glutaraldehyde, or paraformaldehyde, intense immunoreactive staining was present in the distal convoluted tubules, subcapsular collecting tubules, thick ascending limb of the loops of Henle, and papillary collecting ducts. Proximal convoluted tubules stained faintly, and the thin portions of the loops of Henle, straight descending portions of proximal tubules, and outer medullary collecting ducts did not stain. Staining was confined to basolateral surfaces of tubular epithelial cells. No staining was obtained with preimmune serum or primary antiserum absorbed with purified lamb kidney Na+, K+-ATPase, or with osmium tetroxide postfixation. We conclude that the basolateral membranes of the distal convoluted tubules and ascending thick limb of the loops of Henle are the major sites of immunoreactive Na+, K+-ATPase concentration in the rat kidney.     

Immunohistological demonstration of pyruvate kinase isoenzyme type L in rat with monoclonal antibodies.

Four monoclonal antibodies (MAb) specific for the L-type isoenzyme of rat pyruvate kinase (L-PK) were produced and characterized. They detect at least two different epitopes of the isoenzyme, as shown in interference binding assay and Western blot analysis after peptide mapping. The MAb were used in immunohistology to demonstrate the L-PK isoenzyme in paraffin-embedded normal rat tissues. L-PK was found only in hepatocytes, kidney proximal tubules, islet cells of pancreas, and epithelial cells of the villi of small intestine. The content of L-PK in hepatocytes was often lower in the periportal areas as compared with the periveneous zone. In kidneys a clearcut difference in L-PK content and distribution existed between male and female rats. Male animals possessed more L-PK in the kidney cortex than females. The L-PK content in the inner cortical zone (straight proximal tubules) was higher than in the outer cortical zone (convoluted proximal tubules) in kidneys of males. In contrast, female rats displayed less L-PK in the inner than in the outer cortical zone of the kidneys. Only some of them exhibited the same amount of the isoenzyme in both parts of the kidney proximal tubules.     

Morphometric study of the ultrastructure of nephrons and collecting tubules in the kidney of rats with renal and spontaneous hypertension.

The convoluted proximal and straight distal tubules and the medullary collecting ducts in kidneys of rats with ischaemic renal hypertension and with genetic spontaneous hypertension were studied by means of electron microscopic morphometry. The volume of mitochondria, the area of their cristae, of the outer surface and of membranes of the intercellular labyrinth, and other ultrastructural characterisitcs were calculated. No significant differences were found in proximal tubules between experimental and control animals, although in the distal tubules in both experiments the coefficient characterizing the level of morphologic organization of mitochondria, which takes into account their basic morphometric parameters, was reduced in hypertensive animals as compared with the intact ones. The volume of mitochondria and the area of their cristae in collecting ducts, and also the area of membranes of the intercellular labyrinth were increased. Our results suggest that in hypertension the reabsorption of substances from the proximal tubules is essentially normal, that it is reduced at the beginning of the distal tubules but is intensified in the collecting ducts.     

Carbonic anhydrase activity in kidney and lower intestine of the European starling

A histochemical investigation of kidney and lower intestine of the European starling (Sturnus vulgaris) shows no carbonic anhydrase activity in proximal convoluted tubules, although activity is seen in similarly prepared sections of rat proximal tubules. Early distal tubule cells in the starling are stained throughout the cytoplasm and at the apical and highly infolded basolateral membranes. Late distal tubules lose apical activity and have reduced basolateral infolding, resulting in less intense staining. Darkly stained intercalated cells appear in the connecting tubules and cortical collecting ducts. Both of these segments also show intense basolateral staining. Medullary cones of the starling are highly organized, with central zones containing unstained thin descending limbs of loops of Henle, surrounded by both medullary collecting ducts with only scattered cells staining for enzyme, and by thick ascending limb segments. The latter contain many uniformly stained cells intermingled with occasional unstained cells. Scattered cells of the starling colonic villi demonstrate intense apical brush border membrane staining as well as cytoplasmic staining. Cells lining the cloaca stain less intensely. A biochemical assay for carbonic anhydrase was used to quantify enzyme activity in these tissues. Starling kidney contained 1.96 ± 0.33 (mean ± SEM) enzyme units/mg protein, less than half the activity seen in rat kidney. Stripped colonic epithelium contained 0.66 ± 0.15 enzyme units/mg protein. These quantitative results correlate well with the interpretations derived from the histochemical observations. The lack of proximal tubule carbonic anhydrase activity suggests that the avian kidney relies more on distal nephron segments to achieve net acidification of the urine.     

The cellular localization of increased atrial natriuretic peptide mRNA and immunoreactivity in diabetic rat kidneys.

Increased intrarenal atrial natriuretic peptide (ANP) mRNA expression has been reported in several disorders. To further investigate the action of renal ANP, we need to elucidate the exact site of its alteration in diseased kidneys. ANP mRNA and ANP were detected by in situ hybridization and immunohistochemistry in the kidneys from five normal and five diabetic rats. Renal ANP mRNA in eight normal and nine diabetic rats was measured by RT-PCR with Southern blot hybridization. In normal and diabetic rats, the distribution of ANP mRNA and ANP-like peptide was mainly located in proximal, distal, and collecting tubules. However, diabetic rats had significant enhancement of ANP mRNA and ANP-immunoreactive staining in the proximal straight tubules, medullary thick ascending limbs, and medullary collecting ducts. ANP mRNA in the outer and inner medulla of nine diabetic rats increased 5.5-fold and 3.5-fold, but only 1.8-fold in the renal cortex. This preliminary study showed that ANP mRNA and ANP immunoreactivity in proximal straight tubules, medullary thick ascending limb, and medullary collecting ducts apparently increased in diabetic kidneys. These findings imply that ANP synthesis in these nephrons may involve in adaptations of renal function in diabetes.     

Enhancement of gentamicin-induced nephrotoxicity by Mg deficiency in non-pregnant rats. Morphological, enzyme histochemical and immunohistochemical studies

Non-pregnant rats fed an Mg-deficient diet showed some degenerated and calcified proximal tubules in the inner region of the medullary rays accompanied by reduced or absent enzyme activities. After gentamicin treatment some damaged convoluted proximal tubules occurred. Enzyme histochemistry revealed decreased activities for brush border and lysosomal hydrolases; using immunohistochemistry lesions were detectable for the cytoskeletal proteins keratin and vimentin. Administration of gentamicin to Mg-deficient rats led to a further decrease of hydrolase activities in obviously intact proximal tubules and drastic structural and enzymatic defects as well as alterations of the cytoskeletal proteins in the convoluted and straight segments of other proximal tubules and to a lesser degree also in glomeruli and further portions of the tubular apparatus including the collecting ducts.