Histology and Ultrastructure of the Nephron and Kidney Interstitial Cells in the Atlantic Salmon (Salmo salar Linnaeus 1758) at Different Stages of Life Cycle.

This article presents data on the mesonephros histology and ultrastructure in the Atlantic salmon from the Baltic Sea and Barents Sea populations, with an emphasis on comparisons between the following ontogenetic stages: parr, smolting, adult life at sea, the adults' return to their natal river to spawn, and spawning. The ultrastructural changes in the renal corpuscle and cells of the proximal tubules of the nephron occurred as early as the smolting stage. Such changes reflect fundamental alterations during the pre-adaptation to life in saltwater. In the Barents Sea population, the adult salmon sampled in the sea had the smallest diameters of the renal corpuscle and proximal and distal tubules, the most narrow urinary space, and the thickest basement membrane. In the group of salmon that entered the mouth of the river and spent less than 24 h in freshwater, the structural rearrangements occurred only in the distal tubules. Better development of the smooth endoplasmic reticulum and a greater abundance of mitochondria in the tubule cells were observed in the adult salmon from the Barents Sea compared to those from the Baltic Sea. Cell-immunity activation was initiated during the parr-smolt transformation. Another pronounced innate-immunity response was registered in the adults returning to the river to spawn.

Age-related glomerular histogenesis in inbred indigenous rabbit (Oryctolagus cuniculus): A morphological, morphometrical, and immunohistochemical study with emphasis on Lgr5-positive cells.

Although the regeneration of renal glomeruli and nephrons after injuries especially in adult mammals is not possible, understanding normal glomerular histogenesis is important. Here, we sought to study the morphometrical and histological development of the normal renal glomeruli of rabbits from birth until postnatal day 40. Moreover, we immunohistochemically evaluated the extent and rate of the Lgr5 expression in the immature renal stem/progenitor cells. The untreated, clinically healthy inbred indigenous rabbits (from Duhok city of Iraqi Kurdistan) were sacrificed at postnatal days 1, 10, 15, 30, and 40. After being processed and embedded in paraffin, rabbit anti-human Lgr5 as a primary antibody and rabbit ImmunoCruz LSAB as a staining kit were used for the immunohistochemical detection of Lgr5+ve cells. For normal histology, hematoxylin and eosin were used. The peak generation and regression of renal corpuscles were at postnatal days 10, and 40, respectively, with 50% decrease. The glomeruli diameter significantly increased (1.3-fold, p = 0.001), whereas the Bowman's space diameter decreased (50%, p < 0.0001) from postnatal day 1-40. The immature nephrons were seen only in one-day postnatal rabbits. While the superficial glomeruli were compact and small, the juxtamedullary glomeruli were larger and segmented. The formation and development of the juxtaglomerular apparatus were documented at postnatal days 30 and 40 only. Our data revealed highly expressed Lgr5 protein at postnatal day one, and the expression level decreased gradually with advancing age. It was moderately expressed on day 10 and mildly expressed on day 15, whereas no expression was recorded on days 30 and 40 postnatally. Our study provides evidence that the Lgr5 gene, within multipotent stem cells and their lineage progeny, was activated within newly formed glomeruli throughout the early postnatal stages of nephrogenesis.

Delineation of the healthy rabbit kidney by immunohistochemistry - A technical note.

Pre-clinical animal models are needed to investigate and study kidney injuries and diseases. The rabbit kidney model is frequently used because various important parameters can be assessed with it. For example, histology and immunohistochemistry are indispensable as tissue morphology and composition can be investigated qualitatively as well as quantitatively. Here, different histological and immunohistochemical stainings were performed in the rabbit healthy naïve kidney tissue. First, overnight formalin fixation followed by paraffin embedding and cryopreservation with a subsequent 10-minute formalin fixation prior to staining were compared. Cryosections showed a more pronounced staining pattern, with clear borders at low magnifications, but blurred borders at higher magnifications. Then, antigen retrieval (AR) for paraffin embedded sections resulted in more prominent corresponding signals compared to stainings without AR. Moreover, several advantages and disadvantages of chromogenic versus immunofluorescence stainings were considered. Chromogenic staining was advantageous compared to immunofluorescence for collagen I and III, and to a minor degree for fibronectin. Finally, distinct structures, such as the pelvis, the calices, the glomeruli and tubuli, were stained in serial sections with diverse immunohistochemical stainings in order to delineate their composition. The following stainings were performed: standard Haematoxylin&Eosin and Elastica van Gieson staining, collagen I, collagen III, fibronectin, α-SMA, ki-67 and protease-activated receptor-2 (PAR-2). While chromogenic stainings of collagen I and collagen III were particularly useful to depict kidney structures in paraffin sections compared with cryosections, cryosections immunofluorescently stained for α-SMA were superior to paraffin sections, particularly at higher magnifications. With regard to specific structures, we found renal vessel walls positive for fibronectin and α-SMA, while the Bowman's capsule was only positive for fibronectin and α-SMA showed only tiny spots. The mesangial cells of the glomeruli and the distal tubuli were PAR-2 positive, while the proximal tubuli were PAR-2 negative.

Histomorphological changes in the pancreas and kidney and histopathological changes in the liver in male Wistar rats on antiretroviral therapy and melatonin treatment.

Combination antiretroviral therapy (cART) has shown to cause inflammation, cellular injury and oxidative stress, whereas melatonin has been successful in reducing these effects. The aim of the study was to determine potential morphometric changes caused by cART in combination with melatonin supplementation in human immunodeficiency virus (HIV)-free rats. Tissue samples (N = 40) of the pancreas, liver and kidney from a control (C/ART-/M-), cART group (C/ART + ), melatonin (C/M + ) and experimental group (ART+/M + ) were collected and stained with haematoxylin and eosin (H&E) and evaluated for histopathology. The pancreata were labelled with anti-insulin and anti-glucagon to determine α- and ß-cell regions. Kidneys were stained with periodic acid Schiff (PAS) to measure the area, perimeter, diameter and radius of renal corpuscles, glomeruli and proximal convoluted tubules (PCTs). Blood tests were conducted to determine hepatotoxicity. No significant changes in histopathology were seen. Melatonin stimulated pancreatic islet abundance, as the number of islets per mm2 was significantly higher in the C/M+ than in the C/ART-/M- and ART+/M+. Parameters of the renal corpuscle, glomeruli, renal space and PCTs were significantly lower in the C/ART+ compared to the other groups, thus cART may have caused tubular dysfunction or cellular damage. A significant increase in serum haemoglobin was observed in the C/ART+ compared to the C/ART-, which showed cART increases serum haemoglobin in the absence of immune deficiency. Serum lipids were significantly decreased in the C/M+ compared to the C/ART-, possibly due to the effect of melatonin on the decrease of lipolysis, decreasing effect on cholesterol absorption and stimulation of lipoprotein lipase (LPL) activity. In conclusion, we have demonstrated that melatonin stimulated α-cell production, increased the number of pancreatic islets and caused a decrease in total lipids, whereas cART increased serum haemoglobin and decreased various parameters of the nephron in an HIV-free rat model, suggestive of tubular dysfunction.

Insights into kidney stem cell development and regeneration using zebrafish.

Kidney disease is an escalating global health problem, for which the formulation of therapeutic approaches using stem cells has received increasing research attention. The complexity of kidney anatomy and function, which includes the diversity of renal cell types, poses formidable challenges in the identification of methods to generate replacement structures. Recent work using the zebrafish has revealed their high capacity to regenerate the integral working units of the kidney, known as nephrons, following acute injury. Here, we discuss these findings and explore the ways that zebrafish can be further utilized to gain a deeper molecular appreciation of renal stem cell biology, which may uncover important clues for regenerative medicine.

The development of a virtual 3D model of the renal corpuscle from serial histological sections for E-learning environments.

Histology is a core subject in the anatomical sciences where learners are challenged to interpret two-dimensional (2D) information (gained from histological sections) to extrapolate and understand the three-dimensional (3D) morphology of cells, tissues, and organs. In gross anatomical education 3D models and learning tools have been associated with improved learning outcomes, but similar tools have not been created for histology education to visualize complex cellular structure-function relationships. This study outlines steps in creating a virtual 3D model of the renal corpuscle from serial, semi-thin, histological sections obtained from epoxy resin-embedded kidney tissue. The virtual renal corpuscle model was generated by digital segmentation to identify: Bowman's capsule, nuclei of epithelial cells in the parietal capsule, afferent arteriole, efferent arteriole, proximal convoluted tubule, distal convoluted tubule, glomerular capillaries, podocyte nuclei, nuclei of extraglomerular mesangial cells, nuclei of epithelial cells of the macula densa in the distal convoluted tubule. In addition to the imported images of the original sections the software generates, and allows for visualization of, images of virtual sections generated in any desired orientation, thus serving as a "virtual microtome". These sections can be viewed separately or with the 3D model in transparency. This approach allows for the development of interactive e-learning tools designed to enhance histology education of microscopic structures with complex cellular interrelationships. Future studies will focus on testing the efficacy of interactive virtual 3D models for histology education.

Using zebrafish to study podocyte genesis during kidney development and regeneration.

During development, vertebrates form a progression of up to three different kidneys that are comprised of functional units termed nephrons. Nephron composition is highly conserved across species, and an increasing appreciation of the similarities between zebrafish and mammalian nephron cell types has positioned the zebrafish as a relevant genetic system for nephrogenesis studies. A key component of the nephron blood filter is a specialized epithelial cell known as the podocyte. Podocyte research is of the utmost importance as a vast majority of renal diseases initiate with the dysfunction or loss of podocytes, resulting in a condition known as proteinuria that causes nephron degeneration and eventually leads to kidney failure. Understanding how podocytes develop during organogenesis may elucidate new ways to promote nephron health by stimulating podocyte replacement in kidney disease patients. In this review, we discuss how the zebrafish model can be used to study kidney development, and how zebrafish research has provided new insights into podocyte lineage specification and differentiation. Further, we discuss the recent discovery of podocyte regeneration in adult zebrafish, and explore how continued basic research using zebrafish can provide important knowledge about podocyte genesis in embryonic and adult environments. genesis 52:771-792, 2014. © 2014 Wiley Periodicals, Inc.

Renal corpuscles were protected from dichlorvos: induced morphological alterations in rats by antioxidant vitamins / Protección de corpúsculos renales ante alteraciones morfológicas inducidas por el diclorvos en ratas mediante el uso de vitaminas antioxidantes

Dichlorvos (DDVP), an organophosphorus pesticide is a volatile compound which enters the human body through oral, dermal and inhalational routes and is excreted via the kidney. This study assessed the effects of DDVP on the histology of the kidney. Twenty five male rats (75.05 ± 5.55 g) were divided into 5 groups of 5 rats per group as follows: Unexposed group, exposure to DDVP alone for 5 weeks, and 3 other groups exposed to DDVP for 5 weeks in addition to supplement with Vitamin E, vitamin C, and red palm oil (RPO). Rats were exposed to DDVP in poorly ventilated cardboard cages for 4 hours daily. On completion of exposure, rats were euthanized and tissue processed by routine paraffin wax method and stained with H&E. Morphological alterations monitored by histological and morphometric studies using the graticule and software packages. Data were analyzed with ANOVA and p<0.05 considered as significant. DDVP caused significant reduction (10%) in the maximum glomerular diameter and 18% reduction in the maximum width of the renal corpuscle when compared with unexposed rats. However, VTE, VTC, and RPO significantly elevated the maximum glomerular diameter by 21%, 22%, 23% the respectively. Similarly, VTE, VTC, and RPO significantly elevated the maximum width of the renal corpuscle by 17%, 19%, 20% respectfully. Glomerular tuft cellularity was neither affected by DDVP treatment nor by vitamin augmentation. Inhaled DDVP caused histological alterations in the microscopic anatomy of renal corpuscles of rat which was mitigated by vitamin supplementation. Data suggest involvement of prolonged DDVP use in the aetiology of renal failure.

El diclorvos (DDVP), un pesticidas organofosforado, es un compuesto volátil que entra en el cuerpo humano a través de la vía oral, dérmica y por rutas inhalación, excretándose por vía renal. Este estudio evaluó los efectos histológicos del DDVP sobre el riñón. Veinticinco ratas machos (75,05±5,55 g) se dividieron en 5 grupos de 5 ratas cada uno: grupo no expuesto, expuesto a DDVP durante 5 semanas, y otros 3 grupos expuestos a DDVP durante 5 semanas, suplementados con vitamina E (VTE), vitamina C (VTC) y aceite de palma roja (APR). Las ratas fueron expuestas a DDVP en jaulas de cartón con poca ventilación por 4 horas diarias. Al término de la exposición, las ratas se sacrificaron y el tejido fue procesado para inclusión en parafina y tinción con H&E. Las alteraciones morfológicas se evaluaron mediante estudios histológicos y morfométricos utilizando retículas y software. Los datos se analizaron con la prueba ANOVA considerado un p<0,05 como significativo. El DDVP causó una reducción significativa (10%) en el diámetro máximo glomerular y ancho máximo del copúsculo renal (18%), en comparación con las ratas no expuestas. Sin embargo, el diámetro máximo glomerular fue significativamente elevado con VTE, VTC y APR en 21%, 22% y 23%, respectivamente, así como para el ancho máximo del corpúsculo renal por 17%, 19% y 20%, respectivamente. La celularidad de la red glomerular no fue afectada por el DDVP ni aumentó con el tratamiento de vitamina. El DDVP inhalado provocó alteraciones histológicas en la anatomía microscópica de los corpúsculos renales de rata, las que fueron mitigadas por la suplementación de vitamina. Los datos sugieren relación entre la exposición prolongada a DDVP y la etiología de la insuficiencia renal.

Expression pattern of zinc-finger transcription factor Odd-skipped related 2 in murine development and neonatal stage.

The Odd-skipped gene, first identified as a Drosophila pair-rule zinc-finger transcription factor, plays an important role in Drosophila development. The mammalian homolog, Odd-skipped related 2 (Osr2), regulates limb, tooth, and kidney development in mouse embryos. However, the detailed expression pattern of Osr2 during neonatal development remains unclear. In this study, we investigated Osr2 expression patterns in mouse neonatal and embryo tissues using qPCR and in situ hybridization methods. First, we examined the tissue distribution of Osr2 by qPCR, and found it to be highly expressed in the uterus and moderately in the testes, small intestine, and prostate. That expression was also found in eye, kidney, placenta, lung, thymus, lymph node, stomach, and skeletal muscle tissues, and in all embryonic stages. On the other hand, Osr2 was not expressed in brain, heart, liver, or spleen samples. Next, we examined the tissue localization of Osr2 using in situ hybridization. Osr2 was found in the craniofacial region on E13.5, with notable expression in dental germ mesenchyme as well as the renal corpuscle on E17.5. As for neonatal tissues, Osr2 was expressed in the dental papilla, dental follicle, Harderian gland, nasal bone, eyelid dermis, synovial joint, and tibial subcutis. Our findings suggest that Osr2 functions in reproductive system organs, such as the uterus, testes, prostate, placenta, and ovaries. Furthermore, based on its expression in kidney, Harderian gland, eyelid dermis, and tibial subcutis tissues, this transcription factor may be involved in hormone synthesis and function. Together, our results demonstrate the role of Osr2 in postnatal development and embryogenesis.

Chronic intrauterine exposure to endotoxin does not alter fetal nephron number or glomerular size.

A reduced nephron endowment early in life adversely impacts on long-term functional reserve in the kidney. A recent study has shown that acute exposure to chorioamnionitis during late gestation can adversely impact on nephrogenesis. The present study aimed to examine the effects of chronic, low-dose endotoxin exposure in utero, during the period of nephrogenesis, on nephron number and glomerular size in preterm lambs. Ewes were administered either endotoxin (lipopolysaccharide; 1 mg/day) or saline at 110-133 days of gestation (term approximately 147 days) via surgically implanted osmotic minipumps within the amniotic cavity. The ewes were induced to deliver preterm at 133 days gestation and the kidneys of the lambs were analysed at 8 weeks after term-equivalent age. Nephron number per kidney was determined using a combined optical disector and fractionator stereological approach; renal corpuscle size was also measured stereologically. At 8 weeks after term-equivalent age there was no significant effect of in utero exposure to endotoxin on bodyweight or kidney weight and there were no significant differences in nephron number, nephron density or renal corpuscle volume between groups. We conclude that chronic intrauterine inflammation during the period of nephrogenesis may not adversely impact on the number of nephrons formed within the kidney or on the volume of the renal corpuscle.

Role of Apoptosis in the Differentiation of the Parietal Epithelium of the Renal Corpuscle in the Developing Rat Kidney / 대한해부학회지

The purpose of this study was to establish the role of apoptosis in the developing renal corpuscle in the prenatal rat kidney. Kidneys from 14-, 16-, 18-, and 20-day-old fetuses[E-14, E-16, E-18, and E-20] were preserved by immersion or perfusion via the heart using Bouin`s fixative. Apoptosis was detected`by in situ nick end labeling method using ApopTag kit. In kidneys from E-14, apoptotic cells and bodies were found only in the mesenchymal tissue surrounding the developing nephrons. In kidneys from E-16, E-18, and E-20, apoptotic cells and bodies were located mainly in the columnar distal epithelium of the renal vesicle[future parietal epithelium] as well as in the parietal epithelium of the renal corpuscles of S-shaped bodies, stage III and IV nephrons. Apoptosis was not observed in the proximal part of renal vesicles or in the podocytes in renal corpuscles. In contrast, strong bel-2 immunoreactivity was present in the proximal part of the renal vesicle and in podocytes in S-shaped bodies, but gradually decreased in stage III and IV nephrons. The distal part of the renal vesicle had weak staining for bcl-2, and there was no bel-2 immunoreactivity in the parietal epithelium of S-shaped bodies, and stage III and IV nephrons. We conclude that bcl-2 is involved in the regulation of apoptosis during the differen-tiation of the parietal epithelium of Bowmann`s capsule.

Effect of long-term administration of somatostatin analogue on renal enlargement in uninephrectomized-diabetic rats

Recent study has demonstrated that the long-acting somatostatin analogue administration effectively prevented initial renal growth in diabetic and uninephrectomized rats. In the present study we examined long-term effect of somatostatin analogue (Sandostatin) on renal enlargement in uninephrectomized-diabetic rat5. Animals were divided into 4 groups: (1) normal control rats (C) (n = 7), (2) uninephrectomized rats (NPX) (n = 7), (3) uninephrectomized-diabetic rats (NPX + DM) (n = 7) and (4) NPX + DM rats treated with Sandostatin (NPX + DM + Tx) (n = 9). All animals had free access to diet (50% protein) and water during the experimental period. To the NPX + DM + Tx rats, 2.5 micrograms of Sandostatin was given subcutaneously twice a day for 8 weeks. Periodic observations were done at 0, 4 and 8 weeks. After 8 weeks. NPX rats (0.540 +/- 0.017 (SEM)) had higher fractional kidney weights (FKW) (wet kidney wt/body wt) compared to C rats (0.410 +/- 0.014) (p < 0.0005), and both NPX + DM rats (0.983 +/- 0.098) and NPX + DM + Tx rats (1.091 +/- 0.042) had higher FKW compared to C rats (p < 0.0001) and NPX rats (p < 0.005), respectively. But no significant change of FKW was observed between NPX + DM rats and NPX + DM + Tx rats. Systolic blood pressure, BUN, serum creatinine, glomerular filtration rate and 24 hour urine protein excretion in NPX + DM rats were not different from those in NPX + DM + Tx rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural Study on the Renal Corpuscle after Removal of Ureteral Obstruction in Rabbit / 대한비뇨기과학회지

This study was designed to clarify morphological changes in the renal corpuscles of the experimental rabbit kidney after unilateral ureteral obstruction and release of Unilateral ureteral obstruction through a light and electro microscopy. It was further aimed at obtaining data, esp. of electron microscopy, concerning the morphological repair after relieving ureteral obstruction. A total of 25 white rabbits, weighing 2.5kg, were used. 25 rabbits were divided into three groups-normal control, unilateral ureteral obstruction, release of unilateral obstruction. The normal! control group consisted of 5 rabbits. The remaining 20 rabbits were completely ligated in the left ureter with silk threads. Ten obstructed kidneys were studied by light and electron microscopy, five of them two weeks after obstruction, and the remaining five four weeks after obstruction. A total of ten postobstructed kidneys, five of which were reoperated by Mackinnon method for the relief of ureteral obstruction two weeks after obstruction and the remaining five four weeks after obstruction. They were studied for light and electron microscopy 15 days after relieving ureteral obstruction. Specimens of renal cortex from experimental animals were fixed in 10% neutral formalin or Bouin's solution, embedded in paraffin wax, sectioned at a thickness of 5 um, and stained with hematoxylin-eosin, periodic acid-schiff reaction or Masson's trichome for light microscopy. For electron microscopy, the tissues were fixed in a mixture of 2% paraformaldehyde and 2.5ao glutaraldehyde (phosphate buffer, pH 7.2) prior to fixation in 1% osmium tetroxide (phosphate buffer, pH 7.2) and then embedded in Epon 812. The sections were cut with LKB- III ultramicrotome and contrasted with uranyl acetate and lead citrate and examined with electron microscopy JEM 100B. The results of this study were as follows: 1. The abnormal morphology of the glomerulus in kidneys obstructed for four weeks showed: Slight glomerular congestion, capillary dilatation, no changes in endothelium, podocyte and microstructures. 2. Deformity of Bowman's capsular epithelium such as irregular basal invaginations facing with the basal lamina was observed in the two week obstructed kidneys, and severe degenerative changes such as desquamated capsular epithelial cells in the Bowman's space and long basal cytoplasmic processes embedded in the basal lamina in the four week obstructed kidneys. 3. Among the postobstructed kidney, the two week obstructed kidneys were restored to near normal on the 15th day, but in the four week obstructed kidney, Bowman's capsular epithelium showed partial recovery. 4. The results indicate that glomeruli in the renal corpuscle were preserved until four week weeks after ureteral obstruction but Bowman's epithelium showed change in the 2nd week after obstruction and severe degenerative changes of Bowman's capsular epithelium were noticed in the 4th week after ureteral obstruction. The morphological changes were totally restored in the group where ureteral obstruction was relieved after two weeks, but in the group which was relieved of ureteral obstruction after four weeks the morphological repairs were prolonged until after 15 days.

STUDY ON PROLIFERATION AND APOPTOSIS IN DEVELOPING RENAL CORPUSCLES OF MOUSE / 解剖学报

Objective To study cell proliferation and apoptosis of renal corpuscle in normal developing mouse.Methods PCNA immunohistochemisty method,terminal deoxynucleotidyl transferase mediated dUTP-biotin nick endlabeling(TUNEL staining method)and light,electron microscopy were used to observe proliferation and apoptosis within corpuscle at different stages of development.Results Nearly all cells in Ⅰ and Ⅱ stages had nuclear PCNA immunolabeling.The number of PCNA immunolabeling cells during Ⅲ and Ⅳ stages was gradually decreased,and to less in Ⅴ stage.TUNEL positive cells could be easily observed before birth and identified in Ⅲ and Ⅳ stages.Electron microscope revealed that the mitotic activity was observed in all cells of Ⅰ and Ⅱ stages renal corpuscles.The mitotic phases of endothelial cells and podocytes could be seen in Ⅲ stage,but only endothelial mitotic activities in Ⅳ stage of renal corpuscle.Apoptotic activities of endothelial cell and Bowman's parietal cell were noted,predominantly in Ⅲ and Ⅳ stages.Conclusion Proliferation and apoptosis exist universally in the course of developing renal corpuscle,and supervise and control the regular development of renal corpuscle cooperatively.

STUDY ON APOPTOSIS IN DEVELOPING RENAL CORPUSCLES OF MOUSE / 解剖学报

Objective To study apoptosis and morphological characteristics in the developing renal corpuscles of mouse kidney. Methods Light,transmission electron microscope and TUNEL technique were used to observe apoptosis in the developing renal corpuscles of different embryonic and postnatal mice. Results Apoptotic cells could be found when renal corpuscles occurred at embryonic day 14(E14).It peaked around E18 and decreased thereafter.Electron microscope revealed that apoptotic cells had morphological characteristics such as margination of condensed nuclear chromatin,shrinking cytoplasm.Apoptosis of endothelial cells and podocytes were more frequent.Two results of apoptotic cells were observed,1. being ingested by neighboring cells; 2. apoptotic cells were dropping into glomerular capillary lumens or Bowman capsules.Conclusion Apoptotic cells were found in all the time during the development of mouse renal corpuscles.It might play an important role in the development of renal corpuscles.