Partial Unilateral Ureteral Obstruction Research Articles

Renoprotective effect of diacerein in rats with partial unilateral ureteral obstruction model

Abstract Objectives We aimed to analyze the effects of diacerein in a rat model of partial unilateral ureteral obstruction (PUUO). Methods We randomly divided 24 female rats into three groups. Control group, PUUO group and PUUO + diacerein group. The PUUO group was subjected to the PUUO model for seven days. The PUUO + diacerein group received oral diacerein (80 mg/kg) for seven days. Spectrophotometric methods were employed to measure oxidative stress parameters, including malondialdehyde (MDA), protein carbonyl (PC) and antioxidant enzyme levels, including glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD), while indicators of renal function, such as kidney injury molecule-1 (KIM-1) and neutrophil gelatinous-associated lipocalin (NGAL), along with inflammatory parameters interleukin-1 beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6), were assessed using the ELISA method. Inflammatory parameters were measured in blood samples, and other parameters were analyzed in kidney tissue. Hematoxylin-eosin method examinations were used for histological analyses. Results IL-1beta, TNF-alpha, and IL-6 levels were found to be significantly decreased in the PUUO + diacerein group compared to the PUUO group (p=0.006, p=0.002 and p=0.001, respectively). In the PUUO + diacerein group, GSH-Px and SOD activities increased compared with the PUUO group (p=0.031 and p=0.037, respectively). We also observed a significant improvement in renal function parameters, such as KIM-1 and NGAL levels in the PUUO + diacerein group compared to PUUO (p=0.002 and p=0.012, respectively). The PC and MDA levels were highest in the PUUO group (p<0.001). Similarly, the histopathologic tissue damage was the most prominent PUUO group (p<0.001). Conclusions Our study found that diacerein is a highly effective pharmacologic agent in alleviating oxidative damage in PUUO model rats.

The Inhibition of Fibrosis and Inflammation in Obstructive Kidney Injury via the miR-122-5p/SOX2 Axis Using USC-Exos.

Background: Fibrosis and inflammation due to ureteropelvic junction obstruction substantially contributes to poor renal function. Urine-derived stem-cell-derived exosomes (USC-Exos) have therapeutic effects through paracrine. Methods: Invitro, the effects of USC-Exos on the biological functions of HK-2 and human umbilical vein endothelial cells were tested. Cell inflammation and fibrosis were induced by transforming growth factor-β1 and interleukin-1β, and their anti-inflammatory and antifibrotic effects were observed after exogenous addition of USC-Exos. Through high-throughput sequencing of microRNA in USC-Exos, the pathways and key microRNAs were selected. Then, the antifibrotic and anti-inflammatory effects of exosomal miR-122-5p and target genes were verified. The role of the miR-122-5p/SOX2 axis in anti-inflammatory and antifibrotic effects was verified. Invivo, a rabbit model of partial unilateral ureteral obstruction (PUUO) was established. Magnetic resonance imaging recorded the volume of the renal pelvis after modeling, and renal tissue was pathologically analyzed. Results: We examined the role of USC-Exos and their miR-122-5p content in obstructive kidney injury. These Exos exhibit antifibrotic and anti-inflammatory activities. SOX2 is the hub gene in PUUO and negatively related to renal function. We confirmed the binding relationship between miR-122-5p and SOX2. The anti-inflammatory and antifibrotic effects of miR-122-5p were inhibited, indicating that miR-122-5p has anti-inflammatory and antifibrotic effects by inhibiting SOX2 expression. Invivo, the PUUO group showed typical obstructive kidney injury after modeling. After USC-Exo treatment, the shape of the renal pelvis shown a remarkable improvement, and inflammation and fibrosis decreased. Conclusions: We confirmed that miR-122-5p from USC-Exos targeting SOX2 is a new molecular target for postoperative recovery treatment of obstructive kidney injury.

The Rho-kinase inhibitor Y27632 promotes ureteral relaxation in an in vivo rat model for partial ureteral obstruction.

Aim of this study was to evaluate the effect of intravenous Y27632 (a ROK inhibitor) on intra-ureteral pressures and on blood pressure in an in vivo rat model for unilateral partial ureteral obstruction (PUO). 15 Male Sprague Dawley rats were used. Under isofluran anesthesia, saline was continuously infused via polyethylene (PE)-10 catheters inserted in the ureters beneath the kidney pelvis. Left psoas muscle was sutured around the distal left ureter to create a partial obstruction. Carotid artery and femoral vein were cannulated with PE catheters for registration of mean arterial blood pressure (MAP) and for administration of drugs. Left and right ureter pressures and MAP were simultaneously recorded. Y27632 (0.03 and 0.1mg/kg each n = 6-7) was given intravenously. T-test was used for comparisons. Spontaneous peristaltic pressure waves were recorded at baseline for both ureters. After the obstruction, Y27632 reduced maximum pressure (MaxP) by 10.5 ± 1.9% (0.03mg/kg; p = 0.004) and 29.1 ± 4.8% (0.1mg/kg; p < 0.001), minimum pressure (MinP) by 5.2 ± 2.3% (0.03mg/kg; p = 0.02) and 12.2 ± 3.4% (0.1mg/kg; p = 0.009), the area under the curve (AUC) by 7.8 ± 2.4% (0.03mg/kg; p = 0.008) and 16.5 ± 3.7% (0.1mg/kg;p = 0.007), the waves amplitude by 23.4 ± 11.3% (0.03mg/kg; p = 0.098) and 38.7 ± 7.5% (0.1mg/kg; p < 0.001), with no effect on contraction frequency. During simultaneous recordings from the normal ureter at the investigated doses, Y27632 reduced MaxP, MinP, AUC and waves amplitude by 1-7%. The MAP was reduced by 12.5 ± 5.3% (0.03mg/kg; p = 0.07) and 15.8 ± 1.8% (0.1mg/kg; p < 0.001). Y27632 decreased intra-ureteral pressures of a partially obstructed ureter with limited effect on blood pressure in an animal model of unilateral PUO.

Nicorandil and Bone Marrow-derived Mesenchymal Stem Cells Therapeutic Effect after Ureteral Obstruction in Adult Male Albino Rats.

Chronic kidney disease is a global health problem for which renal fibrogenesis is the final treatment target. In our work, we have highlighted two new strategies, nicorandil and Bone marrow-derived mesenchymal stem cells (BM-MSCs), as effective in reversing renal fibrosis induced by partial unilateral ureteral obstruction (PUUO). The current study included 96 male albino rats randomly divided into four groups, with 24 rats per group; Group I, the control group; Group II, PUUO, where two-thirds of the left ureter was entrenched in the psoas muscle; Group III, same surgical procedure as in Group II for 7 days, and then the rats received 15 mg/kg/day nicorandil once daily for 21 days; and Group IV, same surgical procedure as in Group II for 7 days, and then rats were given 3 × 106 of labeled MSCs injected intravenous, and left for 21 days. Blood and kidney tissues were collected for biochemical, histological, and molecular analyses. Both the nicorandil and BM-MSCs treatment groups could ameliorate kidney damage evidenced by inhibition of MDA elevation and total antioxidant capacity reduction caused by PUUO. Also, there was a significant reduction observed in TNF, TGF, IL6, collagen I, and α-SMA in addition to improvement in histological examination. However, a significant difference was found between the BM-MSCs and nicorandil-treated groups. Our results suggest that BM-MSCs and nicorandil improved renal fibrosis progression through their antiapoptotic, anti-inflammatory, and antifibrotic effects in male albino rats subjected to PUUO, with BM-MSCs being more effective compared to nicorandil.

Evaluation of Diuretic Renal Doppler Ultrasonography Findings in Chronic Unilateral Partial Ureteral Obstruction in Rabbits

Evaluation of Diuretic Renal Doppler Ultrasonography Findings in Chronic Unilateral Partial Ureteral Obstruction in Rabbits

Abstract 090: Cells Of The Renin Lineage Promote Kidney Regeneration Post - Release Of Ureteral Obstruction In Neonatal Mice.

Renin, the rate-limiting enzyme of the renin-angiotensin system, is increased in the kidneys subjected to ureteral obstruction. We elucidated the changes and contribution of renin-producing cells (RPCs) and the cells of renin lineage (CoRL) during kidney damage and regeneration using a partial unilateral ureteral obstruction (pUUO) model in neonatal mice. Renin cells were ablated by cell-specific expression of diphtheria toxin A chain (DTA) and labeled with GFP. We compared the cell fate changes between kidneys from the wild-type (WT) and the DTA-expressing animals, using the pUUO model. The kidneys of 3W old DTA-positive Ren1 dDTA/+ ;R26R DTA/+ and Ren1 dCre/+ ;R26R DTA/+ genotypes were grossly normal. We observed no significant differences in the Myh11-positive renal vascular area between the WT and the DTA-positive mice (WT-3W: 1.72±0.10 % (n=6), Ren1 dDTA/+ ;R26R DTA/+ -3W: 1.94 ±0.123 % (n=7), Ren1 dCre/+ ;R26R DTA/+ -3W: 2.017±0.16% (n=4)). In the kidneys of the WT group, RPCs and the CoRL significantly increased at 3W post-obstruction and the distribution was similar to the sham-operated kidneys at 2W post-relief of obstruction (Renin-positive area-WT: Sham-3W: 0.57±0.02% (n=6), Obstructed-3W: 1.59±0.44% (n=4), Post-release-2W: 0.71±0.12% (n=3)). There was a significant decrease in RPCs in the DTA animals, and the reduction of RPCs and CoRL was markedly higher in Ren1 dCre/+ ;R26R DTA/+ mice in comparison to Ren1 dDTA/+ ;R26R DTA/+ group. Also, the DTA-positive animals did not respond to pUUO with a significant increase in renin as in the WT (Renin-positive area: Ren1 dDTA/+ ;R26R DTA/+ Sham-3W: 0.13±0.048% (n=5), Obstructed-3W: 0.23±0.10% (n=5), Post-release-2W: 0.14±0.04% (n=9) Ren1 dCre/+ ;R26R DTA/+ Sham: 0.010±0.004% (n=4), Obstructed: 0.07±0.004% (n=4), Post-release: 0.03±0.004% (n=3)). The renal fibrotic area and Tgfb1 mRNA levels post-obstruction and relief of obstruction were significantly high in Ren1 dCre/+ ;R26R DTA/+ group in comparison to Ren1 dDTA/+ ;R26R DTA/+ genotype due to the depletion of CoRL. Thus, our current study reveals that CoRL undergoes cell fate changes in response to obstruction and the release of obstruction, and these changes play a critical role in promoting kidney regeneration post-relief of obstruction.

Evaluation of acute partial unilateral ureteral obstruction based on the renal venous impedance index in Rabbit: An experimental study

To investigate the feasibility of the venous impedance index (VII) in the diagnosis of acute partial unilateral ureteral obstruction (APUUO), in this study we aimed to measure and compare changes in intrarenal venous flow and arterial flow. In New Zealand rabbits (n=10) the left ureter was narrowed by ligation. Doppler ultrasonographic (US) examination of the interlobar arteries and veins in both kidneys was performed preoperatively and 3, 6, 12, 24, and 48 h after ureteral ligation. Resistive index (RI), RI difference (RIΔ) and the RI ratio (RIr), and the VII difference (VIIΔ) were calculated from RI and VII obtained from the obstructive and nonobstructive kidneys. The RI and VII were postoperatively compared between the left and right kidneys. Although the mean RI for obstructive kidneys was higher than those for nonobstructive kidneys, the difference was only statistically significant at 3 and 24 h (P=0.007, and P=0.049, respectively). In all postoperative measurement times, RIΔ was ≥0.08 and RIr was ≥1.169, and the mean VII values were significantly lower in the obstructive kidneys than the nonobstructive kidneys (P≤0.002), and the VIIΔ was equal to or greather than 0.159. The venous flow was more affected than arterial flow in the obstructive kidney. The renal RI alone was insufficient as a diagnostic criterion. The renal VIIΔ ≥0.16 can be enhanced the diagnostic accuracy of in APUUO if used as a combination of the RIΔ≥0.08 and RIr≥1.1.

Abstract MP25: Defining The Role Of Renin Lineage Cells During Regeneration After Release Of Partial Ureteral Obstruction In Neonatal Mice.

Our previous study on a partial unilateral ureteral obstruction (pUUO) model in neonatal mice showed that the release of obstruction halts the progression of kidney damage and leads to a remarkable repair of the kidney with improvement in renal blood flow. In the current study, we aim to understand the role of mural cells of the renin lineage during kidney damage and repair in the neonatal pUUO model. Our results show a marked increase in renin-positive areas in kidneys obstructed for 3W (Sham-3W: 0.70±0.10%, n=3; Obstructed-3W: 1.82±0.43%, n=3). However, relief of obstruction at 1W restored the renin-positive areas to sham levels (Post-release-2W: 0.70±0.09%; n=3). Lineage tracing using Ren1 d Cre;mTmG mice revealed a significant increase in GFP+ cells in the obstructed kidneys, with a decrease post-release. To understand further the dynamic changes in cells of renin lineage due to obstruction, we ablated the renin cells using DTA (Diphtheria toxin subunit A). We crossed the DTA fl/fl mice with Ren1 d -DTA het ;Ren1 d Cre;mTmG mice and performed pUUO in the resultant pups with DTA in the renin cells (DTA+). DTA+ animals showed thinning of the renal vasculature and a 90% reduction in renin-positive area compared to controls [Control: 0.70±0.10% (n=3); DTA+: 0.06±0.03% (n=3)]. In addition, there was no significant increase in the renin-positive area post-obstruction [Sham-3W: 0.06±0.04% (n=3); Obstructed-3W: 0.12±0.05% (n=4); Post-release-2W: 0.08±0.03% (n=4)]. These results indicate that ablation of renin cells abolished the obstruction-mediated surge in the renin expression. However, measurement of interstitial collagen positive area indicated that despite the absence of renin cells, the fibrotic damage due to obstruction recovered remarkably post-release [Collagen positive area: Sham-3W: 3.38±0.67% (n=3) Obstructed-3W: 62.98±31.50% (n=3); Post-release-2W: 10.93±5.46% (n=4)]. Similarly, vascular damage induced by persistent obstruction and recovery following the relief of obstruction was similar between the DTA+ and non-DTA animals. Our results imply that though the renin and renin lineage cells increase in obstructed kidneys, ablation of renin cells does not affect the regeneration capacity of kidneys following the relief of obstruction.

Evaluation of pheniramine maleate and zofenopril in reducing renal damage induced by unilateral ureter obstruction. An experimental study.

IntroductionObstruction of the ureter may occur due to congenital, iatrogenic or other reasons. This can cause hydronephrosis in the early stage and can lead to cellular inflammation, necrosis and atrophy in the kidney tissue. The aim of this paper is to evaluate the protective effect of pheniramine maleate (PM) and zofenopril on renal damage caused by hydronephrosis due to unilateral partial ureter obstruction.Material and methodsTwenty-four female Sprague Dawley rats were divided into 4 groups. Group 1: sham group, group 2: partial unilateral ureteral obstruction (PUUO) group, group 3: PUUO + PM group, group 4: PUUO + zofenopril group. Paraoxonase (PON), total antioxidant status (TAS) and total oxidant status (TOS) of tissue and blood samples were measured and calculated. Tissue samples were evaluated histopathologically.ResultsAn increase in tissue TAS and a decrease in tissue TOS and OSI levels were detected in groups 3 and 4 compared to group 2 (both: p < 0.01). Tissue PON levels showed an increase in groups 3 and 4 compared to groups 1 and 2 (both: p < 0.01). Histopathological evaluation showed a decrease in interstitial inflammation and congestion in groups 3 and 4 compared to the control group (p < 0.001). The decrease was observed to be more significant in group 4 compared to group 3 (p < 0.01).ConclusionsIn our experimental study, we observed that PM and zofenopril reduce the oxidation and tissue damage caused by unilateral partial obstruction.

Expression of Acsm2, a kidney-specific gene, parallels the function and maturation of proximal tubular cells

The acyl-CoA synthetase medium-chain family member 2 (Acsm2) gene was first identified and cloned by our group as a kidney-specific "KS" gene. However, its expression pattern and function remain to be clarified. In the present study, we found that the Acsm2 gene was expressed specifically and at a high level in normal adult kidneys. Expression of Acsm2 in kidneys followed a maturational pattern: it was low in newborn mice and increased with kidney development and maturation. In situ hybridization and immunohistochemistry revealed that Acsm2 was expressed specifically in proximal tubular cells of adult kidneys. Data from the Encyclopedia of DNA Elements database revealed that the Acsm2 gene locus in the mouse has specific histone modifications related to the active transcription of the gene exclusively in kidney cells. Following acute kidney injury, partial unilateral ureteral obstruction, and chronic kidney diseases, expression of Acsm2 in the proximal tubules was significantly decreased. In human samples, the expression pattern of ACSM2A, a homolog of mouse Acsm2, was similar to that in mice, and its expression decreased with several types of renal injuries. These results indicate that the expression of Acsm2 parallels the structural and functional maturation of proximal tubular cells. Downregulation of its expression in several models of kidney disease suggests that Acms2 may serve as a novel marker of proximal tubular injury and/or dysfunction.

Urinary Cytochrome C and Caspase-3 as Novel Biomarker of Renal Function Impairment in Unilateral Ureteropelvic Junction Obstruction Model of Wistar Rats.

IntroductionProlonged obstruction in UPJO would lead to kidney destruction. It is important to find a non-invasive biomarker for early detection of renal impairment before definitive treatment for UPJO. In this study, we aim to evaluate the role of urinary cytochrome c and caspase-3 as a novel biomarker to predict renal function impairment in a UPJO model in Wistar rats.MethodsTwenty-five male Wistar rats were separated into 3 groups. Group I consists of 5 rats without any treatment or model, group II consists of 5 rats (sham group), and group III consists of 15 rats with the unilateral partial ureteral obstruction model. After 4, 15, and 21 days of observation, the urine was collected and rats were sacrificed to collect the glomerular count in the kidney. Measurement of cytochrome c and caspase-3 was done using the ELISA method, while the glomerular count was done using a light microscope. Data were analyzed using factorial repeated measures ANOVA test and correlation test with Pearson and processed using SPSS version 20.0.ResultsThe UPJO group has a significant increase in cytochrome c concentration and caspase-3 concentration compared to the control group and sham group (p<0.05). There was a significant decrease in the normal glomerulus count of the UPJO group (p<0.05). There was a significant relationship between the decrease in glomerulus count with the concentration of cytochrome c and caspase-3 in the UPJO group.ConclusionThere was a significant relationship between the decrease in glomerulus count with the increase in the concentration of cytochrome c and caspase-3 in the UPJO group.

The effect of coenzyme Q and selenium on kidney in rats with partial unilateral ureteral obstruction.

In this study, we aimed to investigate the antioxidant effects of selenium and coenzyme Q on renal damage in a partial unilateral ureteral obstruction (PUUO) in a rat model. A total of 24 Sprague-Dawley rats were divided into four groups as Group 1 Control Group, Group 2, PUUO Group, Group 3 PUUO + coenzyme Q group, Group 4 PUUO + selenium group. Paraoxonase (PON), total antioxidant capacity (TAC), and total oxidant levels (TOS) were analyzed biochemically from tissue and blood samples. Tissue samples were examined histopathologically. The TAC in the tissues was found to be statistically significantly increased in Groups 3 and 4, compared to Group 2. Tissue TOS was found to be significantly reduced in Groups 3 and 4, compared to Group 2. Serum PON levels were significantly increased in Group 3 and 4, compared to Group 1 and 2. Histopathological examination showed that interstitial inflammation and congestion were lesser in the coenzyme Q and selenium groups than in the PUUO group. A more significant decrease was found in the selenium group than in the coenzyme Q group. Our study results showed that coenzyme Q and selenium reduced the oxidation and the damage in tissue in PUUO in rats.

Protective effects of ghrelin on kidney tissue in rats with partial ureteral obstruction

Background/aim The aim was to investigate the protective and therapeutic effects of ghrelin, which has antioxidant and antiinflammatory activity, on preventing kidney damage that occurs by induced partial ureteral obstruction in rats.Materials and methods Twenty-eight adult male rats were included in the study, and the rats were divided into 4 groups. After the laparotomy operation on the sham group, the ureter was identified in the retroperitoneal area and was duly sutured (n = 7). Ghrelin was administered for seven days intraperitoneally, and after the nephrectomy performed on the 15th day, the rats were sacrificed (n = 7). A partial ureteral obstruction was performed after the laparotomy on the PUO group. The rats were sacrificed after the nephrectomy operation performed on the 15th day (n = 7). A partial ureteral obstruction was formed after the laparotomy followed by seven days of waiting in the PUO + ghrelin group. Ghrelin was given in the dose of 10 ng/kg per day intraperitoneally for the next 7 days, and the rats were sacrificed after the nephrectomy operation performed on the 15th day (n = 7). All groups were evaluated for histological damage and catalase, superoxide dismutase, total glutathione, malondialdehyde, and myeloperoxidase levels were measured in the same tissues.Results When the 2nd group and the sham group were compared histologically, it was observed that the damage had increased by a statistically significant level in the partial ureteral obstruction group (P = 0.001). When the group which was ghrelin-treated after the partial ureteral obstruction was compared to the group with just partial ureteral obstruction, the histopathological changes were found to decrease significantly in that group (P = 0.001). While the statistical significance of the levels of CAT, GSH, and MPO enzymes was detected among biochemical changes in the 2nd group when compared to the sham group (P < 0.01), the 3rd group showed a statistically significant difference in the levels of SOD and GSH enzymes compared to the 4th group (P < 0.05).Conclusion Ghrelin administration to rats after the formation of an experimental partial unilateral ureteral obstruction reduces tissue damage due to ghrelin’s antiinflammatory and antioxidant effects. Ghrelin administration may prevent tissue damage biochemically and histopathologically in obstructive uropathy cases.

Positive outcomes of phosphodiesterase type 5 inhibitor on histopathologic and biochemical changes induced by ureteral obstruction.

We examined the effects of tadalafil, one of the phosphodiesterase type 5 (PDE5) inhibitors, in a rat model of with partial and complete unilateral ureteral obstruction (UUO). The rats were divided into 5 groups: sham (n=6), partial unilateral ureteral obstruction (PUUO, n=6), PUUO with tadalafil treatment (PUUO+T; Cialis, 10 mg/72 h, intragastric; Lilly, Indianapolis, Indiana, USA), complete unilateral ureteral obstruction (CUUO, n=6), and CUUO with tadalafil treatment (CUUO+T). Fifteen days after the UUO, the ureter presented changes in the layers of urothelium and significant infiltration of inflammatory cells in the PUUO and CUUO groups. Compared with the sham, PUUO and CUUO groups had severe increased inflammatory cell infiltration. The urothelial epithelium exhibited cell degeneration and loss because of the swollen, atrophic, and denuded epithelial cells in the PUUO and CUUO groups. In the PUUO+T and CUUO+T groups, the urothelium revealed less epithelial cell degeneration and loss.The expressions of α-smooth muscle actin (α-SMA) and transforming growth factor-β (TGF-β) exhibited up-regulation in the PUUO and CUUO groups. The expression of TGF-β decreased positively correlated with that of α-SMA in the tadalafil therapy groups, PUUO+T and CUUO+T. The phosphodiesterase type 5 inhibitor's tadalafil reduced expressions of α-SMA and TGF-β in the obstructed ureters, measured by biochemical examinations. In addition, tadalafil decreased urothelium degeneration due to the decreased epithelial cell loss and inflammatory cell infiltration. Our results show that tadalafil prevents or slows down the onset of ureter inflammation and urothelial degeneration in rats with UUO.

Changes in cell fate determine the regenerative and functional capacity of the developing kidney before and after release of obstruction.

Congenital obstructive nephropathy is a major cause of chronic kidney disease (CKD) in children. The contribution of changes in the identity of renal cells to the pathology of obstructive nephropathy is poorly understood. Using a partial unilateral ureteral obstruction (pUUO) model in genetically modified neonatal mice, we traced the fate of cells derived from the renal stroma, cap mesenchyme, ureteric bud (UB) epithelium, and podocytes using Foxd1Cre, Six2Cre, HoxB7Cre, and Podocyte.Cre mice respectively, crossed with double fluorescent reporter (membrane-targetted tandem dimer Tomato (mT)/membrane-targetted GFP (mG)) mice. Persistent obstruction leads to a significant loss of tubular epithelium, rarefaction of the renal vasculature, and decreased renal blood flow (RBF). In addition, Forkhead Box D1 (Foxd1)-derived pericytes significantly expanded in the interstitial space, acquiring a myofibroblast phenotype. Degeneration of Sine Oculis Homeobox Homolog 2 (Six2) and HoxB7-derived cells resulted in significant loss of glomeruli, nephron tubules, and collecting ducts. Surgical release of obstruction resulted in striking regeneration of tubules, arterioles, interstitium accompanied by an increase in blood flow to the level of sham animals. Contralateral kidneys with remarkable compensatory response to kidney injury showed an increase in density of arteriolar branches. Deciphering the mechanisms involved in kidney repair and regeneration post relief of obstruction has potential therapeutic implications for infants and children and the growing number of adults suffering from CKD.

Protein kinase C inhibitor chelerythrine attenuates partial unilateral ureteral obstruction induced kidney injury in neonatal rats

The present study aimed to evaluate the renoprotective effects of chelerythrine (CHE), a protein kinase C inhibitor, on neonatal rats after partial unilateral ureteral obstruction (UUO) surgery. New born Sprague Dawley rats were subjected to partial UUO 48 h after birth and received a daily intraperitoneal injection of 5 mg/kg CHE. At 21-day age, the rats were scarified and the kidneys were collected for analysis. Results showed that CHE treatment significantly increased kidney weight and restored renal function in the obstructed kidney. Histological examination demonstrated that CHE attenuated renal injury by reducing renal parenchymal loss and preventing glomerular and tubular degeneration. In addition, CHE inhibited partial UUO-induced upregulated kidney injury molecule-1 expression and apoptosis and renal fibrosis. Moreover, as a PKC inhibitor, CHE significantly inhibited PKCα and PKCβ membrane translocation. This action may be associated with its effects of anti-apoptosis and anti-fibrosis and contribute to the renoprotection. This short-term study suggests that CHE is beneficial for obstructive nephropathy in neonatal rats and provides foundation for further studies to reveal the long-term effects of CHE on obstructive nephropathy in children and infants.

Comparison of renal interstitial fibrosis induced by different animal models of urinary tract infection

Objectives: To identify a better animal model that more closely mimics early renal interstitial fibrosis induced by long-term recurrent urinary tract infection (UTI), as occurs in humans, three different murine models were compared. Methods: Three different murine models of upper UTI were established, including direct injection of bacteria into renal tissues, ascending urinary infection with partial unilateral ureteric obstruction, and repeated infusion of bacteria into the bladder. The histopathology of the kidneys was assessed by hematoxylin and eosin staining. Masson's trichrome staining and immunohistochemistry for α-smooth muscle actin (α-SMA) expression were used for the detection of fibrosis. Results: All three models developed different levels of inflammation in the kidney. However, in contrast to the severe renal interstitial fibrosis in the other two models, the model of repeated infusion of bacteria into the bladder demonstrated early renal interstitial fibrosis by Masson's trichrome staining and immunohistochemistry for α-SMA. Conclusions: The model of repeated infusion of bacteria into the bladder developed low levels of renal interstitial fibrosis, which resembles the early tissue damage in the kidney induced by recurrent UTI s in humans. This model may therefore offer a better way to study the early therapeutic intervention of renal interstitial fibrosis caused by inflammation.

Renal parenchyma impairment characterization in partial unilateral ureteral obstruction in mice with intravoxel incoherent motion-MRI.

Ureteropelvic junction obstruction constitutes a major cause of progressive pediatric renal disease. The biological mechanisms underlying the renal response to obstruction can be investigated using a clinically relevant mouse model of partial unilateral ureteral obstruction (pUUO). Renal function and kidney morphology data can be evaluated using renal ultrasound, scintigraphy and uro-magnetic resonance imaging (uro-MRI), but these methods are poorly linked to histological change and not all are quantitative. Here, we propose to investigate pUUO for the first time using an intravoxel incoherent motion diffusion sequence. The aim of this study was to quantitatively characterize impairment of the kidney parenchyma in the pUUO model. This quantitative MRI method was able to assess the perfusion and microstructure of the kidney without requiring the injection of a contrast agent. The results suggest that a perfusion fraction (f) reduction is associated with a decrease in the volume of the renal parenchyma, which could be related to decreased renal vascularization. The latter may occur before impairment by fibrosis and the findings are in accordance with the literature using the UUO mice model and, more specifically, on pUUO. Further investigation is required before this technique can be made available for the diagnosis and management of children with antenatal hydronephrosis and to select the optimal timing of surgery if required.

Evaluation of renal metabolic response to partial ureteral obstruction with hyperpolarized 13 C MRI.

Hyperpolarized 13 C magnetic resonance imaging (MRI) may be used to non-invasively image the transport and chemical conversion of 13 C-labeled compounds in vivo. In this study, we utilize hyperpolarized 13 C MRI to evaluate metabolic markers in the kidneys longitudinally in a mouse model of partial unilateral ureteral obstruction (pUUO). Partial obstruction was surgically induced in the left ureter of nine adult mice, leaving the right ureter as a control. 1 H and hyperpolarized [1-13 C]pyruvate MRI of the kidneys was performed 2days prior to surgery (baseline) and at 3, 7 and 14days post-surgery. Images were evaluated for changes in renal pelvis volume, pyruvate, lactate and the lactate to pyruvate ratio. After 14days, mice were sacrificed and immunohistological staining of both kidneys for collagen fibrosis (picrosirius red) and macrophage infiltration (F4/80) was performed. Statistical analysis was performed using a linear mixed effects model. Significant kidney × time interaction effects were observed for both lactate and pyruvate, indicating that these markers changed differently between time points for the obstructed and unobstructed kidneys. Both kidneys showed an increase in the lactate to pyruvate ratio after obstruction, suggesting a shift towards glycolytic metabolism. These changes were accompanied by marked hydronephrosis, fibrosis and macrophage infiltration in the obstructed kidney, but not in the unobstructed kidney. Our results show that pUUO is associated with increased pyruvate to lactate metabolism in both kidneys, with injury and inflammation specific to the obstructed kidney. The work also demonstrates the feasibility of the use of hyperpolarized 13 C MRI to study metabolism in renal disease.

38 - Attenuation of partial unilateral ureteral obstruction-induced renal damage with hyperbaric oxygen therapy in a rat model

ABSTRACT Objective: The objective of the present study was to evaluate the effectiveness of HBO therapy on biochemical parameters, renal morphology and renal scintigraphy in rats undergoing chronic unilateral partial ureteral obstruction (UPUO). Material and methods: Thirty-five rats were divided into five equal groups: Control group; Sham group; HBO group; UPUO group and UPUO/HBO group. The effects of HBO therapy were examined using biochemical parameters and histopathological changes. After calculating the score for each histopathological change, the total histopathological score was obtained by adding all the scores. In addition, dynamic renal scintigraphy findings were evaluated. Results: Serum parameters indicating inflammation, serum tumor necrosis factor- alpha, ischemia modified-albumin, IMA/albumin ratio and Pentraxin-3 levels, were observed to be high in the UPUO group and low in the UPUO/HBO treatment group. Similarly, in the treatment group, the reduction in malondialdehyde, total oxidant status and oxidative stress index levels and increase in total antioxidant capacity values were observed to be statistically significant compared to the UPUO group (p<0.001, p=0.007, p<0.001, p=0.001, respectively). The total score and apoptosis index significantly decreased after administration of HBO treatment. Dynamic 99mTc-MAG3 renal scintigraphy also showed convincing evidence regarding the protective nature of HBO against kidney injury. In the UPUO/HBO therapy group, the percentage contribution of each operated kidney increased significantly compared to the UPUO group (41.73% versus 32.72%). Conclusion: The findings of this study indicate that HBO therapy had a reno-protective effect by reducing inflammation and oxidative stress, and preserving renal function after renal tissue damage due to induction of UPUO.