氟伐他汀对5/6肾切除大鼠肾脏皮质细胞外基质积聚的影响

目的观察降脂药氟伐他汀对5/6肾切除大鼠肾皮质细胞外基质(ECM)积聚的影响和探讨其降脂作用外的肾脏保护机制。方法将5/6肾切除大鼠随机分为模型组和氟伐他汀治疗组(治疗组),另设假手术组作为对照。实验期间测定尿蛋白排泄率;氟伐他汀处理(7mg·kg-1·d-1)13周后免疫组化法检测肾小球Ⅳ型胶原(ColⅣ)及纤连蛋白(FN)蛋白表达;酶谱法检测肾皮质基质金属蛋白酶(MMP)-2活性;免疫印迹检测金属蛋白酶组织抑制物(TIMP)-2蛋白表达。结果与假手术组相比,模型组大鼠尿蛋白排泄、肾小球Ⅳ型胶原和FN表达均明显增加(均为P<0.01)。模型组大鼠肾皮质MMP-2活性较假手术组明显降低(P<0.01),而TIMP-2蛋白表达明显上调(P<0.01)。氟伐他汀治疗后这些改变均明显好转。结论氟伐他汀可能通过增加5/6肾切除大鼠肾脏MMP-2活性和降低TIMP-2表达,从而能增加细胞外基质降解和减轻肾小球细胞外基质积聚。     

羟苯磺酸钙对5／6肾切除大鼠肾脏微血管的保护机制

目的探讨羟苯磺酸钙对5／6肾切除大鼠肾脏微血管的保护作用及其机制。方法复制5／6肾切除大鼠模型，设5／6肾切除模型组和羟苯磺酸钙干预组，在二次手术后第1、2、4、8、12周观察各组大鼠肾功能及残肾组织病理改变。采用免疫组化观察肾脏Ang-1和CD31表达的变化，RT-PCR观察肾脏Ang-1 mRNA的表达并行相关性分析。结果与同时点模型组比较，羟苯磺酸钙干预组大鼠尿蛋白减少、肾功能改善、残肾组织病理改变明显减轻。自第2周开始Ang-1 mRNA及蛋白表达水平升高，其后期的下调趋势变缓、CD31表达增强、肾脏微血管病变显著改善。结论羟苯磺酸钙可能通过增强Ang-1早期的上调幅度并延缓后期的下调来改善5／6。肾切除大鼠肾脏的微血管病变，从而保护肾脏。     

Effects of delayed treatment with enalapril and/or lovastatin on the progression of glomerulosclerosis in 5/6 nephrectomized rats

To evaluate the effect of delayed treatment with enalapril orlovastatin on the progression of glomerulosclerosis and to examineif the combined treatment with enalapril and lovastatin showsynergistic effect, a total of 31 Sprague-Dawley rats were studiedfor 16 weeks following 5/6 nephrectomy (NPX). Treatment wasdelayed until 8 weeks after NPX. In untreated control rats (n=8), sustained systemic hypertensionwith increasing proteinuria, serum cholesterol, triglyceride,BUN and widespread glomerulosclerosis and mesangial expansionwere observed. Treatment with enalapril alone (R, n=8) reversed systemic hypertension,prevented a further increase in proteinuria, and significantlyreduced glomerulosclerosis relative to the control group. Treatment with lovastatin alone (L, n=7) also reduced glomerulosclerosisand serum cholesterol compared to the controls. The drug alsoprevented a further increase in proteinuria and systemic bloodpressure although the difference from the control rats did notreach statistical significance. Treatment with both enalapril and lovastatin (RL, n=8) almostcompletely prevented glomerulosclerosis and significantly reducedmesangial expansion, systemic blood pressure, serum cholesterol,and proteinuria compared to controls. Only the combined treatmentstabilized BUN and reduced mesangial expansion compared to controlR, or L groups. Conclusion. Delayed treatment with enalapril or lovastatin iseffective in preventing the progression of glomerulosclerosis,and combined treatment appears to show synergistic effect in5/6 nephrectomized rat model.     

The influence of mutant lactobacilli on serum creatinine and urea nitrogen concentrations and renal pathology in 5/6 nephrectomized rats

Objectives: To explore the capacity of mutant lactobacilli to remove creatinine (Cr) and urea nitrogen (UN) via the gastrointestinal tract and its effects on renal pathology in the 5/6 nephrectomized rat model of chronic renal failure.

Methods: Sixty Sprague–Dawley rats were randomly divided into a Sham group, a Model group, a wide-type Lactobacilli group (L.B group), and a Mutant Lactobacilli group (Mut-L.B group). The rats in the Model, LB and Mut-L.B groups underwent 5/6 nephrectomy. Eight weeks after administration, 24-h urine, orbital blood and digestive secretions were collected to analyze Cr and UN levels. Pathological changes in nephridial tissues were observed by hematoxylin and eosin and Masson trichrome staining, and the expression of TGF-β1 and FN was detected by immunohistochemistry.

Results: There were no significant differences in urinary Cr and UN levels among the Sham, L.B and Mut-L.B groups (p?>?.05), while serum and digestive Cr and UN levels were significantly decreased in the Mut-L.B group (p?<?.01). Furthermore, renal tubular injury and interstitial fibrosis were significantly reduced and TGF-β1 and FN expression was decreased (p?<?.05) in the Mut-L.B group.

Conclusion: Mutant lactobacilli decreased serum Cr and UN levels, reduced the expression of TGF-β1 and FN in renal tissues and alleviated renal interstitial injury and fibrosis in a rat model of chronic renal failure in a mechanism that may involve decomposition and not just excretion of small molecule toxins in the gastrointestinal tract.     

Combined effects of moderately elevated blood glucose and locally produced TGF-beta1 on glomerular morphology and renal collagen production.

BACKGROUND: There is a correlation between renal graft rejection and blood glucose (BG) levels. Furthermore, diabetic patients may develop non-diabetic renal diseases, which in some circumstances progress rapidly. Since transforming growth factor-beta1 (TGF-beta) levels are elevated in many renal diseases, the accelerated progression may be due to interactions between glucose and locally produced TGF-beta1. Therefore, we investigated the effect of mild hyperglycaemia on glomerular morphology and collagen production in TGF-beta1 transgenic mice. METHODS: To achieve BG concentrations of approximately 15 mmol/l in TGF-beta1 transgenic and non-transgenic mice, we used multiple streptozotocin (STZ) injections, and after 8 weeks, we measured the changes in glomerular morphology and total collagen content. We also analysed extracellular matrix (ECM) and protease mRNA levels using real-time polymerase chain reaction (PCR) and phosphorylated extracellular signal-regulated kinase 1/2 (pERK) expression by immunohistochemistry. RESULTS: Mild hyperglycaemia alone had no effect on glomerular structure or ECM deposition. Over-expression of TGF-beta1 increased basement membrane thickness (BMT) and the mesangial volume fraction. Furthermore, it augmented ECM, Matrix metalloproteinase-2 (MMP), MMP-9, plasminogen activator inhibitor-1 (PAI) and tissue inhibitor of metalloproteinase-1 (TIMP) gene expression and pERK1/2 immunostaining. Elevated BG in combination with TGF-beta1 resulted in enlargement of glomerular volume, total mesangial volume and renal collagen content. Moreover, high BG exaggerated TGF-beta1-induced changes in the BMT, MMP-2 and TIMP-1 expression and pERK1/2 staining. CONCLUSION: Even moderate elevations in BG accelerate the progression of those kidney diseases in which TGF-beta1 is involved. This emphasizes the importance of strict BG control in renal transplant patients and diabetic patients with renal malfunctions unrelated to diabetes.     

Possible role of nitric oxide in the protective effect of resveratrol in 5/6th nephrectomized rats

BACKGROUND: Nitric oxide (NO) plays an important role in the modulation of glomerular disease. The renal protective effect of resveratrol (RVT), a polyphenolic phytoalexin, was investigated in the 5/6th nephrectomized rats. MATERIALS AND METHODS: Resveratrol (5 mg/kg, PO) was administered for 12 weeks to 5/6th nephrectomized (NX) rats together with and without nitro L-arginine methyl ester (L-NAME) (10 mg/kg, IP). We evaluated the effect of these agents on proteinuria, hypertension, renal function, glomerulosclerosis, and urinary excretion of nitric oxide metabolites. RESULTS: 5/6th NX resulted in elevation in systolic blood pressure (SBP), reduced the urinary excretion of NO metabolites, increased urinary protein excretion, and deranged renal function and glomerulosclerosis. Treatment of animals with resveratrol significantly attenuated the increase in SBP, preserved the normal renal function, reduced the urinary protein excretion, increased the urinary excretion of NO metabolites, and prevented the glomerulosclerosis. Co-administration of animals with L-NAME along with resveratrol prevented the protection observed with resveratrol. CONCLUSION: These findings indicate that resveratrol exerts its protective effect in 5/6 NX rats through a nitric oxide pathway.     

前列腺素E1脂微球载体制剂对5／6肾切除大鼠肾小管上皮细胞转分化的影响

目的观察前列腺素E1脂微球载体制剂（Lipo-PGE1）对5／6肾切除大鼠肾小管上皮细胞-间充质细胞转分化（EMT）的影响。方法将大鼠随机分为假手术组、5／6肾切除模型组（模型组）和Lipo-POE1治疗组。使用Lipo-PGE1干预后第8周处死大鼠测定大鼠尿蛋白及肾功能,光镜观察肾组织病理改变,免疫组织化学法检测肾组织α-平滑肌肌动蛋白（mSMA）的表达。结果模型组大鼠24h尿蛋白排泄量、血尿素氮和血肌酐水平显著高于假手术组,肾小球和肾小管-间质病变显著,肾组织α-SMA表达明显增加;经过Lipo-PGE1治疗后,大鼠24h尿蛋白排泄量较模型组显著减少,肾功能明显改善,肾小球和肾小管-间质病变减轻,肾组织α-SMA表达较模型组显著下调。结论Lipo-PGE1能够显著下调5／6肾切除大鼠肾组织α-SMA表达,抑制肾小管上皮细胞转分化,这可能是其肾脏保护作用机制之一。     

Regulatory effects of inducible nitric oxide synthase on cyclooxygenase-2 and heme oxygenase-1 expression in experimental glomerulonephritis.

BACKGROUND: We explored whether inducible nitric oxide synthase (iNOS) driven nitric oxide (NO) production regulates expression of iNOS, endothelial NOS (eNOS), Cyclooxygenase-2 (COX-2), and Hemeoxygenase-1 (HO-1) proteins in a rat model of glomerulonephritis induced by antibody raised in rabbits against rat glomerular basement membrane (anti-GBM). METHODS: Rats were injected either with non-immune serum (control), or anti-GBM serum. In a group of rats N6-(1-iminoethyl)-L-lysine (L-NIL) was administered prior to injection of anti-GBM serum to inhibit iNOS activity. Urinary nitrite plus nitrate (NOx) excretion was assessed to determine the extent of iNOS inhibition by L-NIL. Urinary albumin excretion was assessed to determine extent of proteinuria. Urinary PGE2 was assessed as a marker of COX activity. Glomeruli were harvested 24 h after injection of anti-GBM serum and ED1, COX-2, iNOS, eNOS and HO-1 expression was analysed by Western blot analysis. RESULTS: iNOS activity in glomeruli was effectively reduced in L-NIL-treated nephritic animals. In these animals, there was exacerbation of proteinuria and reduction in urinary PGE2 levels without changes in the extent of macrophage infiltration in glomeruli. In nephritic animals, there was an increase in glomerular protein levels of COX-2, HO-1 and iNOS, but not of eNOS. While L-NIL treatment reduced glomerular HO-1, levels of COX-2 and iNOS increased; but not that of eNOS. CONCLUSIONS: The observations indicate that in glomerulonephritis iNOS-driven NO production acts as a negative feedback regulator of iNOS itself, suppresses COX-2 levels, and maintains HO-1 levels.     

Role of TGF-beta/GLUT1 axis in susceptibility vs resistance to diabetic glomerulopathy in the Milan rat model.

BACKGROUND: GLUT1 upregulation and increased glucose transport activity may contribute to extracellullar matrix (ECM) accumulation characterizing diabetic nephropathy (DN). Rats of the Milan hypertensive strain (MHS) are resistant to both hypertensive and diabetic renal disease, due to a haemodynamic protection. On the contrary, those of the Milan normotensive strain (MNS) develop spontaneous glomerulosclerosis, and when rendered diabetic, show typical morphological and haemodynamic changes. METHODS: To assess whether susceptibility to diabetic glomerulopathy in MNS rats is associated with higher glucose transporter 1 (GLUT1) expression (and glucose transport activity) vs MHS rats, diabetic and nondiabetic MNS and MHS rats were followed for 6 months and mesangial cells derived from these animals were exposed to high glucose (HG) vs normal glucose (NG) conditions. RESULTS: Glomerular expression of GLUT1 protein and ECM and transforming growth factor-beta (TGF-beta) mRNA was significantly upregulated in diabetic vs nondiabetic MNS, but not MHS rats. Upon exposure to HG and/or TGF-beta, mesangial cells from 1- and 8-month-old MNS rats showed higher glucose transport activity and GLUT1 membrane expression than those from age-matched MHS rats. Likewise, ECM and TGF-beta production increased more markedly in response to HG and/or TGF-beta in MNS vs MHS mesangial cells. CONCLUSIONS: These data indicate that susceptibility to diabetic glomerulopathy in MNS rats is associated with increased GLUT1-dependent glucose transport activity in response to hyperglycaemia and/or TGF-beta, which may amplify ECM overproduction. Conversely, the haemodynamic protection from glomerulosclerosis in MHS rats is associated with lack of upregulation of TGF-beta/GLUT1 axis, thus supporting the concept that this axis may represent the link between haemodynamic and metabolic mechanisms of injury.     

Expression of bone type 1 PTH receptor in rats with chronic renal failure

Some researchers have speculated that a decrease in bone type 1 PTH receptor (PTH1R) may be among the causes of “skeletal resistance” in chronic renal failure (CRF). Indeed, the down-regulation of PTH1R mRNA has been identified in uremic bones. However, few studies have identified the patterns of PTH1R protein expression. In this article we compare the bone expression of PTH1R protein and mRNA under control and CRF conditions. Sprague–Dawley rats underwent 5/6 nephrectomies (Nx) or sham operations (control), and were killed 16 weeks later. Blood urea nitrogen (BUN), serum Cr, P, and parathyroid hormone (PTH) were higher in the Nx group than in the controls, while serum Ca and 1,25(OH)₂D₃ were lower in the Nx group. Immunohistochemical images of lumbar bone samples were analyzed by an image processing system. PTH1R was essentially identified in all osteoblasts. The expression of osteoblast PTH1R protein was quantified based on the gray value of PTH1R staining. The mean gray scale of osteoblasts was 25% lower in Nx rats than in control rats (P < 0.01), whereas osteoblast cell counts and cell sizes were not significantly different between the two groups. Thus, down-regulation of PTH1R protein expression under the CRF condition appeared likely. Total RNA extracted from the bone samples was reverse transcribed for real-time polymerase chain reaction (PCR). PTH1R mRNA expression was 33% lower in the Nx group than in the control group in the quantitative PCR analysis (P < 0.05). Our findings suggested that osteoblast PTH1R expression is down-regulated at both the protein and mRNA levels in the steady state of CRF.     

Tacrolimus restores podocyte injury and stabilizes the expression of Cabin1 in 5/6 nephrectomized rats

Podocyte injury is a vital factor, which induces massive proteinuria. Studies have shown that tacrolimus (TAC) protected podocyte via stabilizing cytoskeleton. Our latest study indicates that calcineurin binding protein 1 (Cabin1) undergoes nuclear translocation during podocytes injury. Whether TAC targets on Cabin1 during podocyte injury is still not clear. This study establishes non-immunological proteinuric model. To observe the effect of the treatment of TAC on Cabin1 expression in 5/6 nephrectomized rats. Sprague–Dawley rats were injected with TAC (0.2?mg/kg/day) for 4–8 weeks after 5/6 nephrectomy. Then, rats were sacrificed in the eighth week after operation, renal tissues were processed for morphological studies under light and electrical microscope. Cabin1 expression and distribution were detected by western blot and indirect immunofluorescence staining. In 5/6 nephrectomized rats, urinary protein excretion reached 90.2?±?30.1?mg/24?h, glomerular sclerosis index and tubulointerstitial fibrosis score were significantly increased, and widespread of podocyte foot processes fusion was found. Moreover, Cabin1 protein expression was markedly increased, and its distribution became much more obviously in podocytes nuclei. In TAC treated rats, urinary protein excretion significantly decreased (44.9?±?22.5?mg/24?h), glomerular sclerosis and tubulointerstitial fibrosis were alleviated, and podocyte foot processes fusion was inhibited. Furthermore, TAC alleviated the increased protein expression and abnormal distribution of Cabin1. In conclusion, TAC restores podocyte injury and stabilizes the expression of Cabin1. Cabin1 may become a new target to demonstrate the mechanism of TAC in podocyte injury.     

全反式维甲酸对5/6肾大部切除大鼠肾素-血管紧张素系统的影响

目的 观察全反式维甲酸（atRA）对残余肾肾素-血管紧张素系统（RAS）的影响。 方法 采用5/6肾大部切除大鼠模型，分别给予5 mg·kg-1·d-1（n＝8）、10 mg·kg-1·d-1（n＝8）、20 mg·kg-1·d-1（n＝8）的atRA灌胃。单纯肾大部切除非干预组（NX组，n＝8）和假手术组（sham组，n＝8）为对照。放射免疫法检测大鼠肾皮质肾素、血管紧张素水平。Western印迹检测肾组织血管紧张素1型受体（AT1R）水平。实时定量PCR方法检测激活蛋白1（AP-1）亚单位c-jun和c-fos mRNA的表达水平。 结果 atRA 灌胃10周时， 3种剂量atRA组收缩压明显低于NX组（P < 0.05），但不同剂量atRA组间差异无统计学意义。NX组大鼠肾皮质肾素和血管紧张素Ⅱ水平均显著高于sham组（P < 0.05）。atRA治疗组肾皮质肾素和血管紧张素Ⅱ水平均显著低于NX组，其中20 mg·kg-1·d-1组二者水平显著低于其他两个剂量组。atRA抑制残肾皮质AT1R表达约30％，而20 mg·kg-1·d-1剂量组AT1R表达水平最低。atRA组AP-1亚基c-jun和c-fos mRNA表达显著低于NX组（P < 0.05）。 结论 atRA能明显抑制5/6肾大部切除大鼠肾皮质RAS主要成分的高表达。     

三七总皂苷对5/6肾切除大鼠肾脏皮质细胞外基质积聚的影响

目的：观察三七总皂苷（PNS）对5/6肾切除大鼠肾皮质细胞外基质（ECM）积聚的影响,并探讨其肾脏保护机制。方法：将45只Wistar大鼠按体重随机取8只为正常对照组,余用5/6肾切除法建立慢性肾衰竭（CRF）动物模型。将造模成功后的大鼠随机分为模型组、百令胶囊组（简称对照组）、PNS低剂量组（低剂量组）、PNS高剂量组（高剂量组）,分别给与相应浓度和剂量的药物,实验期间测定大鼠的尿蛋白、肾功能,治疗12周后观察其肾脏病理改变,用半定量方法计算肾小球硬化指数（GSI）和肾小管损伤指数,免疫组化法检测肾小球Ⅳ型胶原（ColⅣ）、纤连蛋白（FN）和肾皮质基质金属蛋白（MMP-2）和金属蛋白酶组织抑制物（TIMP-2）蛋白表达。结果：PNS能明显减少CRF大鼠尿蛋白的排出（P〈0.05）,有一定改善肾功能的作用;PNS能减轻肾脏病理损害,减轻肾小球硬化、肾小管损伤程度;PNS能下调TIMP-2蛋白表达,增加MMP-2活性,抑制了FN、ColⅣ在肾组织的表达（P〈0.01）,减轻ECM积聚。结论：PNS可能通过减少5/6肾切除大鼠尿蛋白的排出,增加肾脏MMP-2活性,降低TIMP-2表达,增加ECM降解,减轻肾小球硬化,从而起到治疗作用。     

Lipoic acid does not improve renal function markers in 5/6 nephrectomy model: possible role of Nrf2 inactivation

Chronic kidney disease (CKD) progression and complications are associated with increased oxidative stress, as well as with Nrf2 inactivation. Lipoic acid (LA) has been considered an inducer of Nrf2 antioxidant response. We tested whether oral administration of LA provides beneficial effects in experimental CKD in rats. Wistar rats underwent 5/6 nephrectomy (CKD group) or sham laparotomy. Seven days later, CKD group was divided into three subgroups that received: (i) LA continuously in the drinking water (100?mg/kg/day), (ii) LA by gavage every other day (100?mg/kg), or (iii) no LA treatment. LA treatment lasted until day 60. Plasma urea and creatinine, 24?h-proteinuria, glomerulosclerosis, interstitial fibrosis/tubular atrophy, and Nrf2 activation were analyzed. All parameters measured were significantly altered in the untreated CKD group, compared with the sham group, as expected. Oral LA administration, either in the drinking water or by gavage, did not improve significantly any parameter, comparing the treated-groups with the untreated CKD group. These results indicate that oral LA administration for 53 days was ineffective to reactivate Nrf2 in the remnant kidney of uremic rats, likely preventing improvements in biochemical and histopathological markers of renal function.     

左归丸对5/6肾大部切除模型并肾性骨病大鼠骨代谢指标的影响

目的:探讨左归丸对5/6肾大部切除模型并肾性骨病大鼠骨代谢的影响。方法:SPF级Wistar大鼠进行5/6肾大部切除并给予高磷饮食诱导肾性骨病模型。造模大鼠分为模型组、左归丸组、骨化三醇组,并设假手术组。左归丸与骨化三醇治疗4周、12周时,检测血肌酐(Scr)、尿素氮(BUN)、血清碱性磷酸酶(ALP)、血清全段甲状旁腺激素(iPTH)、血钙(Ca2+)、血磷(P3-);药物干预12周麻醉处死大鼠,双能X线测量大鼠股骨骨密度(BMD)。结果:12周时,模型组大鼠出现了Scr、BUN、ALP、iPTH、磷升高,血Ca2+下降。左归丸能明显降低Scr、BUN水平,与模型组比较差异有统计学意义(P<0.01,P<0.05);与骨化三醇组比较差异有统计学意义(P<0.01,P<0.05)。左归丸组大鼠ALP、iPTH、血磷水平与模型组比较明显下降(P<0.05),血钙水平明显升高(P<0.01),左归丸组大鼠骨密度与模型组比较明显改善(P<0.01)。结论:左归丸通过调节钙磷代谢及参与成骨细胞代谢,对iPTH有直接的抑制作用,能改善肾性骨病的骨营养不良。     

Specific changes in plasma concentrations of matrix metalloproteinase-2 and -9, TIMP-1 and TGF-beta1 in patients with distinct types of primary glomerulonephritis.

BACKGROUND: Dysregulated renal expression of matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMP) and TGF-beta1 contribute to the development of tubulo-interstitial fibrosis characteristic of progressive forms of primary glomerulonephritis (GN). There is little information on the circulating levels of these proteins in human GNs. Here, we assessed whether different histopathological GN types could be associated with distinct plasma patterns of MMPs and regulatory proteins. METHODS: Protein levels of MMP-2, MMP-9, TGF-beta1 and TIMP-1 were measured by ELISA in plasma from venous blood of 108 untreated patients with various types of primary GN defined by kidney biopsy, namely IgAN (n=63), membranous GN (MN, n=26), minimal change nephrotic syndrome (MCNS, n=12) and focal and segmental glomerular sclerosis (FSGS, n=7), and were compared with levels in 50 healthy subjects. Plasma samples were assayed for gelatinolytic activity (zymography). RESULTS: Zymography detected the proforms of MMP-2 and MMP-9. Compared with controls, IgAN patients exhibited a significant, parallel decrease in plasma levels of MMP-2, MMP-9 and TGF-beta1. In MN patients, decreased MMP-9 level contrasted with a high MMP-2 level and a normal TGF-beta1 level. In the MCNS/FSGS group, increased MMP-2 level contrasted with unchanged MMP-9 and decreased TGF-beta1 levels. Plasma concentration of TIMP-1 was elevated in all GN groups. There was no correlation between baseline MMP-2/MMP-9/TIMP-1/TGF-beta1 levels and the degree of renal dysfunction or with progression toward ESRD. CONCLUSIONS: Plasma concentrations of MMP-2, MMP-9 and TGF-beta1 significantly differed between the various histopathological types of primary GNs, thus suggesting the involvement of different underlying mechanisms in the regulation of glomerular and tubulointerstitial fibrosis in these renal diseases.