Effect of the JAK2/STAT3 signaling pathway on epithelial mesenchymal transition of the peritoneum in uremic peritoneal dialysis rats

Objective To investigate whether the JAK2/STAT3 signaling pathway is involved in the epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells in uremic peritoneal dialysis (PD) rats. Methods A total of 48 male Sprague-Dawley (SD) rats were randomly separated into six groups: normal control group (NC group, n=8), sham group (n=8), uremic group (n=8), PD group (n=8), S3I-201 control group (n=8) and S3I-201 group (n=8). Uremic model generated by 5/6 nephrectomy surgery in rats was established. The rats of PD group, S3I-201 control group and S3I-201 group received daily infusion of 4.25% glucose-based peritoneal dialysate fluid (3 ml/100 g) from PD catheters for 28 days. Rats of S3I-201 group were injected with STAT3 inhibitor S3I-201 (2.5 mg/kg) solution from the catheters every other day; the same dose of the solvent of S3I-201 was simultaneously given to S3I-201 control group rats. After PD for 28 days, peritoneal function, pathologic changes, and microvessel density (MVD) were evaluated. Creatinine, urea nitrogen and interleukin-6 (IL-6) concentration in blood and dialysate, and protein and mRNA levels of phospho-JAK2 (p-JAK2), phospho-STAT3 (p-STAT3), E-cadherin, alpha-smooth muscle actin (α-SMA) and vascular endothelial growth factor (VEGF) in peritoneum were determined. Results Uremia and peritoneal dialysate could aggravate the peritoneal function and elevate peritoneal thickness and MVD. They could also increased the concentration of IL-6 in blood and dialysate and the expression levels of α-SMA, VEGF, p-JAK2 and p-STAT3 in peritoneum, while lowering E-cadherin expression in peritoneum. These manifestations were even more remarkable in PD group compared to those in uremic group. There was no statistical difference between the S3I-201 control group and the PD group as regards all the index (all P＞0.05). Compared with the S3I-201 control group, the rats treated with S3I-201 showed better peritoneal function. S3I-201 could reduce peritoneal thickness (P＜0.05), MVD (P＜0.05), the concentration of IL-6 in blood and dialysate, the mRNA and protein expression of α-SMA, VEGF, p-JAK2 and p-STAT3 (all P＜0.05), while enhance the mRNA and protein expression of E-cadherin (all P＜0.05). Conclusions After STAT3 is inhibited, the peritoneal thickness, MVD and IL-6 concentration in PD rats are decreased, and EMT is also inhibited, while peritoneal function is improved. The JAK2/STAT3 signaling pathway may thus be involved in the process of EMT of peritoneum in uremic peritoneal dialysis rats by regulating the expression of IL-6.     

肾疏宁抑制腹膜透析腹膜纤维化大鼠基质及新生血管的实验研究

目的:观察中药肾疏宁对腹膜纤维化大鼠腹膜功能、腹膜组织基质积聚、新生血管、结缔组织生长因子(CT-GF)、血管内皮生长因子(VEGF)、肝细胞生长因子(HGF)及骨形态蛋白-7(BMP-7)表达的影响。方法:腹膜透析液+阿霉素注射法诱发SD大鼠腹膜透析腹膜纤维化模型,依体重随机分为4组,1.5%腹膜透析液模型组、4.25%腹膜透析液模型组、1.5%腹膜透析液+肾疏宁干预组及4.25%腹膜透析液+肾疏宁干预组,每组各15只,另设空白对照组(对照组,15只)。1.5%腹膜透析液+肾疏宁干预组及4.25%腹膜透析液+肾疏宁干预组予肾疏宁(按43.93g.kg-1.d-1)灌胃,对照组和模型组予等量生理盐水灌胃。检测腹透液葡萄糖浓度,计算超滤量(UF)及葡萄糖转运量(MGT)。观察腹膜病理形态学改变,分析腹膜厚度、腹膜血管计数、腹膜纤维连接蛋白(FN)及CTGF、VEGF、HGF、BMP-7表达。结果:治疗第6周末,1.5%腹膜透析液+肾疏宁干预组及4.25%腹膜透析液+肾疏宁干预组腹膜透析腹膜纤维化大鼠超滤量(-3.26±14.17)ml及(-2.04±10.74)ml、葡萄糖转运量(18.12±0.81)mmol/kg及(16.14±1.20)mmol/kg、腹膜厚度(74.68±15.33)μm及(211.75±58.23)μm、腹膜血管计数(8.21±2.66)个/mm2及(13.70±4.71)个/mm2、FN(152.47±36.94)%及(231.49±53.49)%、CTGF(708.67±127.22)%及(791.20±126.37)%、VEGF(0.42±0.08)%及(0.50±0.09)%、HGF(245.71±24.38)%及(222.05±23.43)%、BMP-7(351.27±31.99)%及(284.43±26.82)%,与同浓度透析液组比较,差异有统计学意义(P<0.05,P<0.01)。结论:肾疏宁可能通过调控CTGF、VEGF、HGF、BMP-7表达,阻抑基质过度积聚及新生血管生成,进而延缓腹膜透析大鼠腹膜纤维化进展。     

Expression of miR-200a in peritoneal fibrosis associated with peritoneal dialysis

Objective To find the key miRNA that relative to peritoneal fibrosis associated with peritoneal dialysis (PD) by microarray technology, and verify its expression in vitro and in vivo. Methods The peritoneal fibrosis mouse model associated with PD were established by intraperitoneal injection of lipopolysaccharide (LPS) + 4.25% peritoneal dialysate. The expression of miRNA was detected by microarray in peritoneal tissues. The expression of miRNA profiles between fibrotic and normal peritoneal tissues was compared. The differentially expressed miRNA (miR-200a) was validated by real-time PCR in lager sample size cohorts. The expressions of miR-200a were also detected in the epithelial-mesenchymal transition (EMT) process of human peritoneal mesothelium cells. Results In mice model of PD, peritoneal tissue was markedly thickened and with a massive extracellular matrix accumulation. In contrast with control, the expression level of epithelial marker E - cadherin was significantly decreased, α - SMA, Col - I and FN were remarkably increased (P ﹤ 0.05). By miRNA microarray analysis, miR - 200a was significantly down - regulated (3.31 folds change, P ﹤ 0.05) in fibrotic peritoneal tissues. The down-regulated expression level of miR-200a was also validated by real- time PCR in larger cohorts (P ﹤ 0.05). Then, the expression level of miR-200a was detected in the EMT process of human peritoneal mesothelium cells. During the process of TGF-β1 induced EMT, miR -200a was significantly down-regulated compared with the control (P﹤0.05). Conclusions Down- regulated expression of miR-200a was observed both during peritoneal fibrosis and TGF-β1 induced EMT in vivo and in vitro, suggesting that miR - 200a may be involved in the peritoneum fibrosis by regulating the target genes of EMT.     

Effect and mechanism of fluvastatin on the expression of fibronectin in human peritoneal mesothelial cells induced by high?glucose peritoneal dialysate

Objective To explore the effect and mechanism of fluvastatin on the expression of fibronectin(FN) in human peritoneal mesothelial cells (HPMCs) induced by high?glucose peritoneal dialysate (HGPDS). Methods Cultured HPMCs were randomly divided into control, HGPDS, HGPDS plus GSK650394 10-5 mol/L (the competitive inhibitor of SGK1), different concentrations of fluvastatin, fluvastatin 10-6 mol/L and GSK650394 10-5 mol/L alone. The morphology change of HPMC was observed by light microscopy. The cellular viability was detected by MTT colorimetry. The mRNA and protein expressions of serum and glucocorticoid?inducible kinase 1 (SGK1) and FN were detected by RT?PCR, Western blotting or ELISA. Results After incubation with HGPDS, the cell morphology changed from typical cobblestone?like appearance to fibroblast?like appearance, and the cell viability was inhibited significantly (P<0.05). Fluvastatin 10?6mol/L and GSK650394 could improved the cell morphology and the cell viability injured by HGPDS (P<0.05). Compared with the normal control group, the mRNA and protein expressions of SGK1 and FN increased significantly in HPMC treated with HGPDS(P<0.05). GSK650394 significantly decreased the high expression of SGK1 and FN (P<0.05), also the fluvastatin had same effects as GSK650394 in dose?dependent manner (P<0.05). Conclusions High?glucose peritoneal dialysate can increase FN expression in human peritoneal mesothelial cells, which can be attenuated by fluvastatin. The protective role of fluvastatin in HPMC may be partially achieved through the signal pathway of SGK1.     

Effects of atorvastatin on development of peritoneal fibrosis in rats on peritoneal dialysis

Rational: Peritoneal sclerosis is one of the important complications of long-term peritoneal dialysis (PD). In this study, efficacy of atorvastatin on peritoneal histology and functions in non-uremic rats on PD was tested. Objectives: Twenty-two non-uremic Wistar albino rats were randomized into three groups: Sham (intraperitoneal saline), peritoneal dialysis (PD, intraperitoneal 3.86% dextrose containing PD solution), and treatment (TX, intraperitoneal 3.86% dextrose containing PD solution plus atorvastatin added into drinking water). At the end of a 4-week period, 1 h peritoneal equilibration test was performed. Serum lipids and certain cytokines, mediators, markers, and antioxidant enzyme activities in serum and dialysate were studied. Peritoneal thickness was measured and peritoneal inflammation, fibrosis, and vascular proliferation were scored in histological sections. Main findings: In histological examinations, inflammation, fibrosis, and vascular proliferation were significantly more frequent in PD group than Sham group and it seemed to decrease significantly when atorvastatin was used in conjunction with PD. Additionally, peritoneum was significantly thicker in PD group when compared to that of Sham and TX groups. Serum parameters did not significantly differ between groups. On the other hand, dialysate glutathione reductase (GR) activity and TGF-β were significantly lower in TX group than that of the PD group, whereas dialysate IL-6 level was higher in TX group. Principal conclusions: In our study, atorvastatin use appeared to diminish structural changes in peritoneum. Decreased expression of TGF-β in dialysate may be one of the possible underlying mechanisms.     

扶肾颗粒对腹膜透析相关性腹膜纤维化的影响及其作用机制的实验研究

目的:通过对腹膜透析大鼠进行干预,观察扶肾颗粒对腹膜纤维化相关细胞因子的影响及其作用机制探讨。方法:SPF级健康雄性SD大鼠75只,体重180～200g,适应性饲养1周后,依大鼠体重分层,随机分为:正常对照组(A组,n=15),无任何处理,腹腔注射生理盐水,100ml.kg-1.d-1,连续4周;肾衰5/6切除+1.5%PD组(B组,n=15);肾衰5/6切除+1.5%PD+扶肾颗粒组(C组,n=15);肾衰5/6切除+4.25%PD组(D组,n=15);肾衰5/6切除+4.25%PD+扶肾颗粒组(E组,n=15),除A组外,各组均制成肾衰模型,其中B、C组予腹腔注射1.5%LPDS,100ml.kg-1.d-1,连续4周;D、E组予腹腔注射4.25%LPDS,100ml.kg-1.d-1,连续4周,自透析开始,对C组和E组予灌服扶肾颗粒,以200gSD大鼠计算,灌胃剂量1.8ml/d。其余各组予灌服2ml生理盐水,共灌服4周。观察各组实验动物的大体状态、体重变化、腹膜滤过功能及血清纤维化调控因子表达变化。结果:在治疗4周后,除正常对照组(A组)外,其余各组均体现为负超滤,但是,同浓度透析治疗组中,应用扶肾颗粒干预组其超滤情况明显优于未应用扶肾颗粒组(P<0.05),其作用显著,同时,葡萄糖转运量方面亦体现为相似结果。与正常对照组比较(A组),其余各模型组相关促纤维化因子表达水平均明显升高(P<0.01)。TGF-β1方面,D组的表达水平明显较其他各组升高(P<0.05)。CTGF及IL-6方面,结果与TGF-β1相似。VEGF方面,E组较D组明显降低(P<0.05)。随着透析治疗的进行,HGF与BMP-7表达水平均反应性升高,各模型组二者水平均较正常对照组明显升高(P<0.01)。HGF方面,C组较B组明显升高(P<0.01)。BMP-7方面,E组较D组明显升高(P<0.05)。结论:扶肾颗粒可减轻腹透大鼠的肾功能损伤,保护残余肾功能,改善腹透大鼠的超滤量及葡萄糖转运量,抑制促纤维化因子TGF-β1、CTGF、IL-6、CTGF等表达,调高抗纤维化因子HGF、BMP-7的表达,进而起到抑制腹膜透析相关腹膜纤维化的发生,改善腹膜透析效能。     

Effects of 1,25-dihydroxyvitamin D3 on the expression of connective tissue growth factor and heat shock protein 47 in peritoneum fibrosis rats

Objective To investigate the expression of connective tissue growth factor (CTGF) and heat shock protein 47 (HSP47) in peritoneum fibrosis rats, and the mechanism of 1,25-dihydroxyvitamin D3 [1,25-(OH)2-VitD3] in inhibiting the peritoneum fibrosis. Methods Adult male Sprague-Dawley rats were randomly divided into 3 groups: control group (n=8), model group (n=8) and 1,25-dihydroxyvitamin D3 group (VitD3, n=8). The model of peritoneum fibrosis rats were induced by daily intraperitoneally injection of 15% chlorhexidine gluconate (CHX) 0.2 ml/d with 0.1% glucose for 4 weeks. Rats in VitD3 group were also treated with 1,25-(OH)2-VitD3 [i.p. 6 ng?(100 g)-1?d-1]. Peritoneal transport function, renal function, peritoneum thickness and serum level of 25 hydroxyvitamin D3 were detected. In vitro, primary cultured peritoneal mesothelial cells were divided into control group, high glucose group (HG, 2.5%), CTGF siRNA intervention group (CTGF siRNA+HG), VitD3 intervention group (VitD3+HG) and combined intervention group (CTGF siRNA+VitD3+HG). Real-time PCR, Western blotting and immunofluorescence were applied to measure the expression of CTGF and HSP47, also ELISA was used to detect the protein level of FN in peritoneum and peritoneal mesothelial cells. Results Compared with control group, the peritoneal ultrafiltration in peritoneum fibrosis rats were significantly decreased (P＜0.05), the absorbance level of peritoneal fibrosis, peritoneum thickness, the rate of dialysate urea nitrogen and blood urea nitrogen (DUN/BUN) and the expressions of CTGF and HSP47 were increased (all P＜0.05). After application of 1,25-dihydroxyvitamin D3, peritoneal fibrosis lesion was significantly improved, the peritoneum thickness, the expressions of CTGF and HSP47 were decreased (all P＜0.05). In vitro, 2.5% high glucose induced-peritoneal mesothelial cells were respectively treated by CTGF siRNA, 1,25-(OH)2-VitD3 and combined interventions, the expression of FN, CTGF and HSP47 was significantly lower than that in high glucose group (all P＜ 0.05). Conclusions The expression of CTGF and HSP47 is significantly increased in peritoneal fibrosis rats. 1,25-(OH)2-VitD3 may ameliorate the progression of peritoneal fibrosis via reducing the expression of CTGF, decreasing the expression of HSP47 and FN.     

Effect of suramin on the epithelial-mesenchymal transition in peritoneal mesothelial cells induced by high concentration glucose

Objective To explore the effect of suramin on the epithelial-mesenchymal transition (EMT) and the excretion of transforming growth factor-β1 (TGF-β1) in peritoneal mesothelial cells (PMCs) induced by high concentrations of glucose solution (GS). Methods Cultured PMCs were divided into three groups: (1) normal control group; (2) GS-treated group: cells were treated with 1.5%, 2.5%, 4.25% GS for 12 h, 24 h, 48 h, respectively; (3) Suramin-treated group: PMCs cultured with 4.25% GS were exposed to different doses of suramin (25, 50, 100 μmol/L) for 48 h. Expression levels of α-smooth muscle actin (α-SMA) and E-cadherin were detected by Western blotting and the concentration of TGF-β1 in the culture supernatant was determined by ELISA. Results Compared with normal control group, GS-treated PMCs exhibited a time-dependent increase in the expression of α-SMA, and decrease in the expression of E-cadherin. GS also stimulated PMCs to secrete TGF-β1. In the presence of suramin, GS-induced α-SMA expression and TGF-β1 production were reduced, E-cadherin expression was increased. Conclusions Suramin can inhibit high glucose-induced EMT of PMCs by down-regulating the expression of TGF-β1. Suramin may be a novel therapeutic agent for the treatment of peritoneal fibrosis.     

内皮抑素在大鼠腹膜的表达及其与腹膜血管新生的关系

目的 研究大鼠腹膜血管内皮抑素（endostatin, ES）基因及蛋白表达与腹膜血管新生的关系。 方法 32只雄性SD大鼠,按随机数字表法分为正常组、肾衰竭非透析组（非腹透组）、1.5%腹膜透析组（1.5% PD组）、4.25%腹膜透析组（4.25% PD组）,每组8只。PD组经规律PD 28 d后,取各组大鼠新鲜腹膜组织,用RT-PCR检测ES mRNA表达;用组织免疫组化染色检测ES蛋白表达;以CD34染色观察腹膜组织毛细血管密度（MVD）。 结果 各组均有ES mRNA表达,正常组为0.47±0.05;非腹透组为0.45±0.04;1.5% PD组为0.46±0.04;4.25% PD组为0.47±0.03;各组表达差异无统计学意义。正常组ES蛋白表达积分0分;非腹透组积分2分;1.5%PD组积分4分;4.25%PD组呈高表达,积分9分。正常组MVD为3.13±1.13;非腹透组为5.13±1.14;1.5%PD组为9.00±1.51;4.25%PD组为10.75±1.83;组间差异均有统计学意义（P < 0.05）。 结论 尿毒症状态和非生理性腹透液刺激可使大鼠腹膜组织ES蛋白表达升高,其在长期透析所致腹膜组织毛细血管生成增多中可能发挥一定的作用。     

重组人内皮抑素对尿毒症腹膜透析大鼠腹膜新生血管形成的影响

目的 研究重组人内皮抑素对尿毒症腹膜透析（PD）大鼠腹膜新生血管形成的影响。 方法 40只雄性SD大鼠,按随机数字表法分为正常对照组、肾衰竭非透析组、4.25%PD组、重组人内皮抑素10 mg/kg PD组、重组人内皮抑素40 mg/kg PD组,每组8只。对PD组规律PD 28 d。重组人内皮抑素干预组在行规律PD期间,隔天1次皮下注射重组人内皮抑素,至透析第28天结束。28 d后取各组大鼠新鲜腹膜组织,RT-PCR法检测腹膜组织血管内皮生长因子（VEGF）、碱性成纤维细胞生长因子（bFGF） mRNA表达;免疫组化染色检测VEGF、bFGF蛋白表达。CD34染色观察腹膜组织毛细血管密度（MVD）。 结果 各组大鼠腹膜组织均表达VEGF和bFGF,肾衰竭非透析组、4.25%PD组VEGF及bFGF mRNA、蛋白表达均显著高于正常对照组（均P < 0.05）;重组人内皮抑素10 mg/kg PD组、40 mg/kg PD组VEGF及bFGF mRNA、蛋白表达均显著低于4.25%PD组（均P < 0.05）。肾衰竭非透析组、4.25%PD组腹膜组织MVD均显著高于正常对照组（均P < 0.05）;重组人内皮抑素10 mg/kg、40 mg/kg PD组腹膜组织MVD均显著低于正常对照组（均P < 0.05）。 结论 重组人内皮抑素可以有效抑制PD大鼠腹膜新生血管的形成,下调VEGF、bFGF mRNA及蛋白表达可能是其抑制腹膜新生血管形成的机制之一。     

Octreotide lessens peritoneal injury in experimental encapsulated peritoneal sclerosis model

Aim: Encapsulated peritoneal sclerosis is characterized by neoangiogenesis and fibrosis. Octreotide, a somatostatin analogue is a well‐known antifibrotic, antiproliferative and anti‐angiogenic agent. The aim of the study is to evaluate the effects of octreotide in encapsulated peritoneal sclerosis‐induced neoangiogenesis and fibrosis and compare the results with resting. Methods: Non‐uraemic Wistar‐Albino male rats (n = 35) were divided into four groups. Group I, control rats, received 2 mL isotonic saline i.p. daily for 3 weeks. Group II, received daily i.p. 2 mL/200 g injection of chlorhexidine gluconate (0.1%) and ethanol (%15) dissolved in saline for 3 weeks. Group III, chlorhexidine gluconate for 3 weeks plus an additional 3 weeks without any treatment (rest), to a total of 6 weeks. Group IV, chlorhexidine gluconate for 3 weeks plus an additional 3 weeks octreotide, 50 mcg/kg bodyweight s.c., for a total of 6 weeks. Results: Octreotide significantly reversed ultrafiltration capacity of peritoneum with decreasing inflammation, neoangiogenesis and fibrosis compared to the resting group. Octreotide also caused inhibition of dialysate transforming growth factor‐β1, vascular endothelial growth factor and monocyte chemotactic protein‐1 activity and improved mesothelial cell cytokeratin expression. Peritoneal resting has no beneficial effects on peritoneum. Conclusion: In conclusion, octreotide may have a therapeutic value in peritoneal dialysis patients who suffer from encapsulated peritoneal sclerosis.     

PI3K/Akt signaling regulates epithelial-mesenchymal transition of peritoneal mesothelial cells in peritoneal dialysis

Objective To investigate the role of PI3K/Akt signaling in the regulation of epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) in peritoneal dialysis in vitro and in vivo. Methods The level of Phosphorylated serine/threonine kinase Akt and the expression of EMT associated gene and protein, including ZO-1, Vimentin and FN, were measured in mice EMT model. In vitro study, phosphorylation level and nuclear translocation of Akt, ZO - 1 and Vimentin expression induced by TGF - β1 in human peritoneal mesothelial cells (HPMCs) were also observed. Moreover, HPMCs were pre-treated by one of PI3K/Akt inhibitor, LY294002, or transfected with dominant-negative Akt plasmid to inhibit PI3K/Akt signaling, then analyzed its effect on Zo-1 and Vimentin expression induced by TGF-β1. Results Compared with the control, thickened parietal peritoneum and remarkable decrease in mRNA and protein of the epithelial marker ZO-1, and notable increased in the expression of mesenchymal markers Vimentin and FN were observed in PD mice (all P＜0.01). Moreover, the phosphorylation of Akt also significantly increased under above condition (P＜ 0.01). In vitro study, with the stimulation of TGF-β1, the expression of Zo-1 was down-regulated, while the expression of Vimentin increased (all P＜0.01). In addition, TGF-β1 remarkably increased pAkt in HPMCs (all P＜0.01) in dose-dependent. However, LY294002 and DN-Akt dramatically inhibited the vimentin expression in HPMCs induced by TGF-β1 after inhibition of pAkt. On the other hand, the expression of ZO - 1 also was restored (P＜0.01). Conclusion PI3K/Akt signaling is involved in EMT of peritoneal mesothelial cells in peritoneal dialysis, and may be a new target for the prevention and treatment of peritoneal fibrosis during PD.     

上调Smad7表达对腹膜纤维化大鼠腹膜炎症细胞浸润及促炎症因子表达的影响

目的 研究基因转染上调Smad7表达对大鼠腹膜纤维化模型腹膜炎症细胞浸润及促炎症因子表达的影响。方法 48只SD大鼠随机分为（1）正常对照组（n=12）；（2）模型组（n=12）：每日给予腹腔注射4．25％葡萄糖腹膜透析液（100ml／kg），同时于第8、10、12、22、24、26天腹腔注射脂多糖（LPS，0．6mg／kg）；（3）空白载体对照组（n=12）：仅转入不含Smad7的Tet-on／vector空白载体；（4）Smad7基因转染组（n=12）：在造模后第0、14天分别转染Smad7。第28天时杀检，分别应用免疫荧光染色及RT-PCR检测脏层腹膜泛白细胞标志性抗原（OX-1）、单核巨噬细胞抗原（ED-1）、白介素1（IL-1）、肿瘤坏死因子α（TNF-α）蛋白和mRNA的表达水平。Smad7基因转染采用超声介导的微泡基因转染技术。结果 与模型组及空白载体转染组比较．Smad7转基因组脏层腹膜OX-1、ED-1阳性细胞以及IL-1、TNF-α表达水平有明显的减少，但均高于正常对照组。结论 高糖腹膜透析液联合LPS可刺激腹膜炎症细胞的浸润及腹膜间皮细胞IL-1、TNF-α表达上调。基因转染上调Smad7表达可明显抑制大鼠腹膜纤维化模型腹膜炎症细胞浸润及促炎症因子的表达上调。     

一氧化氮及其抑制剂对大鼠腹膜通透性的作用

目的 研究一氧化氮(NO)及一氧化氮抑制剂(L-NMMA)对腹膜透析通透性,特别是高糖透析中的作用。方法 建立大鼠长期腹膜透析模型,测定不同浓度透析液中以及不同刺激条件下腹膜巨噬细胞产生NO的水平。分别用1.5％、4.25％的葡萄糖透析液及分别加L-NMMA(5mg·kg~(-1)·d~(-1))行SD大鼠透析。10d后测定其腹膜动力学的变化。结果 腹膜巨噬细胞产生NO的水平,4.25％的葡萄糖透析液高于1.5％葡萄糖透析液(P<0.01),而后者又高于生理盐水(P<0.01)。高糖透析可减少腹膜的液体超滤(P<0.05)及溶质的转运。加用L-NMMA后腹膜的液体超滤及溶质的转运增加(P<0.05)。结论 腹膜透析时腹腔产生NO的水平增高,对腹膜的通透性增高中起一定作用。透析液中加入L-NMMA可改善腹膜的通透性。     

Dialysate as food: combined amino acid and glucose dialysate improves protein anabolism in renal failure patients on automated peritoneal dialysis

Protein-energy malnutrition as a result of anorexia frequently occurs in dialysis patients. In patients who are on peritoneal dialysis (PD), dialysate that contains amino acids (AA) improves protein anabolism when combined with a sufficient oral intake of calories. It was investigated whether protein anabolism can be obtained with a mixture of AA plus glucose (G) as a source of proteins and calories during nocturnal automated PD (APD). A random-order cross-over study was performed in eight APD patients to compare in two periods of 7 d each AA plus G dialysate obtained by cycler-assisted mixing of one bag of 2.5 L of AA (Nutrineal 1.1%, 27 g of AA) and four bags of 2.5 L of G (Physioneal 1.36 to 3.86%) versus G as control dialysate. Whole-body protein turnover was determined using a primed continuous infusion of L-[1-13C]leucine, and 24-h nitrogen balance studies were performed. During AA plus G dialysis, when compared with control, rates of protein synthesis were 1.20 +/- 0.4 and 1.10 +/- 0.2 micromol/kg per min leucine (mean +/- SD), respectively (NS), and protein breakdown rates were 1.60 +/- 0.5 and 1.72 +/- 0.3 micromol/kg per min (NS). Net protein balance (protein synthesis minus protein breakdown) increased on AA plus G in all patients (mean 0.21 +/- 0.12 micromol leucine/kg per min; P < 0.001). The 24-h nitrogen balance changed by 0.96 +/- 1.21 g/d, from -0.60 +/- 2.38 to 0.35 +/- 3.25 g/d (P = 0.061, NS), improving in six patients. In conclusion, APD with AA plus G dialysate improves protein kinetics. This dialysis procedure may improve the nutritional status in malnourished PD patients.     

Effects of cyclooxygenase - 2 inhibitor on peritoneal function and angiogenesis in uremic peritoneal dialysis rats

Objective To investigate the effects of the cyclooxygenase-2 (COX-2) inhibitor (celecoxib) on angiogenesis and peritoneal function of uremic peritoneal dialysis rats. Methods Forty - eight male SD rats were selected, and they were randomly divided into five groups: normal control group(n=8), sham operation group(n=8), uremia group(5/6 nephrectomy, n=8), PD group [4.25% PD solution, 2 weeks PD model(n=8) and 4 weeks PD model(n=8)], PD + celecoxib intervention group[treated by celecoxib(20 mg/kg) via oral gavage, n=8].The peritoneum of uremic peritoneal dialysis rats was observed in different dialysis time from peritoneal structures, functions, peritoneal tissue capillary density (microvessel density, MVD) and COX-2, vascular endothelial growth factor (VEGF) expression level, and the impacts of celecoxib on uremic peritoneal dialysis rats peritoneal angiogenesis and peritoneal function were study. Results With the conduct of the peritoneal dialysis, peritoneal thickness increased, the inflammatory cells infiltrated, peritoneal equilibration test (PET) showed that ultrafiltration volume decreased significantly (P＜0.05), the amount of glucose transport rate rised significantly (P＜0.05), but the celecoxib could improve net ultrafiltration volume (P＜0.05), and reduce the glucose transport rate (P＜0.05). The peritoneal tissue MVD and COX - 2, VEGF expression were significantly increased in uremia group and PD group compared with that in the normal control group (all P＜0.05), were significantly lower in PD + Celecoxib intervention group than that in uremia group (P＜0.05). The correlation analysis showed that the level of COX-2 protein expression with MVD, VEGF protein expression was positively correlated (both P＜0.05), the level of VEGF protein expression and MVD was positively correlated (P＜0.05). Conclusions In vivo high glucose dialysate and uremia environmental can stimulate the COX-2 and VEGF expression raised, and the capillaries production increased in peritoneal tissue. Celecoxib can alleviate the change of peritoneal tissue morphology and function in long-term peritoneal dialysis rats. Celecoxib inhibits the peritoneal neovascularization of uremic peritoneal dialysis rats, possibly through inhibition of COX-2 expression to reduce the production of VEGF.     

The effect of colchicine on the peritoneal membrane

Peritoneal dialysis (PD) is a treatment modality for patients with renal failure. Peritoneal fibrosis is one of the most serious complications after long-term continuous ambulatory peritoneal dialysis (CAPD). Histological studies in both humans and animals show that chronic peritoneal dialysis results in fibrosis of the peritoneal membrane. In our study, we investigated the effect of colchicine on peritoneal alterations induced by hypertonic PD solution in rats. Sprague-Dawley rats intraperitoneally received saline (control group) once daily, for 28 days, or 3.86% glucose (PDF group), or 3.86% glucose plus colchicine (colchicine group). Animals from each group were sacrificed after 28 days with anesthetized ketamine (60 mg/kg BW). For the PD fluid assessment, 1 h before the sacrifice of animals, 10 mL PD fluid of 2.27% glucose was given, and this fluid was obtained after the sacrifice. The levels of transforming endothelial growth factor beta (TGF-beta), tumor necrosis factor alpha (TNF-alpha) and albumin were investigated both in the peritoneal dialysate and blood, and the levels of malondialdehyde (MDA) were investigated only in peritoneal dialysate. The peritoneal membrane was evaluated histologically by light microscopy. When groups were compared in terms of body weight change, the colchicine group significantly lost weight compared to controls and PDF group (-4.7% + 4.5, 3.5% +/- 7.2, 3.0% +/- 1.3, respectively, p = 0.018). Also, the blood albumin level was significantly lower for these in the colchicine group compared to those in the PDF group (2.7 +/- 0.35 versus 3.2 +/- 0.3 g/dL, respectively, p = 0.048). The blood TGF-beta level was significantly lower in the control group, and no difference was observed between the PDF and colchicine groups (294.4 +/- 67.5 versus 787.4 +/- 237.4 versus 615.3 +/- 235.1 pg/mL, respectively, p = 0.004). The mesothelial thickness found in groups was as follows: control group 102 +/- 18.9 microm, PDF group 128.33 +/- 33.1 microm, colchicine group 117 +/- 35.6 microm (p = 0.34). In conclusion, a rat model for peritoneal dialysis associated peritoneal derangement without fibrosis could be induced. Colchicine could not prevent peritoneal derangement in this model.     

Effects of glucose dialysate on extracellular matrix production by human peritoneal mesothelial cells (HPMC): the role of TGF-beta.

BACKGROUND: Dialysate glucose has been implicated in the loss of peritoneal membrane function seen in long-term CAPD patients. METHODS: In order to investigate this in vitro, human peritoneal mesothelial cells (HPMC) were cultured in a 50:50 mix of dialysis solution and M199 for 12 h. The dialysate was laboratory manufactured and designed to be identical in composition to PD4 (LAB). The final glucose concentration ranged between 5 and 40 mmol/l. Experiments were conducted in the presence and absence of an anti-transforming growth factor-beta (TGF-beta) antibody. Cell viability was measured by lactate dehydrogenase (LDH) release. Fibronectin (FN) and TGF-beta protein were measured by ELISA, and FN gene expression was measured by Northern analysis. Separately, the effects of recombinant TGF-beta(1) added to M199: dialysate at 5 mmol/l glucose were investigated. RESULTS: Forty millimoles per litre d-glucose LAB caused a decrease in cell viability, as evidenced by an increase in LDH release (6.0+/-1.3 vs 2.6+/-0.7%). This effect was dependent on osmolality. Forty millimoles per litre d-glucose LAB stimulated a 15.4+/-4.6% increase in FN, a 46.5+/-18.3% increase in TGF-beta protein (both P<0.05), and 1.4+/-0.09-fold increase in FN mRNA compared with 5 mmol/l d-glucose LAB. Exogenous TGF-beta 0-1 ng/ml induced a dose-dependent increase in FN protein (280+/-45% increase at TGF-beta 1 ng/ml, P<0.0001), and FN mRNA levels (10.0+/-1.8-fold at TGF-beta 1 ng/ml). The increase in FN in response to 40 mmol/l glucose was significantly reduced by anti-TGF-beta antibody to levels not different from control (93.8+/-6.6%, P<0.05 vs no Ab). CONCLUSIONS: These data suggest that the pro-fibrotic effect of glucose dialysate on HPMC is mediated through stimulation of TGF-beta, which promotes FN gene expression and protein production.