商陆皂苷甲对大鼠抗Thy1系膜增生性肾炎的治疗作用

目的：探讨商陆皂苷甲（EsA）对大鼠抗Thy1系膜增生性肾炎的治疗作用。方法：制备大鼠抗Thy1系膜增生性肾炎模型,随机分为EsA治疗组、地塞米松治疗组、未治疗组（模型组）。另设正常对照组。隔日测定24h尿蛋白定量。所有大鼠第8天处死,取肾脏组织,显微镜观察肾组织系膜增生程度,利用图像分析系统对系膜区占据肾小球面积进行分析。结果：EsA治疗组及地塞米松治疗组3、5、7天24h尿蛋白与模型组相应时间点比较均明显下降（P〈0.01～0.001）;EsA治疗组及地塞米松治疗组肾小球系膜细胞及基质增生程度较模型组明显减轻（P〈0.05）。结论：EsA对大鼠抗Thy1系膜增生性肾炎具有降低尿蛋白、抑制肾小球系膜细胞及系膜基质的增生的作用。     

藕节对糖尿病肾病大鼠肾组织JAK2/STAT3及凋亡因子表达的影响

也页目的：探讨藕节对糖尿病肾病大鼠肾组织p-JAK2、p-STAT3及凋亡因子Bcl-2、Bax表达的影响。方法：健康雄性SD大鼠60只,随机选取10只为正常组（ N组）,其余采用单次腹腔注射链尿佐菌素（ STZ,45 mg/kg）制作DN模型,造模成功后随机分为糖尿病肾病组（DN）、藕节小剂量组（RL,1.5 g·kg-1·d-1）、中剂量组（RM,3.0 g·kg-1·d-1）、大剂量组（RH,6.0 g·kg-1·d-1）及氯沙坦钾组（LP,30 mg·kg-1·d-1）,均采用灌胃给药,N组和DN组给予等量蒸馏水。12周后检测大鼠生化指标;HE、Masson染色及电镜观察肾脏病理改变;免疫组化法测定p-JAK2、p-STAT3、Bcl-2及Bax在肾组织表达情况;原位末端标记法（ TUNEL）检测肾组织细胞凋亡情况。结果：实验12周末,与N组比较,DN组大鼠肾小球肥大、系膜基质增多、细胞凋亡明显,BUN、Scr、24 h尿蛋白定量明显升高（P〈0.05）,肾组织Bax、p-JAK2、p-STAT3表达明显上调,Bcl-2表达下调（P〈0.05）;与DN组比较,藕节中、高剂量组肾脏病理改变减轻、细胞凋亡减少,24 h尿蛋白定量较DN组明显降低（P〈0.05）,但降尿蛋白作用弱于氯沙坦钾组,同时肾组织Bax、p-JAK2、p-STAT3表达下调,Bcl-2表达上调（P〈0.05）。结论：藕节可能通过上调Bcl-2在肾组织的表达,下调Bax、p-JAK2、p-STAT3的表达,从而减少尿蛋白,延缓DN进展。     

大剂量甲基强的松龙对大鼠急性脊髓损伤后神经细胞Bcl-2表达及细胞凋亡的影响

目的：观察大剂量甲基强的松龙（MP）治疗对大鼠急性脊髓损伤（ASCI）后神经细胞凋亡及凋亡基因Bcl-2的影响。方法：选取48只雌性SD大鼠随机等分为2组,对照组与治疗组,按Nystrom法制备大鼠急性脊髓损伤模型。治疗组伤后30min经腹膜腔注入MP30mg／kg,以后每小时腹膜腔注入MP5．4mg／kg,维持24h;对照组应用生理盐水替代MP,处理方法同治疗组。两组分别于伤后4、8h及1、3、7、14d灌注固定后取材。免疫组织化学检测损伤段脊髓内Bcl-2蛋白表达,TUNEL检测细胞凋亡,染色结果应用图像分析仪进行半定量分析。结果：大鼠ASCI后4h即可见脊髓内TUNEL阳性细胞,8h表达达高峰,此后表达量逐渐下降,14d时仍可见少量阳性细胞。凋亡相关蛋白Bcl-2在伤后4h即可见表达,伤后1d达高峰,伤后14d仍有表达,与对照组相比,治疗组伤后8h、1d和3d时凋亡细胞数减少有统计学意义,伤后8h和1d Bcl-2蛋白表达增高有统计学意义。结论：大剂量甲基强的松龙治疗可抑制大鼠ASCI后神经细胞凋亡,并增加凋亡相关蛋白Bcl-2的表达：     

L-精氨酸对局灶性脑缺血损伤大鼠脑组织TNF-α、IL-1β及神经元凋亡的影响

目的探讨L-精氨酸对局灶性脑缺血损伤大鼠脑组织肿瘤坏死因子-α（TNF-α）、白细胞介素-1β（IL-1β）及神经元凋亡的影响。方法健康雄性SD大鼠30只,体重250～280g,随机分为3组（n=10）：假手术组（SH组）、缺血组（IS组）和L-广精氨酸治疗组（L-arg组）。L-arg组腹腔注射L-精氨酸500mg/kg,每日2次,连续3d;IS组给予等容量的生理盐水;2组均采用线栓法制备大鼠局灶性脑缺血损伤模型。将大鼠断头取脑,采用免疫组化法检测脑组织TNF-α表达,放免法检测脑组织IL-1β含量,流式细胞仪测定神经元凋亡情况、Bcl-2蛋白、Bax蛋白表达计算Bcl-2/Bax蛋白比值。结果与SH组比较,IS组脑组织TNF-α表达、IL-1β含量、神经元凋亡率升高,Bax蛋白表达上调,Bcl-2/Bax蛋白比值降低（P〈0.01）;与IS组比较,L-arg组脑组织TNF-α表达、IL-1β含量、神经元凋亡率降低,Bcl-2蛋白表达上调,Bax蛋白表达下调,Bcl-2/Bax蛋白比值升高（P〈0.01）。结论L-精氨酸通过抑制脑组织TNF-α和IL-1β水平的升高,上调Bcl-2蛋白表达,下调Bax蛋白表达,调节Bcl-2/Bax蛋白比值平衡,抑制神经元凋亡,从而对脑缺血大鼠神经元产生一定程度的保护作用。     

骨碎补类黄酮对系膜增殖性肾小球肾炎大鼠模型的抑制作用

目的:探讨骨碎补类黄酮提取物(flavonoid fraction,FF)对单克隆抗体OX-7诱导的系膜增殖性肾小球肾炎大鼠模型(anti-Thy 1.1 GN)的作用.方法:利用单克隆抗体OX-7诱导的anti-Thy 1.1 GN动物模型,将大鼠随机分成正常对照组、模型组(Thy 1.1 GN)、Thy 1.1 GN FF组、FF组.检测尿蛋白,三色染色评估肾小球细胞外基质改变,免疫组化染色检测增殖细胞核抗原(PCNA)、ED-1及α-SMA在肾小球的表达,同时检测肾皮质超氧化物歧化酶(SOD)活性.结果:Thy 1.1 GN FF组尿蛋白量及三色染色面积均比Thy 1.1 GN组减少(分别P＜0.05和P＜0.01);免疫组化显示PCNA、ED-1阳性细胞数及α-SMA在肾小球表达下调,均与Thy 1.1 GN组有统计学差异(P＜0.01);FF还可加快anti-Thy 1.1 GN模型肾皮质SOD活性的恢复(P＜0.01).结论:FF通过抗氧化活性,抑制大鼠系膜增殖性肾小球肾炎系膜细胞的增殖及基质的增加.     

缬沙坦对Thy1肾炎大鼠肾小球系膜细胞CDK2表达的影响

目的：观察Thy1肾炎大鼠系膜细胞增生及CDK2表达，以及血管紧张素Ⅱ受体拮抗剂缬沙坦对其干预作用。方法：设正常组、Tby1。肾炎组及Tby1肾炎＋缬沙坦治疗组。分别于各组疾病诱导后第1、3、5、7d取。肾脏行病理检查，免疫组化检测肾小球内PCNA、CDK2蛋白的表达，Western blot分析肾小球内CDK2的表达。结果：在正常大鼠系膜细胞CDK2存在低表达，而在肾炎大鼠随系膜细胞增生，其CDK2表达增加。缬沙坦治疗组第3～7d。肾小球系膜细胞增生、系膜区扩张程度以及肾小球内PCNA表达低于。肾炎组（P〈0．05），肾小球内CDK2表达也低于。肾炎组相应时间点（P〈0．05）。结论：。肾小球系膜细胞的增生与其CDK2的高表达相关，缬沙坦可抑制系膜细胞CDK2的高表达，抑制系膜细胞增殖及系膜扩张。提示缬沙坦对Thy1肾炎大鼠有一定治疗作用。     

体外转基因成肌细胞移植对大鼠损伤脊髓细胞凋亡的影响

目的：探讨大鼠脊髓损伤后胚胎脊髓和腺病毒介导的脑源性神经生长因子（AxCA-BDNF)体外转基因成肌细胞移植对大鼠脊髓细胞凋亡的影响。方法：将动物分为：大鼠脊髓半切洞损伤明胶海绵填充组（A组）,大鼠脊髓半切洞损伤应用胚胎脊髓移植组（B组）,脊髓半切洞损伤损伤AxCA-BDNF基因转染的成肌细胞移植组（C组）大鼠脊髓半切洞损伤后应用胚胎脊髓和AxCA-BDNF基因转染的成肌细胞移植组（D组）。手术后1、3、7、14、28d应用行为学和电生理检查观察大鼠功能恢复情况,对脊髓损伤区进行细胞凋亡的检测（TUNEL）以及Bcl-2蛋白表达的测定（免疫组化法）。采用计算机图像分析技术,进行定量分析。结果：A、B、C、D四组中均发现凋亡细胞及Bcl-2蛋白阳性表达细胞,图像分析发现,各组凋亡细胞核为A＞B＞C＞D;Bcl-2免疫反应阳性细胞表达顺序为D＞C＞B＞A,Bcl-2免疫反应阳性细胞的表达与大鼠后肢功能恢复有同样的变化趋势。结论：大鼠胚胎脊髓和体外转基因成肌细胞移植能抑制脊髓损伤后的细胞凋亡。     

坐骨神经损伤对背根节细胞凋亡及细胞凋亡相关蛋白表达的影响

目的：观察大鼠坐骨神经条件性损伤后对背根节细胞凋亡及细胞凋亡相关蛋白表达的影响。方法：将45只成年Wistar大鼠,按手术的不同随机分为3组;正常对照组（A组,n=5）;坐骨神经压榨伤组（B组,n=20);坐骨神经切断组（C组,n=20)。B、C两组又按术后3d,2周,1个月和2个月取材时间分为4个时间组,每组5只大鼠。各时间组取鼠的L5背根神经节后,以TUNEL法检测细胞的凋亡数,以免疫组化技术检测Bcl-2和Bax的表达。结果：正常组及B、C两组伤后3d时未检出凋亡细胞;B、C两组的细胞凋亡率在伤后2周达到高峰,以后随时间的推移而逐渐降低。C组的细胞凋亡率明显高于B组。背根节细胞凋亡相关蛋白Bcl-2及Bax的表达,伤后2周达到高峰。B组中Bcl-2和Bax的表达呈现从低到高而后逐渐恢复正常的规律;而C组的表达始终保持在高水平。结论：细胞凋亡相关蛋白Bcl-2和Bax参与外周神经损伤后背根节细胞凋亡的调节。外周神经的不同损伤方式对背根节细胞凋亡及细胞凋亡相关蛋白的表达影响不同。     

异丙酚对肝移植大鼠肝窦内皮细胞凋亡的影响

目的研究异丙酚对肝移植大鼠肝窦内皮细胞（SEC）凋亡的影响。方法24只健康雄性SD大鼠建立大鼠原位肝移植模型,随机分为3组（n=8）。Ⅰ组（对照组）移植肝再灌注前30min腹腔注射生理盐水15ml/kg；Ⅱ组和Ⅲ组移植肝再灌注前30min分别腹腔注射异丙酚100mg/kg和50mg/ kg。移植肝再灌注6h后取下腔静脉血,测定血浆谷丙转氨酶（ALT）、谷草转氨酶（AST）活性,TUNEL法测定移植肝SEC凋亡,Western blot法测定肝组织Bcl-2及Bax蛋白表达。结果再灌注6h后,与Ⅰ组比较,Ⅱ组、Ⅲ组大鼠血浆ALT、AST活性降低,凋亡SEC减少,Bcl-2蛋白表达上调,Bax蛋白表达下调（P＜0．01）；与Ⅱ组比较,Ⅲ组大鼠血浆ALT、AST活性增高,凋亡SEC增多,Bax蛋白表达上调（P＜0．01）,Bcl-2蛋白表达下调（P＜0．05）。结论异丙酚可剂量依赖性地抑制大鼠移植肝早期再灌注肝窦内皮细胞凋亡,其机制与上调Bcl-2蛋白表达、下调Bax蛋白表达有关。     

手机微波辐射对去颅骨大鼠神经细胞凋亡的影响

目的 研究手机微波辐射对去颅骨大鼠神经细胞凋亡状态的影响。方法 成年雄性SD大鼠80只，随机分为4组：空白组、辐射组、去颅骨组、去颅骨辐射组，每组20只。每天辐射4小时，连续21天，辐射完成后TUNEL法检测凋亡细胞阳性率，用免疫组织化学方法检测辐射后相应时间的脑组织中Bcl-2、BM蛋白的表达情况，并应用SPSSl0．0软件包进行统计分析。结果 去颅骨辐射组TUNEL、Bax、Bcl-2阳性细胞数比去颅骨组TUNEL阳性细胞数有较明显增多，去颅骨辐射组三阳性细胞数与相应的空白组、去颅骨组、辐射组之间均有显性差异。各组的Bax/Bcl-2比值均未见明显异常。结论 微波辐射对完整颅骨大鼠的神经细胞凋亡状态未产生明显影响，而在去颅骨大鼠中则促进了细胞凋亡的发生，Bax、Bcl-2基因与细胞凋亡的发生相关，完整的颅骨为保护神经细胞免受微波辐射损伤的重要因素。     

The mesangial response to injury: Mechanisms of progression and repair

Summary: Mesangial injury accompanies many glomerular diseases and diabetic nephropathy. Whereas in some diseases the injury resolves, in other cases it may progress to sclerosis. We have studied mesangial injury in the Thy 1 model in rats. In this model, the injection of anti-Thy 1 antibody results in complement-mediated killing of <95% of the mesangial cells by 24h. Subsequently there is a migration of mesangial cell 'precursors' from the hilus which proliferate inside the glomerulus to reconstitute the mesangium. Mesangial cell proliferation is dependent on several growth factors, including platelet-derived growth factor (PDGF), basic fibroblast growth factor (bFGF) and endothelin-1, and is accompanied by a phenotypic change of the mesangial cell to a myofibroblast. A transforming growth factor (TGF)-β mediated matrix expansion also occurs. Both the proliferation and matrix expansion subsequently resolve, and the hypercellularity returns to normal by apoptosis. However, if repeated doses of anti-Thy 1 antibody are administered, resolution does not occur and progressive mesangial sclerosis develops. This appears to be mediated by both a lack of proliferation and excess apoptosis, which lead to hypocellularity, and to continued TGF-β expression. Understanding how to prevent these changes could have potential therapeutic impact.     

Pentoxifylline attenuates experimental mesangial proliferative glomerulonephritis.

BACKGROUND: Accumulation of glomerular macrophages, proliferation of mesangial cells (MCs), and deposition of extracellular matrix proteins are pathobiological hallmarks of glomerulonephritis. We previously reported that a clinically available nonselective inhibitor of cyclic 3',5'-nucleotide phosphodiesterase, pentoxifylline (PTX), inhibits proliferation of cultured rat MCs, as well as collagen production by these cells. In this study, we investigated the in vivo effects of PTX on rat anti-Thy1 disease, a model of mesangial proliferative nephritis. METHODS: Anti-Thy1 nephritis was induced in Sprague-Dawley rats by injecting mouse anti-rat Thy1 antibodies intravenously. Nephritic rats were randomly assigned to receive PTX (0.1 g/kg/day) or vehicle (phosphate-buffered saline) and were sacrificed at various time points. Paraffin kidney sections were stained with hematoxylin and periodic acid-Schiff reagents for glomerular histology. Frozen kidney sections were stained by monoclonal antibodies against proliferating cell nuclear antigen, ED-1, and alpha-smooth muscle actin and were visualized by color development from a horseradish peroxidase reaction. Monocyte chemoattractant protein-1 (MCP-1), intercellular adhesion molecule-1 (ICAM-1), and various extracellular matrix mRNAs were analyzed by Northern blotting. Urine protein concentrations were determined by Lowry's method. RESULTS: Nephritic rats treated with PTX excreted less urinary protein on day 5 of nephritis than vehicle-treated nephritic rats. In periodic acid-Schiff-stained kidneys from PTX-treated nephritic rats, there was attenuation of both glomerular cellularity and glomerular sclerosis compared with vehicle-treated nephritic rats. PTX decreased the augmented glomerular mRNA levels of MCP-1 and ICAM-1 at two hours and on day 1 of nephritis. Immunoreactive staining showed that PTX reduced the number of proliferating glomerular macrophages on days 1, 2, and 3, but not at two hours of nephritis, compared with vehicle-treated nephritic rats. On day 5, PTX decreased the number of activated proliferating MCs and attenuated the glomerular mRNA levels of type I (alpha1), type III (alpha1), and type IV (alpha1) collagen and fibronectin compared with vehicle-treated nephritic rats. CONCLUSION: The administration of PTX to rats with anti-Thy1 disease reduces accumulation and proliferation of glomerular macrophages, attenuates proteinuria, suppresses activation and proliferation of MCs, and ameliorates glomerular sclerosis. These results suggest that PTX may have a suppressive effect in acute phases or relapses of mesangial proliferative glomerulonephritis.     

Thrombospondin peptides are potent inhibitors of mesangial and glomerular endothelial cell proliferation in vitro and in vivo.

BACKGROUND: Thrombospondin 1 (TSP1), a multifunctional, matricellular glycoprotein, is expressed de novo in many inflammatory disease processes, including glomerular disease. Short peptide fragments derived from the type I properdin repeats of the TSP1 molecule mimic anti-angiogenic and/or transforming growth factor-beta (TGF-beta)-activating properties of the whole TSP1 glycoprotein. We investigated the effects of D-reverse peptides derived from the type I domain of TSP1 in experimental mesangial proliferative glomerulonephritis in the rat (anti-Thy1 model), as well as their effects on cultured mesangial and glomerular endothelial cells. METHODS: Effects of TSP peptides on proliferation of mesangial or glomerular endothelial cells in culture after growth arrest or growth factor stimulation (fibroblast growth factor-2, platelet-derived growth factor-BB, 10% fetal calf serum) were measured by [3H]thymidine incorporation assay. Adhesion of rat mesangial cells (MCs) to a TSP-peptide matrix was assayed using an attachment-hexosaminidase assay. TSP peptides were intraperitoneally injected daily in rats that had received an intravenous injection of polyclonal anti-Thy1 antibody to induce mesangial proliferative glomerulonephritis. On biopsies from days 2, 5, and 8 of anti-Thy1 disease, mesangial and glomerular endothelial proliferation, matrix expansion, mesangial activation, and microaneurysm formation were assessed. Functional parameters such as blood pressure and proteinuria were also measured. RESULTS: An 18-amino acid peptide (type I peptide) with anti-angiogenic and TGF-beta-activating sequences decreased mesangial and glomerular endothelial cell proliferation in vitro and in vivo and reduced microaneurysm formation and proteinuria in experimental glomerulonephritis. Analogues lacking the TGF-beta-activating sequence mimicked most effects of the type I peptide. The mechanism of action of these peptides may include antagonism of fibroblast growth factor-2 and alteration of MC adhesion. The TGF-beta-activating sequence alone did not have significant effects on mesangial or glomerular endothelial cells in vitro or in experimental kidney disease in vivo. CONCLUSION: Peptides from TSP1 may be promising therapeutics in treating glomerular disease with mesangial and endothelial cell injury.     

P2 receptor antagonist PPADS inhibits mesangial cell proliferation in experimental mesangial proliferative glomerulonephritis

BACKGROUND: Although extracellular nucleotides have been shown to confer mitogenic effects in cultured rat mesangial cells through activation of purinergic P2 receptors (P2Y receptors), thus far the in vivo relevance of these findings is unclear. Virtually all cells and in particular the dense granules of platelets contain high levels of nucleotides that are released upon cell injury or platelet aggregation. In experimental mesangial proliferative glomerulonephritis in the rat (anti-Thy1 model), mesangiolysis and glomerular platelet aggregation are followed by a pronounced mesangial cell (MC) proliferative response leading to glomerular hypercellularity. Therefore, we examined the role of extracellular nucleotides and their corresponding receptors in nucleotide-stimulated cultured mesangial cells and in inflammatory glomerular disease using the P2 receptor antagonist PPADS. METHODS: The effects of PPADS on nucleotide- or fetal calf serum (FCS)-stimulated proliferation of cultured MC were measured by cell counting and [3H]thymidine incorporation assay. After induction of the anti-Thy1 model, rats received injections of the P2-receptor antagonist PPADS at different doses (15, 30, 60 mg/kg BW). Proliferating mesangial and non-mesangial cells, mesangial cell activation, matrix accumulation, influx of inflammatory cells, mesangiolysis, microaneurysm formation, and renal functional parameters were assessed during anti-Thy1 disease. P2Y-mRNA and protein expression was assessed using RT-PCR and real time PCR, Northern blot analysis, in situ hybridization, and immunohistochemistry. RESULTS: In cultured mesangial cells, PPADS inhibited nucleotide, but not FCS-stimulated proliferation in a dose-dependent manner. In the anti-Thy1 model, PPADS specifically and dose-dependently reduced early (day 3), but not late (day 8), glomerular mesangial cell proliferation as well as phenotypic activation of the mesangium and slightly matrix expansion. While no consistent effect was obtained in regard to the degree of mesangiolysis, influx of inflammatory cells, proteinuria or blood pressure, PPADS treatment increased serum creatinine and urea in anti-Thy1 rats. P2Y receptor expression (P2Y2 and P2Y6) was detected in cultured MC and isolated glomeruli, and demonstrated a transient marked increase during anti-Thy1 disease. CONCLUSION: These data strongly suggest an in vivo role for extracellular nucleotides in mediating early MC proliferation after MC injury.     

Transplanted mesenchymal stem cells accelerate glomerular healing in experimental glomerulonephritis

Bone marrow-derived cells contribute to glomerular cell turnover and repair, but the cell types involved are unknown. Whether rat mesenchymal stem cells (MSC) can accelerate recovery from damage in rat mesangioproliferative anti-Thy1.1 glomerulonephritis was studied. After injection into the left renal artery on day 2 after disease induction, fluorescently labeled MSC were detected in 20 to 50% of glomeruli and rare intrarenal vessels but not in the tubulointerstitium, in contralateral kidneys, or in medium controls. In control experiments, injected mesangial cells were detected less frequently in glomeruli in comparison with injected MSC. In nephritic outbred Wistar rats, MSC injection led to an approximately 50% reduction of mesangiolysis on days 4 and 6 after disease induction, accompanied by three- to four-fold higher intraglomerular cell proliferation on day 4 and more rapid mesangial reconstitution as detected by alpha-smooth muscle actin expression. Injection of MSC into tail veins or intra-arterial injection of mesangial cells instead of MSC failed to reproduce any of these findings. In inbred Lewis rats, anti-Thy1.1 nephritis followed an aggravated course with transient acute renal failure. Acute renal failure was ameliorated by MSC injection into the left renal artery on day 2 after disease induction. Again, MSC led to more rapid recovery from mesangiolysis, increased glomerular cell proliferation, and reduction of proteinuria by 28%. Double immunostaining of 5-bromo-2'-deoxyuridine-labeled MSC for endothelial, mesangial, or monocyte/macrophage antigens showed that 85 to 95% of MSC that localized in glomeruli on day 6 failed to express these markers. In vitro, MSC secreted high amounts of vascular endothelial growth factor and TGF-beta1 but not PDGF-BB. In conclusion, even low numbers of MSC can markedly accelerate glomerular recovery from mesangiolytic damage possibly related to paracrine growth factor release and not to differentiation into resident glomerular cell types or monocytes/macrophages.     

Induction of TGF-beta1 by the matricellular protein SPARC in a rat model of glomerulonephritis

Induction of TGF-beta1 by the matricellular protein SPARC in a rat model of glomerulonephritis. BACKGROUND: SPARC has been implicated as a counteradhesive and antiproliferative protein associated with deposits of extracellular matrix in renal disease. METHOD: We have examined the effect of recombinant SPARC containing a C-terminal His tag (rSPARC) in an acute model of mesangial cell injury that is induced in the rat by an antibody against the Thy1 antigen on the mesangial cell membrane. The recombinant protein was administered 24 hours after the induction of nephritis and was infused through day 4. RESULTS: rSPARC was localized to the renal glomeruli of rats treated with anti-Thy1 antibody. Type I collagen and fibronectin, as well as transforming growth factor-beta1 (TGF-beta1), were increased at day 5 in rats treated with rSPARC (N = 4, P < 0.05 vs. delivery buffer), but only minimal effects were seen on mesangial cell and endothelial cell proliferation. In primary cultures of rat mesangial cells, infusion of rSPARC was associated with increases in TGF-beta1 mRNA and in total, secreted TGF-beta1 protein. CONCLUSIONS: rSPARC stimulates expression of TGF-beta1 both in vitro and in vivo. Given the closely regulated expression of SPARC, TGF-beta1, and type I collagen in several animal models of glomerulonephritis, we propose that SPARC could be one of the major mediators of the induction of TGF-beta1 in renal disease.     

Suppressive effects of fish oil on mesangial cell proliferation in vitro and in vivo

BACKGROUND: Mesangial cell proliferation is a characteristic feature of IgA nephropathy and many other forms of glomerulonephritis. Recent clinical studies have shown that dietary fish oil supplementation retards renal disease progression in patients with IgA nephropathy. The mechanism by which this effect occurs is unknown. METHODS: The anti-Thy 1.1 (ATS) model of mesangial proliferative glomerulonephritis was employed to test the hypothesis that dietary fish oil supplementation reduces mesangial cell proliferation following acute injury. Subcultured rat mesangial cells were used to determine the in vitro effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the primary components of fish oil, on proliferation. RESULTS: Following antithymocyte serum (ATS) administration, proteinuria was significantly decreased in animals treated with fish oil compared with sesame oil-treated controls. In ATS rats given fish oil, there was less mesangial cell and matrix expansion, mesangiolysis, or basement membrane disruption (delta% = -40%). ATS rats receiving fish oil had less glomerular cell proliferation (PCNA-delta% = -50%) and a reduction of alpha-smooth muscle actin expression (delta% = -27%) by mesangial cells. In subcultured rat mesangial cells, DHA, but not EPA, significantly inhibited proliferation. CONCLUSIONS: Fish oil inhibits mesangial cell activation and proliferation in ATS glomerulonephritis, reduces proteinuria, and decreases histologic evidence of glomerular damage. In vitro, the antiproliferative effects of fish oil are more likely related to the action of DHA. We suggest that orally administered fish oil, or purified DHA, may have a suppressive effect in acute phases or relapses of glomerulopathies by inhibiting activation and proliferation of mesangial cells.     

Gentamicin treatment induces simultaneous mesangial proliferation and apoptosis in rats

BACKGROUND: Gentamicin (G)-induced acute renal failure is characterized by an impairment of glomerular function without apparent changes in glomerular structure. However, G stimulates reactive oxygen species (ROS)-mediated mesangial cell proliferation in vitro. We studied whether G promotes mesangial cell apoptosis in vitro, and if apoptosis and proliferation in parallel may occur in glomerular cells in vivo after a renal damage induced by G treatment. METHODS: For in vivo studies, rats were treated with G (100 mg/kg body weight/day) for 6 days, and functional and histologic studies were performed. For in vitro studies, mesangial cell proliferation and apoptosis were evaluated after 24, 48, and 72 hours of 10(-5) mol/L G incubation. RESULTS: After G injections, the number of nuclei per glomerulus did not change, whereas proliferating and apoptotic cell numbers increased. G increases DNA synthesis and cell number in cultured mesangial cells, and increases markedly the apoptotic cell number. ROS scavengers superoxide dismutase and catalase reduce G-induced mesangial cell apoptosis, whereas the incubation with the ROS donor system xanthine plus xanthine oxidase increases apoptosis to levels similar to G. G-induced cellular proliferation and apoptosis either in vitro or in vivo is associated to an early increase in the pro-apoptotic protein Bax and a delayed increase in the survival protein Bcl-2. CONCLUSION: G simultaneously induces proliferation and apoptosis of mesangial cells in vitro and glomerular mesangial cells in vivo. ROS may mediate G-induced mesangial apoptosis in vitro. The equilibrium proliferation/apoptosis may maintain mesangial cell number within normal limits after a G-induced glomerular insult.     

Proinflammatory effects in experimental mesangial proliferative glomerulonephritis of the immunosuppressive agent SDZ RAD, a rapamycin derivative

BACKGROUND/AIM: The new immunosuppressant SDZ RAD, a rapamycin derivative, inhibits growth factor driven cell proliferation. SDZ RAD designed for transplantation may also be a candidate agent to treat inflammatory kidney diseases. Therefore, we investigated the effects of SDZ RAD in two different animal models of glomerulonephritis, in anti- Thy1.1 nephritis and in acute puromycin aminonucleoside (PAN) nephrosis. METHODS: Eighty-seven male Wistar rats were investigated. Anti-Thy1.1 nephritis: healthy rats (n = 9), SDZ RAD-treated healthy rats (n = 6), nephritic rats (n = 9), SDZ RAD placebo treated nephritic rats (n = 6), SDZ RAD-pretreated nephritic rats (n = 9), and early (n = 6) as well as delayed (n = 6) SDZ RAD-posttreated nephritic rats. PAN nephrosis: healthy rats (n = 6), SDZ RAD-treated healthy rats (n = 6), nephritic rats (n = 12), and SDZ RAD-pretreated nephritic rats (n = 12). In a separate study, 12 male Sprague-Dawley rats were analyzed in anti-Thy1.1 nephritis: healthy rats (n = 3), nephritic rats (n = 3) and pretreated nephritic rats (n = 6). SDZ RAD and SDZ RAD placebo were given at single doses of 2.5 mg/kg body weight per day by gavage. The experiments lasted until days +2 and +9 after induction of anti-Thy1. 1 nephritis and until day +13 in the case of PAN nephrosis. RESULTS: In anti-Thy1.1 nephritis, SDZ RAD demonstrated marked proinflammatory effects in a time-dependent manner, as reflected by severe focal damage to glomerular histology including inhibition of mesangial cell proliferation, reduction of creatinine clearance, and increase in plasma creatinine levels as well as proteinuria. Almost identical results were obtained in both rat strains. In contrary, SDZ RAD ameliorated significantly the development of PAN nephrosis. Animals pretreated by this agent showed a significant reduction of proteinuria and of glomerular invasion of monocytes/macrophages. CONCLUSION: Some caution is warranted for the use of SDZ RAD in inflammatory glomerular diseases, since it accentuated glomerular damage induced by anti-Thy1.1 antibodies.