红细胞生成素对高糖诱导肾小管细胞凋亡的影响

目的 探讨红细胞生成素（EPO）是否可以抑制高糖诱导的大鼠近端肾小管上皮细胞凋亡及其相关机制。 方法 传代培养大鼠近端肾小管上皮细胞（NRK-52E）,分为正常对照组（NC组）、渗透浓度对照组（OC组）、高糖组（HG组）、高糖+EPO 50 U/ml组（E1组）和高糖+EPO 100 U/ml组（E2组）。免疫荧光检测NRK-52E细胞有无EPO受体（EPOR）表达。Western印迹检测高糖对EPOR表达的影响。流式细胞仪Annexin V-FITC/PI双染法检测细胞凋亡指数。荧光探针CM-H2DCFDA检测细胞内活性氧（ROS）的水平。RT-PCR检测bcl-2、bax、capases-3 mRNA的表达。 结果 （1）NRK-52E细胞表达EPOR,且高糖可刺激EPOR表达增加。（2）高糖可诱导NRK-52E细胞凋亡,与葡萄糖相同渗透浓度的甘露醇不能明显诱导细胞凋亡。E1、E2组细胞早、晚期凋亡率显著低于HG组（P < 0.05）。（3）高糖刺激 NRK-52E细胞后,细胞内ROS产生增多,bcl-2 mRNA的表达下调,bax、caspase-3 mRNA的表达上调。EPO可以抑制细胞内ROS的产生,上调bcl-2 mRNA 表达,下调bax、caspase-3 mRNA 表达。 结论 EPO可能通过EPOR的介导,缓解高糖诱导的氧化应激,上调bcl-2 mRNA表达,下调bax、caspase-3 mRNA表达,抑制NRK-52E细胞凋亡。     

血管紧张素Ⅱ灌注诱导nephrin表达改变与足细胞凋亡

目的 研究血管紧张素Ⅱ（AngⅡ）灌注对大鼠足细胞裂隙膜分子nephrin表达及足细胞凋亡的影响，以及探讨AngⅡ引起蛋白尿及肾小球硬化的机制。方法 36只雄性Sprague Dawley大鼠分为AngⅡ灌注组(400 ng&#8226;kg-1&#8226;min-1)、生理盐水灌注组和正常对照组，测定28 d内大鼠血压及尿蛋白。分别于14、28 d处死动物取肾，观察组织学改变，并用免疫荧光、免疫电镜检测nephrin分布。RT-PCR及Western印迹法分别检测nephrin mRNA及蛋白表达。TUNEL法检测足细胞凋亡。结果 (1) AngⅡ灌注组大鼠血压升高，14 d达峰值并维持该水平至28 d；AngⅡ灌注7 d即出现蛋白尿，并持续增加。(2) AngⅡ灌注14 d时，足细胞裂隙膜变窄；灌注28 d时，足突增宽及节段性融合，部分足细胞有凋亡小体形成，少数肾小球出现节段性硬化。TUNEL法检测发现足细胞凋亡[（2.7±1.6）个/肾小球切面]，凋亡数与蛋白尿量呈正相关（r = 0.86，P < 0.01）。(3) AngⅡ灌注14 d时，肾皮质nephrin mRNA及蛋白表达上调（P < 0.05）。nephrin由正常的沿毛细血管袢线状分布向粗颗粒、团块状分布模式转变。AngⅡ灌注28 d时，肾皮质nephrin mRNA及蛋白表达下降（P < 0.05），且nephrin蛋白表达与足细胞凋亡数呈负相关（r = －0.63，P < 0.01）。 结论 AngⅡ灌注诱导的nephrin表达及分布改变可能导致了足细胞凋亡及肾小球硬化的发生与发展。     

醛固酮抑制Akt活性诱导大鼠足细胞凋亡

目的 探讨醛固酮(ALD)能否诱导培养大鼠足细胞凋亡及Akt信号通路是否参与ALD诱导的足细胞凋亡。方法 体外培养并鉴定大鼠足细胞。无血清同步化处理24 h，分别给予终浓度为0(对照组)、10-9~10-5 mol/L ALD，伴或不伴螺内酯(10-7 mol/L)共孵育。流式细胞仪检测凋亡指数，Hoechst-33342染色检测足细胞凋亡。多聚酶链反应(RT-PCR)检测足细胞盐皮质激素受体(MR)和11β-羟类固醇脱氢酶2 (11β-HSD2) mRNA表达。Akt活性检测试剂盒检测Akt活性表达。结果 ALD以时间和剂量依赖方式诱导足细胞凋亡。螺内酯可明显抑制ALD诱导的足细胞凋亡[ALD+螺内酯组(5.61%±0.72%)比ALD组(15.10%±1.46%)，P < 0.05]。RT-PCR结果证实足细胞表达MR和11β-HSD2 mRNA。螺内酯可部分阻断ALD对Akt活性的抑制作用。ALD诱导的足细胞凋亡率与Akt活性呈明显负相关(r=-0.77， P < 0.05)。结论 ALD可诱导大鼠足细胞凋亡，Akt活性下降可能参与ALD诱导的足细胞凋亡。     

醛固酮通过转化生长因子β1途径调节足细胞基质金属蛋白酶2和9表达

目的 观察醛固酮（ALD）刺激对足细胞培养上清液中基质金属蛋白酶2、9（MMP-2、MMP-9）活性、Ⅳ型胶原的影响及探讨ALD对足细胞细胞外基质分泌、降解的调节机制。 方法 分别用不同浓度ALD（10－11、10－9、10－7 mol/L）以不同时间（24、48、72 h）作用足细胞,并设立空白对照组。用明胶酶谱、Western印迹、ELISA方法检测培养上清液中MMP-2、MMP-9、Ⅳ型胶原α5链及TGF-β1;流式细胞仪检测足细胞黏附率,同时观察ALD受体拮抗剂螺内酯（SPI）及TGF-β1受体抑制剂对上述效应的阻断作用。 结果 与对照组相比,ALD以时间及剂量依赖性导致培养上清液中MMP-2、MMP-9活性升高（P < 0.05）;Ⅳ型胶原α5链蛋白表达下降（P < 0.05）;TGF-β1蛋白表达升高（P < 0.05）。SPI可完全阻断,而TGF-β1受体抑制剂SB431542可部分阻断ALD刺激足细胞引起的MMP-2、MMP-9活性升高、Ⅳ型胶原α5链蛋白及足细胞黏附率的下降（P < 0.05）。 结论 ALD通过TGF-β1途径使足细胞MMP-2、MMP-9活性升高,Ⅳ型胶原α5链蛋白表达下降,足细胞黏附率下降,从而使足细胞分泌基底膜成分异常,基底膜合成及降解失衡,导致足细胞损伤。     

nephrin通过PI3K-Akt途径抑制血管紧张素Ⅱ诱导的足细胞凋亡

目的 研究nephrin在血管紧张素Ⅱ（AngⅡ）诱导足细胞凋亡中的作用,以及可能的分子机制。 方法 体外培养永生化小鼠足细胞（MPC）,以不同浓度AngⅡ处理MPC和10-8 mol/L AngⅡ刺激不同时间,用流式细胞仪检测细胞凋亡率;实时定量PCR、免疫荧光和Western印迹法检测nephrin的表达和分布;Western印迹法检测Akt磷酸化水平。脂质体法转染pcDNA3.1-mNPHS1质粒,G418筛选稳定转染细胞系。用Akt抑制剂LY294002或与AngⅡ共孵育刺激MPC和pcDNA3.1-mNPHS1转染细胞,检测Akt磷酸化水平和细胞凋亡率。 结果 （1）AngⅡ以剂量和时间依赖方式诱导MPC凋亡。AngⅡ受体拮抗药氯沙坦与AngⅡ共孵育18 h,显著降低AngⅡ单独刺激的足细胞凋亡率（P < 0.05）。（2）10-8 mol/L AngⅡ刺激12 h后,nephrin mRNA和蛋白较对照组显著降低,24 h nephrin mRNA约为正常对照的50%（P < 0.05）。正常足细胞nephrin主要分布于核膜周围的胞质和细胞膜,随刺激时间延长,胞膜和胞质nephrin表达逐渐降低。（3）10-8 mol/L AngⅡ刺激15 min后,Akt磷酸化显著降低,约为正常对照细胞的50%（P < 0.01）。（4）AngⅡ与LY294002共孵育12 h后,细胞凋亡率显著高于AngⅡ和LY294002单独刺激（均P < 0.05）。（5）pcDNA3.1-mNPHS1稳定转染显著上调足细胞Akt磷酸化水平（P < 0.05）,抑制 AngⅡ诱导的细胞凋亡（P < 0.05）。 结论 AngⅡ通过AngⅡ受体诱导小鼠足细胞凋亡,抑制足细胞nephrin表达。nephrin通过PI3K-Akt信号通路调节足细胞存活状态。     

N-乙酰半胱氨酸对糖尿病肾病大鼠足细胞的保护作用

目的：探讨N-乙酰半胱氨酸（NAC）对糖尿病肾病（DN）大鼠足细胞的保护作用。方法：制备DN大鼠模型,将动物随机分为正常对照组、DN组和NAC组。8周后观察尿蛋白排泄量,免疫荧光方法和Western blotting检测肾皮质nephrin和podocin蛋白表达,透射电镜检测足细胞超微结构变化。结果：（1）与正常对照组比较,DN组和NAC组尿白蛋白排泄率增多（P〈0.01）,nephrin和podocin蛋白表达减少（P〈0.01或P〈0.05）和肾脏病理病变明显;（2）与DN组比较,NAC组尿蛋白排泄减少（P〈0.01）,nephrin和podocin蛋白表达较高（P〈0.01或P〈0.05）和足细胞的病变较轻。结论：NAC对DN大鼠肾脏保护作用,其部分机制与上调nephrin和podocin蛋白表达及改善足细胞病变有关。     

3，4-二羟基苯甲酸乙酯预处理对白蛋白诱导低氧培养肾小管上皮细胞凋亡的影响

目的 探讨脯胺酰羟化酶抑制剂3,4-二羟基苯甲酸乙酯（EDHB）对白蛋白诱导的低氧条件下培养的肾小管上皮细胞（NRK-52E）凋亡的影响。 方法 NRK-52E细胞在以下各组孵育24 h：常氧（5％CO2+空气）组,低氧（1％O2+5％CO2+94％N2）组,常氧+白蛋白（30 g/L）组及低氧+白蛋白（30 g/L）组,观察各组NRK-52E细胞的凋亡情况。然后NRK-52E细胞在以下各组孵育24 h：常氧组、低氧组,低氧+白蛋白（30 g/L）组,低氧+EDHB（500 μmol/L）组,EDHB预处理组（培养细胞中先加入EDHB 500 μmol/L,0.5 h后再加入BSA 30 g/L,低氧培养）,观察EDHB对白蛋白诱导低氧培养NRK-52E凋亡的影响。流式细胞技术检测细胞凋亡;RT-PCR检测凋亡相关蛋白bcl-2、bax 及血管内皮生长因子（VEGF）mRNA表达;Western印迹检测VEGF蛋白表达。 结果 NRK-52E细胞凋亡率在常氧组与低氧组差异无统计学意义 （P > 0.05）,但低氧+白蛋白组细胞凋亡率显著高于常氧+白蛋白组（37.36%±4.95%比25.59%±3.32%,P < 0.05）。低氧+白蛋白组bax mRNA表达显著高于常氧+白蛋白组（P < 0.05）,而bcl-2 mRNA的表达则显著低于常氧+白蛋白组（P < 0.05）。EDHB预处理可显著抑制低氧+白蛋白组细胞凋亡率的增高（P < 0.05）、bax mRNA表达的增高（P < 0.05）以及bcl-2 mRNA表达的降低（P < 0.05）。低氧组NRK-52E细胞VEGF mRNA和蛋白表达显著高于常氧组（P < 0.05）,而低氧+白蛋白组则显著低于低氧组（P < 0.05）。EDHB预处理可显著抑制低氧+白蛋白组细胞VEGF mRNA和蛋白表达的降低（P < 0.05）。 结论 白蛋白和低氧联合刺激可显著增加NRK-52E细胞凋亡,EDHB预处理可改善该病变,可能与其提高VEGF的表达有关。     

不同降压药对醛固酮输注大鼠足细胞损伤的影响

目的 研究醛固酮（ALD）对肾小球足细胞的损伤作用并探讨醛固酮拮抗剂依普利酮（EPL）、氨氯地平（CCB）和替米沙坦（ARB）对ALD所致损伤的影响及机制。 方法 30只SD大鼠被随机分为对照组（CTL组）、ALD输注组以及ALD输注并用EPL、CCB或ARB治疗组。以1.5 μg/h输注ALD造模，用EPL（100 mg·kg-1·d-1）、CCB（10 mg·kg-1·d-1） 和ARB（3 mg·kg-1·d-1）分别灌胃治疗。检测28 d内血压及尿白蛋白排泄率（UAER）。于28 d处死动物，检测血浆ALD、AngⅡ、血钾、钠、Scr；观察肾脏光镜和电镜病理改变；TUNEL法检测细胞凋亡；免疫组化和RT-PCR法检测nephrin表达。 结果 （1）与CTL组相比，ALD组大鼠7 d时血压开始升高，28 d达高峰（P < 0.01）；EPL组血压和UAER均显著低于同时间点ALD组（P < 0.01）；CCB组UAER显著高于同时间点EPL组，但与ALD组差异无统计学意义。（2）ARB组血浆AngⅡ水平显著高于ALD组、CCB组和EPL组（P < 0.01）。（3）ALD组肾小球出现系膜细胞增殖、系膜外基质增多、足突融合和微绒毛化等病理改变。EPL组肾小球损伤评分和凋亡率显著低于ALD组、CCB组和ARB组（分别P < 0.05，P < 0.01）。（4）ALD组nephrin mRNA和蛋白表达均高于CTL组，EPL组nephrin蛋白和mRNA表达低于ALD组（P < 0.01）。 结论 ALD输注可诱导肾小球足细胞损伤。CCB和ARB能显著降低血压，但不能减轻ALD所致损伤。EPL可通过非血流动力学作用部分阻断ALD的损伤效应。     

垂体中叶素对肾脏缺血再灌注大鼠肾小管上皮细胞凋亡的影响及其机制

目的 探讨垂体中叶素（IMD）对肾脏缺血再灌注（I/R）大鼠肾小管上皮细胞凋亡的影响及相关机制。 方法 健康雄性Wistar大鼠24只随机分为假手术组、I/R组、空质粒组、IMD质粒组。动物右肾切除后,采用超声微泡法,将空质粒或IMD质粒转染入左肾,1周后制作肾脏I/R模型。TUNEL法测定细胞凋亡;半定量RT-PCR检测Bax、Bcl-2、Fas的mRNA表达水平;比色法检测caspase-8、-9的活性;Western印迹法检测caspase-3蛋白的表达水平。 结果 与假手术组相比,I/R组细胞凋亡率增高,Bax、Fas mRNA表达增加,bcl-2 mRNA表达下降,caspase-8、-9活性增强,caspase-3蛋白表达增加（均P < 0.05）。与I/R组相比,IMD转染组细胞凋亡率明显降低,Bax、Fas的mRNA表达下降,bcl-2的mRNA表达增加,caspase-8、-9活性减弱,caspase-3蛋白表达减少（均P < 0.05）。转空质粒组与I/R组比较,各指标差异均无统计学意义。 结论 IMD能上调bcl-2表达,降低bax、Fas的表达,降低caspase-8、-9活性,从而抑制肾脏I/R损伤所诱导的凋亡。     

N-乙酰半胱氨酸对碘海醇诱导肾小管上皮细胞损伤的保护作用

目的 探讨N-乙酰半胱氨酸（NAC）对碘海醇引起人肾小管上皮细胞（HK-2）损伤的保护作用及机制。 方法 将体外培养的HK-2细胞分为4组：对照组、碘海醇组、NAC组、NAC预处理＋碘海醇共作用组。用细胞增殖/毒性检测法（CCK-8）测定细胞存活率;核染色、AnnexinⅤ-FITC/PI双染法检测细胞凋亡;二氯二氢荧光素双醋酸盐（DCFH-DA）荧光结合流式细胞法检测细胞内活性氧（ROS）的产生;免疫荧光（IF）、Western印迹法检测相关信号转导途径。 结果 碘海醇呈剂量和时间依赖性诱导HK-2细胞凋亡,降低细胞存活率。碘海醇使细胞内ROS升高至对照组的1.3倍。NAC（5、10、15 mmol/L）预处理与碘海醇共作用后, HK-2细胞存活率分别增至104%、118%、130%,与碘海醇组（63%）差异有统计学意义（P < 0.05）;凋亡率分别降为13.51%、13.46%、12.23%,与碘海醇组（24.41%）差异亦有统计学意义（P < 0.05）;活性氧分别降为对照组的1.05、0.93、0.86倍,与碘海醇组（对照组的1.3倍）差异亦有统计学意义（P < 0.05）。碘海醇作用于HK-2细胞,引起p53磷酸化,上调Bax,下调Bcl-2的表达,促进线粒体内细胞色素C（CytC）释放到胞质,进而引起半胱天冬氨酸蛋白酶（caspase）-3活化,导致细胞凋亡。NAC降低细胞内ROS浓度,下调Bax表达,上调Bcl-2表达,减少caspase-3活化,从而减轻细胞损伤。 结论 碘海醇增加细胞内ROS生成,引起p53磷酸化,进而影响Bcl-2家族蛋白表达,促进CytC从线粒体释放和激活caspase-3信号通路,导致细胞凋亡。NAC通过清除氧自由基,降低细胞内ROS浓度,进而减轻碘海醇诱导的氧化应激所致细胞损伤及凋亡。     

马兜铃酸损伤大鼠肾小球足细胞的研究

目的 探讨马兜铃酸是否能损害肾小球足细胞.方法 用关木通浸膏水溶液间断灌胃制作马兜铃酸肾损害大鼠模型,分别于第1、4周末检测早期马兜铃酸肾损害大鼠24 h尿蛋白量,并以十二烷基磺酸钠-聚丙烯酰胺凝胶电泳观察尿蛋白成分.随后处死大鼠取肾组织,用激光显微切割捕获技术分离肾小球;用实时荧光定量PCR检测肾小球中nephnn、podocin、CD2AP、podocalyxin、podoplanin的mRNA表达;电镜下测量肾小球足突的平均宽度.结果 模型大鼠4周末尿蛋白量较对照组显着增多(P＜0.01),其中白蛋白含量明显增加.电镜结果显示肾小球足突平均宽度较对照组显著增宽(P＜0.01).肾小球中nephrin、podocin、CD2AP、podocalyxin、podoplanin的mRNA表达均较对照组显著减少,分别下调34％、62％、56％、50％(P＜0.01)及27％(P＜0.05).结论 马兜铃酸能损伤肾小球足细胞,导致足细胞相关蛋白mRNA表达下调,足突节段增宽,并出现白蛋白尿.     

Effect of aggregated immunoglobulin A1 from immunoglobulin A nephropathy patients on nephrin expression in podocytes

Aim: Abnormal immunoglobulin (Ig)A1 is considered to play a pivotal role in IgA nephropathy. We used mouse podocytes as the experimental model to investigate the effect of aggregated IgA1 (aIgA1) isolated from IgA nephropathy (IgAN) patients on nephrin expression in podocytes through direct and indirect pathways. Methods: Jacalin affinity chromatography and Sephacryl S‐200 molecular sieve chromatography were used to isolate IgA1 from blood of IgAN patients which was therefore became aIgA1. Podocytes were incubated with aIgA1 or special mesangial medium. Nephrin expression in podocytes was measured by real‐time polymerase chain reaction and western blot analysis. Results: Aggregated IgA1 from IgAN patients and healthy controls reduced nephrin expression in podocytes at mRNA and protein levels when compared with podocytes incubated with control medium (RPMI‐1640 with 0.5% foetal bovine serum) (P < 0.05). While medium from mesangial cells incubated with aIgA1 from IgAN inhibited nephrin expression in podocytes at mRNA and protein levels when compared with podocytes incubated with medium from mesangial cells with aIgA1 from healthy controls (P < 0.05). Conclusion: Our findings implicate that aIgA1 from IgAN patients could inhibit nephrin expression through direct and indirect pathways, although these mechanisms remain to be clarified.     

AGE与RAGE相互作用通过活性氧引起足细胞凋亡

目的：探讨晚期糖基化终末产物（AGE）对足细胞凋亡的影响,及氧化应激在其中的作用。方法：小鼠足细胞株由美国纽约西奈山医学院Peter Mundel教授馈赠。用钙磷脂结合蛋白Ⅴ-荧光异硫氰酸盐（FITC）和碘化物（PI）标记细胞,采用荧光激活细胞分类（FACS）法来计数凋亡和坏死的足细胞。Dharmacon On TargetPlus SMARTpool si RNA试剂和Amaxa RNAi nucleofection试剂盒成功转染si RNA到足细胞。绿荧光蛋白载体证明转染的有效性,分别采用Western Blot和实时定量PCR（RT-PCR）方法来检测si RNA转染足细胞后AGE受体蛋白（RAGE）靶基因蛋白质和mRNA的表达。用LS50B型荧光分光光度计测活性氧,根据波长485nm在530nm发射的荧光来判断活性氧（ROS）的产生。观察活性氧的清除剂N-乙酰基-半胱氨酸（NAC）能否减少AGE-BSA诱导的足细胞凋亡。结果：AGE引起足细胞的凋亡呈剂量依赖性,随AGE浓度的增大,凋亡的发生率逐渐升高;RAGE siRNA能减少60%~70%RAGE mRNA和蛋白质的表达;ROS的清除剂NAC可明显减少AGE-BSA引起的ROS的产生和足细胞凋亡。结论：AGE与RAGE作用后活性氧产生增加,活性氧的增加可能是AGE引起足细胞凋亡的途径之一,可通过抗氧化减少ROS的产生延缓糖尿病肾病的进展。     

缺氧诱导因子-1α对体外模拟CO2气腹下人胃癌细胞凋亡的影响

目的 通过体外模拟CO2气腹环境,构建沉默缺氧诱导因子-1α(HIF-1α)的RNAi表达载体,探讨HIF-1α对CO2气腹环境下人胃癌细胞MKN-45凋亡的影响及机制.方法 利用密闭培养箱模拟CO2气腹,气腹机维持培养箱内压力分别为0、5、10、15 mm Hg(1 mm Hg=0.133 kPa),采用RT-PCR方法和Western blot方法观察沉默HIF-1α前后MKN-45细胞HIF-1α mRNA和蛋白表达变化.免疫组化技术观察沉默HIF-1α前后细胞bcl-2/bax表达变化.Annexin V-FITC/PI舣标染色、流式细胞仪检测沉默HIF-1α前后细胞凋亡比例变化.结果 沉默HIF-1α前15 mm Hg组细胞HIF-1α mRNA和蛋白表达(1.48±0.22和1.34±0.09)以及10 nnn Hg组细胞蛋门表达(1.25±0.10)均显著高于对照组(0.55±0.17和0.83±0.04)(P＜0.05).0、5、10 mm Hg组细胞HIF-1α mRNA和0、5 mm Hg蛋白表达与对照组比较差异无统计学意义(P＞0.05).沉默HIF-1α前15 mm Hg组细胞bcl-2/bax比值(0.78±0.05)较对照组(1.43±0.15)明显降低(P＜0.05),细胞凋亡比例(11.70±0.12)较对照组(0.22±0.07)显著增加(P＜0.01).而在沉默HIF-1α后15 mm Hg组细胞HIF-1α mRNA表达(0.52±0.11)和蛋白表达(0.92±0.02)、bcl-2/bax比值(1.57±0.04)、细胞凋亡比例(0.45±0.11)与对照组比较均无显著差异(P＞0.05).结论 在CO2气腹环境压力为0、5、10 mmHg CO2时MKN-45细胞凋亡比例与对照组比较无显著差异,压力为15 mm Hg时CO2气腹可促进胃癌细胞凋亡,HIF-1α可能为促进细胞凋亡的重要因子.     

EP1 receptor mediates Adriamycin-induced podocyte injury through activating p38 MAPK

Objective To investigate the effect of prostaglandin E2 receptor 1 (EP1) on Adriamycin (ADR)-induced glomerular podocytes injury and its possible mechanism. Methods (1) In vivo experiments: 6-8 weeks old male Balb/c mice were randomly divided into four groups: Control group; ADR group; EP1 agonist 17-phenyl PGE2+ADR group; EP1 antagonist SC-19220+ADR group. The mouse model of nephrotic syndrome was induced by injection of ADR (10 mg/kg) into tail vein, and then EP1 agonist (1 μg/g) and antagonist (25 μg/g) were administered respectively. Six weeks later, all mice were sacrificed and urine, blood and kidney tissues were collected. Detecting urine protein, blood chemistry, changes of renal pathology and podocyte-related proteins, electron microscopy changes of podocytes. (2) In vitro experiments: Podocytes were cultured in vitro and divided into different groups: Control group; ADR group (0.2 μmol/L); EP1 agonist (0.1, 1, 10 μmol/L)+ADR (0.2 μmol/L) group; antagonist (0.1, 0.5, 1 μmol/L)+ADR (0.2 μmol/L) group. The proliferation of podocytes was measured by CCK-8. Expression of PGE2 in podocytes was detected by ELISA. Indirect immunofluorescence was used to determine the localization of podocyte-related proteins nephrin, podocin and CD2AP. Expression of nephrin, podocin, CD2AP, COX2 in podocytes was detected by Western blotting and Real-time quantitative PCR. p38 MAPK or phospho-p38 MAPK was measured by Western blotting as well. Flow cytometry was used to detect cell apoptosis. Results (1) In vivo experiments: Compared with control group, obvious proteinuria, blood biochemical changes and renal pathological changes were observed in ADR group, proteinuria, blood biochemical and renal pathological changes were more serious in mice dealt with agonist, while antagonist could reduce ADR-induced injury (all P＜0.05). Results of immunohistochemistry showed that the expression of podocyte-related proteins nephrin, podocin and CD2AP in ADR group were significantly lower than those in control group, and EP1 agonist could further inhibit expression of these proteins, while antagonist could reverse this inhibitory effects (P＜0.05). Electron microscopic results showed that mice in ADR group appeared foot enlargement and fusion, and the agonist group further aggravated the injury, while antagonist intervention could inhibit the injury of podocytes. (2) In vitro experiments: Compared with control group, expression of PGE2 and COX2 were increased; mRNA and protein expression of nephrin, podocin, CD2AP were decreased, p38 MAPK activity and podocytes apoptosis were increased in ADR group (P＜0.05); Agonist could aggravate podocytes damage (P＜0.05), while Antagonist could down-regulate the expression of PGE2 and COX2, promote the expression of nephrin, podocin and CD2AP, and inhibit the activity of p38 MAPK and podocytes apoptosis (P＜0.05). The addition of p38 MAPK inhibitor(10 μmol/L) could reduce the inhibitory effect of EP1 agonist on the expression of podocyte-related proteins nephrin, podocin and CD2AP (P＜0.05). Conclusions EP1 receptor may activate the p38 MAPK signaling pathway to inhibit podocytes-related proteins nephrin, podocin and CD2AP, as well as mediate the ADR induced podocyte injury. Inhibition of EP1 receptor however have a protective effect.     

Bufalin alleviates adriamycin-induced podocyte injury by up-regulating the expression of vitamin D receptor

Objective To investigate the role of vitamin D receptor (VDR) in the protection of bufalin on podocyte injury induced by adriamycin (ADR). Methods (1) In vitro: the toxic effect of different concentrations of bufalin (10-9, 10-8, 10-7, 10-6 mol/L) on podocyte was evaluated by lactate dehydrogenase (LDH) test;Annexin V-FITC and RT-PCR were utilized for podocyte apoptosis and VDR mRNA level respectively. Western blotting was used to analyze the protein expression of VDR and nephrin. SiRNA intervene was also applied to evaluate the role of VDR in bufalin's protective effect on podocyte injury induced by ADR. (2) In vitro: 24 SD rats were randomly divided into three groups: control group, ADR group and ADR+bufalin group. TUNEL assay was applied to detect the apoptosis of podocytes in the kidney. Immunofluorescence and transmission electron microscope (TEM) were applied to analyze the expression of VDR and the ultrastructure of the glomerulus. Results Bufalin concentration lower than 10-7 mol/L had no toxicity on normal podocyte. Bufalin reduced the urinary protein excretion (P＜0.05), alleviated the removal of podocyte foot processes and attenuated the changes in nephrin expression in the glomerulus of the adriamycin (ADR) rats (P＜0.05). Bufalin notably inhibited the down-regulation of VDR in protein levels on the glomerulus of the ADR rats. Additionally, bufalin inhibited the down-regulation of VDR in both mRNA levels and protein levels (P＜0.05）, nephrin protein expression (P＜0.05), and apoptosis induced by ADR in cultured podocytes. Additionally, VDR specific siRNA intervene abolished the protective effect of bufalin in ADR-induced podocyte injury. Conclusion Bufalin can alleviate ADR-induced podocyte injury via enhancing VDR expression.     

生长抑素抑制人结肠癌细胞增殖的实验研究

目的：研究外源性生长激素（GH）和生长抑素（SS）对人结肠癌细胞株HT-29的影响，并探讨其作用机制。方法：人结肠癌细胞株HT-29分成正常对照组、生长抑素组（SS组）、生长激素组（GH组）和生长抑素＋生长激素组（GH＋SS组）。MTT法测定细胞抑制率，流式细胞仪测定细胞周期分布、增殖指数、凋亡率，RT—PCR方法测定bcl．2及baxmRNA水平。结果：生长抑素能够明显抑制人结肠癌细胞株HT-29增殖（P〈0．01）、降低S期和G2／M期细胞比例（P〈0．05）、降低增殖指数（PI）（P〈0．05）、促进细胞凋亡（P〈0．01）、降低bcl-2mRNA表达（P〈0．05）、提高baxmRNA表达（P〈0．01），生长激素则无明显作用。GH＋SS组表现与SS组相似。结论：生长抑素可能通过抑制GdG．期细胞进入S期和G2／M期以及促进细胞凋亡两种途径抑制体外培养的人结肠癌细胞株HT-29增殖。生长抑素可能是通过改变bax基因和bcl-2基因的表达影响肿瘤细胞的凋亡。生长激素对体外培养的人结肠癌细胞株HT-29无显著影响。     

Early autophagy activation inhibits podocytes from apoptosis induced by aldosterone

Objective To explore the protection of early autophagy activation on podocyte injury induced by aldosterone. Methods In vitro cultured mouse podocyte clones (MPC5) were treated with aldosterone for 6, 12, 24, 48 h respectively. Apoptosis of podocytes was detected by Annexin V combined with flow cytometry. After 24 h treatment with aldosterone, the existence of apoptotic body and autophagosome was observed by electron microscopy. The protein expressions of LC3, caspase?3 and nephrin were examined by Western blotting. The mRNA expression of Beclin?1 was detected by real?time PCR. Results The induction of apoptosis and autophagy by aldosterone in podocytes was in time?dependent mannner. After 24 h treatment with aldosterone, the apoptosis was increased by 26.5% (P＜0.05) and the expression of nephrin was decreased by 28.0% (P＜0.05) compared to control group. Aldosterone remarkably induced the expression of Beclin?1 at 6 h and promoted the transformation of LC3?Ⅰto LC3?Ⅱ at 12 h (P＜0.05). Compared to simple aldosterone treatment, the apoptosis rate of podocyte was increased by 39.0%（P＜0.05）and the expression of nephrin was declined by 19.5%（P＜0.05) after 3?methyladenine (3?MA) pre?treatment. Conclusions Aldosterone can induce autophagy and apoptosis in podocytes. Autophagy occurs earlier (12 h) than apoptosis (24 h). The occurrence of autophagy can inhibit the apoptosis,so the autophagy pathway may be a new research topic of glomerular disease treatment.