衰老大鼠肾小管间质细胞表型转化及意义

目的通过检测肾小管间质细胞表型转化的标志物,明确其在肾脏衰老过程中的意义.方法选用3月、12月与24月Wistar大鼠,采用免疫组化方法检测肾小管间质中细胞表型标志α平滑肌肌动蛋白(α-SMA),细胞增殖标志.增殖性细胞核抗原(PCNA)与细胞外基质[Ⅰ型胶原、Ⅲ型胶原、纤连蛋白(FN)]在不同月龄大鼠肾小管间质中的表达.采用真彩医学图像分析系统进行定量分析.结果肾小管间质随增龄出现明显的病理变化.24月龄大鼠肾间质中α-SMA表达明显增多,而在3月龄除血管平滑肌外未见间质中阳性表达.PCNA在12月龄表达最为明显,与3月龄与24月龄存在显著性差异(P＜0.05).肾小管间质中细胞外基质Ⅰ型胶原、Ⅲ型胶原及FN随着增龄表达明显增加,24月龄与3月龄及12月龄相比存在显著性差异(均P＜0.05).Ⅰ型胶原、FN与间质纤维化程度呈正相关(r=0.63与r=0.78,均P＜0.01).结论衰老大鼠肾小管间质细胞表型发生明显变化,这种细胞表型的转化可能参与了肾脏的衰老结构的改变与功能的减退.     

大鼠肾脏哺乳动物雷帕霉素靶蛋白随增龄变化的研究

目的 研究大鼠肾脏哺乳动物雷帕霉素靶蛋白(mTOR)随增龄表达的变化规律. 方法 选取3月龄、12月龄及24月龄健康大鼠,分别取大鼠肾组织及原代系膜细胞做衰老相关β-半乳糖苷酶活性(SA-βgal)染色,采用反转录多聚酶链反应(RT-PCR)和Western印迹法(Western blotassay)分别在基因及蛋白质表达水平上检测肾脏组织和细胞中mTOR及磷酸化mTOR(p-mTOR)的表达变化,采用免疫组化和荧光法分别检测mTOR在肾组织及细胞中的表达与定位. 结果 随增龄,大鼠肾脏组织SA-βgal活性增强,且肾小球系膜细胞SA-β-gal染色阳性率逐渐增加,3、12及24月龄阳性率分别为(11.9±3.6)%,(39.0±4.0)%及(86.9±7.4)%,mTOR mRNA表达随增龄逐渐增强,不间月龄比较差异有统计学意义(P<0.05).Western印迹亦显示mTOR及p-mTOR蛋白表达随鼠龄增加逐渐增强(P<0.05).免疫组化结果 显示,mTOR蛋白表达于大鼠肾小球系膜区,其在肾小管一间质也有表达;随增龄,与增龄所致的肾脏病变呈正相关性(与增龄引起小球及小管-间质病变的相关性分别为r=0.838;r=0.742,均为P<0.01);免疫荧光结果 显示,mTOR在大鼠系膜细胞胞浆及胞核内皆有表达,随增龄表达的荧光强度逐渐升高(P<0.05). 结论 mTOR在大鼠肾组织及肾小球系膜细胞中的表达随龄增加,其可能参与了肾脏衰老的进程.     

肾小管上皮细胞转分化中整合素连接激酶表达及其与衰老的相关研究

目的探讨整合素连接激酶(integrin-linked kinase,ILK)在肾小管上皮细胞转分化过程中的作用及其对衰老进程中细胞外基质(extracellular matrix,ECM)积聚增加的影响。方法分离培养3、24月龄 Wistar 雄性大鼠的原代肾小管上皮细胞,分别给予0、5、10、20～40μg/L 不同浓度的转化生长因子β(transforming growth factor β,TGF-β)刺激24h 后,用免疫细胞化学或免疫荧光方法检测细胞α-SMA、ILK、F-actin 表达;Western-blot 法检测两组细胞中纤维连接蛋白和 ILK 的表达水平;体外转录获得大鼠 ILK-c RNA 探针,检测两组细胞经刺激后 ILK mRNA 的变化。结果在0浓度 TGF-β刺激下,肾小管上皮细胞中 ILK 和 F-actin 表达水平24月龄组均比3月龄组高,但两组细胞α-SMA 表达水平均很低,且没有差别;随 TGF-β刺激浓度的增加,ILK、F-actin 和α-SMA 表达水平显著上调,其中 F-actin 与 ILK 表达增多相一致;FN 和 ILK 蛋白表达水平24月龄组分别为0.438±0.024和0.826±0.051,明显高于3月龄组的0.246±0.018和0.673±0.035(P<0.05)。结论随着肾小管上皮细胞转分化程度不断增高,ILK 表达增多,并可能通过调节 F-actin 的重排介导了转分化的过程;随增龄肾小管上皮细胞中 ILK 和 FN 表达增多,且 F-actin 表达随之增多,提示衰老肾脏的肾小管上皮细胞在应激状态下更易于发生转分化。     

过氧化物酶增殖物激活受体γ在不同月龄大鼠肾脏中的表达

目的 观察过氧化物酶增殖物激活受体γ(PPARγ)在大鼠肾脏衰老过程中的表达分布,探讨其可能作用机制.方法 分别以3月龄、12月龄和24月龄SD大鼠为模型,采用Western印迹、免疫组化、原位杂交的方法检测PPARγ蛋白、核酸在不同年龄大鼠肾组织中的表达.结果 PPARγ蛋白在肾组织表达,3月龄大鼠为0.94±0.05,明显高于24月龄大鼠0.78±0.02(t=7.08,P＜0.01),亦高于12月龄大鼠0.87±0.04,但差异无统计学意义(t=2.49,P＞0.05).免疫组化结果显示,PPARγ蛋白在各年龄组大鼠肾小管、集合管上皮细胞中均有分布,主要分布于细胞核内,在老年大鼠肾小球系膜细胞及壁层上皮细胞内也有阳性染色.原位杂交结果显示,PPARγ mRNA的表达分布与免疫组化结果一致.半定量分析显示,在大鼠肾组织的衰老过程中,PPARγ基因表达呈下降趋势.结论 PPARγ作为核转录因子参与了大鼠肾脏衰老过程调控.     

泛素蛋白酶体途径对高糖刺激肾系膜细胞连接蛋白43表达和纤维连接蛋白分泌影响的初步观察

目的 探讨高糖对系膜细胞连接蛋白43(Cx43)表达和纤维连接蛋白(FN)分泌的影响,以及泛素蛋白酶体途径在其中的作用.方法 将培养的大鼠肾小球系膜细胞用高糖作为刺激因子,泛素蛋白酶体特异性抑制剂MG132作为阻断剂,甘露醇作为渗透压对照,观察各组细胞间Cx43的表达并检测细胞上清液中FN的含量.结果 (1)不同浓度的葡萄糖刺激系膜细胞48h后,Cx43表达较正常对照组显著降低,MG132可部分逆转高糖所致的Cx43的低表达(P＜0.05),甘露醇对Cx43表达无影响(P＞0.05).(2)高糖呈浓度依赖性促进系膜细胞 FN的分泌,MG132可部分抑制高糖所致的系膜细胞 FN的分泌(P均＜0.05).结论 高糖呈浓度依赖性抑制系膜细胞Cx43的表达和促进FN的分泌;泛素蛋白酶体途径参与了高糖所致Cx43的低表达和FN分泌.     

胡芦巴多糖A2对大鼠肾小球系膜细胞CTGF表达的影响

目的 探讨胡芦巴多糖A2含药血清对大鼠肾小球系膜细胞细胞外基质(ECM)沉积及结缔组织生长因子(CTGF)表达的影响.方法 制备胡芦巴多糖A2含药血清,体外培养大鼠肾小球系膜细胞,观察胡芦巴多糖A2血清对大鼠肾小球系膜细胞分泌纤维连接蛋白(FN)、胶原(Col)Ⅳ、TGF-β1和CTGF的影响.结果 与高糖培养基组比较,A2组FN、ColⅣ含量明显下降;TGF-β1和CTGFmRNA表达明显下调.结论 胡芦巴多糖A2可通过下调CTGF表达,减少高糖培养的大鼠肾小球系膜细胞FN、ColⅣ的分泌,从而抑制ECM积聚.     

氯沙坦对Thy1肾炎大鼠肾小球系膜细胞CDK2表达的影响

目的 观察氯沙坦对Thy1肾炎大鼠肾小球系膜细胞人细胞周期蛋白依赖性激酶2(CDK2)表达的影响.方法 实验鼠分为Thy1肾炎组、Thy1肾炎+氯沙坦治疗组和正常组.诱导肾脏疾病后,第1、3、5、7天检查病理.用免疫组化方法检测;肾小球内PCNA和CDK2蛋白的表达情况,采用Western印迹分析CDK2的表达情况.结果 对于正常大鼠,其系膜细胞的CDK2表达量很低,但具有系膜细胞增生现象的肾炎大鼠,CDK2表达会有增加趋势.比较而言,用氯沙坦治疗3～7d后,肾小球内的PCNA表达明显低于肾炎组(P＜0.05).结论 CDK2可导致肾小球系膜细胞增生,氯沙坦对系膜细胞CDK2的高表达有明显的抑制作用,进而抑制系膜细胞的增生,表明氯沙坦可以治疗Thy1肾炎大鼠系膜细胞增殖.     

腈水解酶2基因沉默细胞模型的制备

目的为腈水解酶2（NIT2）基因研究奠定基础。方法采用siRNA质粒转染技术制备NIT2基因沉默细胞模型,用筛网方法从大鼠肾脏中提取出肾小球用于培养原代系膜细胞,将NIT2靶序列构建pGU6/GFP/Neo质粒中（siNIT2质粒）,采用JETPRIME脂质体转染法将质粒转染入原代系膜细胞中,48h后荧光显微镜观察转染效率,利用SYBR GREEN 1定量PCR法检测NIT2基因表达,琼脂糖凝胶电泳观察PCR产物。结果荧光显微镜下转染阳性率可达50%,定量PCR结果示siNIT2质粒转染后NIT2 mRNA显著降低,琼脂糖电泳结果示PCR产物无明显杂带。结论 siRNA质粒转染法可抑制原代系膜细胞NIT2基因的表达;为NIT2基因功能研究奠定了基础。     

尿激酶型纤溶酶原激活物对糖尿病大鼠肾脏系膜基质的影响

目的 探讨尿激酶型纤溶酶原激活物（uPA）对糖尿病大鼠肾脏系膜基质表达的影响及机制.方法 8周龄健康雄性SD大鼠（体质量150～200 g）20只尾静脉注射链脲佐菌素,成功建立糖尿病大鼠模型后采用数字表法随机分为糖尿病组（n=10）和uPA组（n=10;尾静脉注射2500 U·kg^-1·d^-1 uPA,共4周）.另以10只正常大鼠为对照组.29d后处死大鼠,心脏取血检测血糖、血肌酐水平.过碘酸六胺银染色测定肾小球平均面积、肾小球平均容积和肾小球系膜区面积.免疫组织化学法检测肾脏尿激酶型纤溶酶原激活物受体（uPAR）、纤溶酶原激活物抑制剂-1（PAI-1）和Ⅳ型胶原表达水平.采用方差分析和q检验进行数据统计.结果 与正常对照组比较,糖尿病组大鼠明显出现尿蛋白[（25.4±4.3）mg/24 h vs（5.5±2.1）mg/24 h,q=4.27,P＜0.01],肾小球体积及系膜基质显著增加,肾小球系膜uPAR、PAI-1、Ⅳ型胶原表达显著增加（q值分别为3.63、3.97、4.21,均P＜0.05）.糖尿病大鼠注射uPA后,尿蛋白明显减少[（12.6±5.4）mg/24 h,q=3.45,P＜0.05],肾小球体积、系膜基质异常有所改善（q值分别为4.34、4.27,均P＜0.01）,肾小球系膜PAI-1、Ⅳ型胶原表达明显减少（q值分别为3.98、4.17,均P＜0.05）.结论注射uPA可明显降低糖尿病大鼠肾小球PAI-1蛋白表达,对uPAR表达的影响不大,提示uPA可能通过与uPAR结合、摄取PAI-1并加速其降解,从而调节肾小球系膜细胞及其基质表达,改善糖尿病系膜基质病变.     

p21~(WAF1/CIP1/SDI1)在大鼠肾脏组织的增龄性变化及意义

目的 研究p21野生型p53活化片段1/细胞周期蛋白依赖性激酶影响蛋白1/衰老细胞衍生抑制剂1(p21WAF1/CIP1/SDI1)在大鼠肾脏中随年龄增长的表达变化规律. 方法 取3月龄、12月龄及24月龄健康雄性Wistar大鼠肾组织进行衰老相关β-半乳糖苷酶(SA-β-gal)活性染色,TUNEL法检测细胞凋亡,采用逆转录多聚酶链反应(RT-PCR)和Western印迹法(Western blot assay)分别在基因及蛋白质表达水平上检测肾脏组织中p21WAF1/CIP1/SDI1的表达变化,并用免疫组化法检测p21WAF1/CIP1/SDI1在肾脏组织中的表达与定位. 结果 大鼠肾脏组织SA-β-gal活性随年龄增长逐渐增强,凋亡细胞也随年龄增长逐渐增加(P＜0.05);p21WAF1/CIP1/SDI1 mRNA表达随年龄增长逐渐增强,不同月龄比较差异有统计学意义(P＜0.05).Western印迹亦显示p21WAF1/CIP1/SDI1蛋白表达随鼠龄增加逐渐增强(P＜0.05).免疫组化结果显示,p21WAF1/CIP1/SDI1蛋白表达于大鼠肾小球足细胞,其在肾小管与间质细胞中也有表达,且随年龄增长表达增加(P＜0.05). 结论 p21WAF1/CIP1/SDI1在大鼠肾脏组织中的表达随年龄增加而增强,可作为肾脏组织中重要的衰老指标.     

整合素连接激酶在衰老鼠肾间质损害中的表达及意义

目的探讨整合素连接激酶(ILK)在衰老鼠肾间质损害中的表达和意义。方法将3月龄、26月龄Wistar大鼠制成单侧输尿管梗阻(UUO)模型,用免疫荧光、Westernblot、RT-PCR等方法动态观察不同鼠龄间ILK、纤维连接蛋白(Fn)的mRNA和蛋白在UUO术前及术后3、7、14d表达的变化。结果随UUO术后时间的延长,各月龄鼠肾间质相对面积及肾小管间质纤维化面积明显增加(P<0·01),Fn、ILK的mRNA和蛋白表达也增加(P<0·01);26月龄与3月龄UUO大鼠ILKmRNA半定量值在术后3d为0·98±0·06、0·72±0·06,术后14d为1·49±0·05、1·03±0·04;ILK蛋白半定量值在术后3d为0·57±0·04、0·52±0·03,术后14d为0·76±0·04、0·63±0·03。随UUO术后时间的延长,ILK的mRNA和蛋白表达水平与肾间质相对面积的改变呈正相关(r分别为0·71、0·80,P值均小于0·05)。结论ILK的表达随鼠龄的增加及UUO术后时间的延长呈进行性增加,其高表达可能是促进肾脏纤维化和肾脏衰老的原因之一。     

整合素连接激酶在重组结缔组织生长因子诱导大鼠肝星状细胞表型转化中的作用

目的研究整合素连接激酶(ILK)在重组结缔组织生长因子(rCTGF)诱导大鼠原代肝星状细胞(HSC)表型转化中的作用。方法应用胶原酶原位灌注+密度梯度离心法分离SD大鼠原代HSC,细胞贴壁培养24 h后以rCTGF处理,24 h后转染ILK小干扰RNA(siRNA)或对照siRNA,设rCTGF对照及空白对照。应用RT-PCR及Western Blot检测转染siRNA 24、48及72 h时HSCα平滑肌肌动蛋白(αSMA)、ILK及I型胶原基因表达水平变化。计量资料采用t检验。结果与空白对照相比,rCTGF处理可显著上调大鼠HSCαSMA、ILK蛋白及I型胶原mRNA表达。转染ILK siRNA可特异性抑制rCTGF诱导的ILK表达上调,与rCTGF对照相比,转染ILK siRNA 24、48及72 h时,HSC ILK蛋白表达分别下调72%±6%(t=21.39,P0.01)、87%±9%(t=68.25,P0.01)及47%±3%(t=18.25,P=0.003);αSMA蛋白及I型胶原mRNA表达分别下调5%±1%(t=2.52,P0.05)及6%±3%(t=1.63,P0.05)、31%±7%(t=34.77,P0.01)及20±5%(t=6.71,P0.05)和67%±8%(t=58.82,P0.01)及43%±6%(t=15.21,P0.01);转染对照siRNA时,HSC ILK、αSMA及I型胶原mRNA表达在相同时点无显著变化。结论 ILK可能部分介导了rCTGF诱导的大鼠HSC表型转化。     

Integrin-linked kinase induces both senescence-associated alterations and extracellular fibronectin assembly in aging cardiac fibroblasts

Integrin-linked kinase (ILK) is an integrin-binding cytoplasmic protein that is involved in regulating numerous cellular processes and extracellular matrix accumulation. We reported that ILK may be involved in cellular senescence, but whether ILK is the cause of senescence or an accompanying phenomenon still remains to be explored. Here, RNA interference and gene transfer techniques were used to knock down and overexpress ILK in 3-month-old and 28-month-old rat primary cardiac fibroblasts. The results show that, in younger cells, ILK overexpression induces larger cell shapes, lower proliferation capacity, and higher levels of enzymatic beta-galactosidase activity, and increases basal p53 and p21 protein levels, whereas knock-down of ILK prevents phenotypic changes typical of senescence in aging cells. In addition, ILK could induce the cytoskeleton proteins to organize into dense, thick bundles of filaments, which contribute to cellular enlargement and extracellular fibronectin assembly. The results indicate that ILK can accelerate the process of cellular senescence.     

Expression and significance of integrin-linked kinase in cultured cells, normal tissue, and diseased tissue of aging rat kidneys

Integrin-linked kinase (ILK) is an integrin-binding cytoplasmic protein that has been implicated in regulating numerous cellular processes and fibronectin (Fn) deposition through mediated integrin, but the expression and significance of ILK in the aging kidney have not yet been reported. We report here that mRNA and protein expression of ILK increased in primary cultured mesangial and tubular epithelial cells, and normal and unilateral ureteral obstructed kidney tissues in 28-month-old rats but not in 3-month-old rats, moreover, accompanied by the over-expression of Fn and integrin-beta1 in the aging kidney, by means of Northern blot, Western blot, and immunofluorescent double-staining immunohistochemistry. In addition, in the primary cultured kidney cells, ILK expression was positively correlated with senescence-associated beta-gal positive staining and negatively correlated with cellular proliferation. The results suggest that ILK may be involved in the fibrotic or senescent process in the aging kidney.     

Integrin-linked kinase overexpression promotes epithelial-mesenchymal transition via nuclear factor-κB signaling in colorectal cancer cells

AIM: To investigate the effect of integrin-linked kinase(ILK) on proliferation, metastasis, and invasion of the colorectal cancer cell line SW480. METHODS: In this study, the colorectal cancer cell line SW480 was stably transfected with ILK plasmids, and small interfering RNA(si RNA) was used to knockdown expression of nuclear factor(NF)-κB/p65. Methylthiazole tetrazolium(MTT) assay was performed to measure proliferation, and the wound healing migration assay and matrigel invasion assay were used to test the metastasis and invasion ability of SW480 cells. To explore the epithelial-mesenchymal transition(EMT) process, embryonic development, and the invasion and metastasis of tumors, the protein level of E-cadherin, vimentin, snail, and slug was detected by western blot. Immunofluorescence was also used to detect E-cadherin expression. Western blot was used to determine the level of phosphorylated-inhibitor of kappa B(IκB)a, inhibitor of gamma B(IγB)a, and nuclear factor kappa B(NF-κB) expressions and toexplore the ILK signaling pathway. RESULTS: Western blot results revealed that ILK expression significantly increased when ILK was overexpressed in SW480 cells(P 0.05). Proliferation, metastasis, and invasion ability were improved in the vector-ILK group compared to the vector group(P 0.05). Immunofluorescence results revealed that E-cadherin fluorescence intensity decreased after ILK was overexpressed(P 0.05). Western blot results revealed that the protein expression of E-cadherin was reduced, while vimentin, snail, and slug were upregulated when ILK was overexpressed in SW480 cells(P 0.05). In order to determine the role of the NF-κB signaling pathway in ILK overexpression promoted EMT occurrence, we overexpressed ILK in SW480 cells and found that levels of NF-κB/p65 and cytoplasmic phosphorylated-IκBa were increased and that cytoplasmic IкBa levels were decreased compared to the control group(P 0.05). Furthermore, NF-κB/p65 knockout revealed that E-cadherin was increased in the overexpressed ILK group. CONCLUSION: ILK overexpression improved the proliferation, metastasis, and invasion ability of SW480 cells, and this effect may be mediated by the NF-κB signaling pathway.     

小干扰RNA对人内皮细胞株类表皮生长因子域7基因表达抑制作用的实验研究

目的 研究小干扰RNA（siRNA）对类表皮生长因子域7（egfl7）基因表达的抑制作用。方法 利用Ambion公司设计合成的以egfl7为靶标的siRNA,通过脂质体将siRNA转入人脐静脉内皮细胞株,以未转染siRNA细胞和转染无关siRNA细胞为对照,利用MTS[3-（4,5-dimethyhhiaz-2-y1）-5（3-carboxymethoxyphenyl）-2-（4-sulfopheny）-2H-tetrazolium,innersalt]法检测siRNA对细胞存活率的影响,同时检测乳酸脱氢酶和三磷酸腺苷,观察siRNA对细胞生长的影响,RT-PCR法检测egfl7mRNA水平的改变,Westernblot检测egfl7蛋白表达的变化。结果 siRNA各组与对照组细胞存活率差异均有统计学意义（P〈0．05）,乳酸脱氢酶及三磷酸腺苷释放量差异也存在统计学意义（P〈0．01）。转染24h后,siRNA组egfl7mRNA与对照组相比差异有统计学意义（P〈0．01）,同时egfl7蛋白表达也被明显抑制（P〈0．01）,其中siRNA1的抑制效率最高。结论 体外转录合成的siRNA可抑制人脐静脉内皮细胞egfl7基因的表达。     

FoxO1基因沉默对胰岛素抵抗细胞葡萄糖消耗的影响及其机制

目的 探讨抑制叉头状转录因子O1(FoxO1)基因表达对胰岛素抵抗HepG-2细胞葡萄糖消耗的影响及可能机制.方法 构建针对转录因子FoxO1 mRNA特异性的携带红色荧光标记的siRNA载体,并测序鉴定.高浓度(10-6mol/L)胰岛素诱导24 h建立胰岛素抵抗细胞模型.实验共分4组:A组为普通培养基培养的细胞组;B组为未处理胰岛索抵抗细胞组;C组为转染FOxO1 siRNA载体的胰岛素抵抗细胞组;D组为以转染试剂为对照的胰岛素抵抗细胞组.转染后荧光显微镜下观察红色荧光的表达;葡萄糖氧化酶法检测各组细胞葡萄糖的消耗;RT-PCR技术检测FOxO1 mRNA表达;Western印迹和免疫沉淀技术检测胰岛素受体底物2(IRS-2)蛋白表达及酪氨酸磷酸化水平.结果 经测序,成功构建了FoxO1 siRNA 载体.在转染后48 h,细胞内红色荧光表达最强.此时,与A组比较,B组葡萄糖消耗量降低(P<0.01),FoxO1 mRNA表达增强(P<0.05),IRS-2蛋白表达无显著性差别(P>0.05),但其酪氨酸磷酸化明显降低(P0.05).结论 抑制FoxO1基因在胰岛素抵抗细胞中的高表达,可改善胰岛素敏感性,其机制可能是通过反馈调节IRS-2蛋白酪氨酸磷酸化,增强胰岛素信号转导.     

FoxO1基因沉默对胰岛素抵抗细胞葡萄糖消耗的影响及其机制

目的 探讨抑制叉头状转录因子O1(FoxO1)基因表达对胰岛素抵抗HepG-2细胞葡萄糖消耗的影响及可能机制.方法 构建针对转录因子FoxO1 mRNA特异性的携带红色荧光标记的siRNA载体,并测序鉴定.高浓度(10-6mol/L)胰岛素诱导24 h建立胰岛素抵抗细胞模型.实验共分4组:A组为普通培养基培养的细胞组;B组为未处理胰岛索抵抗细胞组;C组为转染FOxO1 siRNA载体的胰岛素抵抗细胞组;D组为以转染试剂为对照的胰岛素抵抗细胞组.转染后荧光显微镜下观察红色荧光的表达;葡萄糖氧化酶法检测各组细胞葡萄糖的消耗;RT-PCR技术检测FOxO1 mRNA表达;Western印迹和免疫沉淀技术检测胰岛素受体底物2(IRS-2)蛋白表达及酪氨酸磷酸化水平.结果 经测序,成功构建了FoxO1 siRNA 载体.在转染后48 h,细胞内红色荧光表达最强.此时,与A组比较,B组葡萄糖消耗量降低(P<0.01),FoxO1 mRNA表达增强(P<0.05),IRS-2蛋白表达无显著性差别(P>0.05),但其酪氨酸磷酸化明显降低(P0.05).结论 抑制FoxO1基因在胰岛素抵抗细胞中的高表达,可改善胰岛素敏感性,其机制可能是通过反馈调节IRS-2蛋白酪氨酸磷酸化,增强胰岛素信号转导.     

Berberine attenuates lipopolysaccharide-induced extracelluar matrix accumulation and inflammation in rat mesangial cells: Involvement of NF-κB signaling pathway

Background

Our previous studies demonstrated that berberine could improve the renal function in rats and mice with diabetic nephropathy (DN) and inhibit extracellular matrix (ECM) component, fibronectin (FN) expression in rat mesangial cells (MCs) cultured under high glucose. However, the molecular mechanisms have not been fully elucidated.

Objective

To explore the potential mechanisms of berberine in the treatment of DN, we investigated the effects of berberine on lipopolysaccharide (LPS)-induced nuclear factor-kappa B (NF-κB) activation and its downstream inflammatory mediators, such as intercellular adhesion molecule-1 (ICAM-1), transforming growth factor-beta 1 (TGF-β1), inducible nitric oxide synthase (iNOS) and fibronectin (FN) protein expression in rat MCs.

Method

Cell proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). The activation of NF-κB was detected by Western blot and confocal microscopy. The protein levels of ICAM-1, TGF-β1, iNOS and FN in rat MCs were detected by Western blot.

Results

Our results revealed that berberine significantly suppressed LPS-induced cell proliferation and inhibited LPS-induced NF-κB nuclear translocation in MCs, as well as protein expression of ICAM-1, TGF-β1, iNOS and FN.

Conclusion

Berberine significantly repressed LPS-induced cell proliferation and FN expression in rat MCs through inhibiting the activation of NF-κB signaling pathway and protein expression of its downstream inflammatory mediators. The ameliorative effects of berberine on DN might be associated with this inhibition effect on NF-κB signaling pathway which was independent of its hypoglycemic effect.     

Role of complement 3a in the growth of mesangial cells from stroke-prone spontaneously hypertensive rats

Vascular smooth muscle cells (VSMCs) derived from spontaneously hypertensive rats (SHR) show exaggerated growth with a synthetic phenotype and angiotensin II (Ang II) production associated with increased production of complement (C3). We hypothesized that C3 is involved in the growth of mesangial cells (MCs) from hypertensive rats. We examined the effects of a C3a receptor inhibitor on proliferation, phenotype and Ang II generation in MCs from stroke prone-spontaneously hypertensive rats (SHR)-SP, SHR and Wistar-Kyoto (WKY) rats. Expression of C3 and C3a receptor were evaluated by immunohistochemical staining of the renal cortex. We examined the effects of the C3a inhibitor, SB290157, on proliferation, the expression of phenotype-marker mRNAs and Ang II production in cells from SHR-SP, SHR and WKY rats. Immunostaining of C3 was stronger in SHR and SHRSP glomeruli. MCs from SHR-SP and SHR abundantly express pre-pro C3 mRNA. SB290157 significantly inhibited basal DNA synthesis and proliferation of MCs from SHR-SP and SHR. Expression of osteopontin mRNA in MCs from SHR-SP and SHR was decreased with SB290157 treatment, whereas MC basal expression of α-SMA mRNA was decreased. SB290157 significantly decreased the production of Ang II in MCs from SHR-SP and SHR. Endogenous C3a promotes exaggerated growth with a synthetic phenotype and the production of Ang II in MCs from SHR-SP and SHR. The C3 and C3a receptor system may primarily be involved in the pathogenesis of renal remodeling in hypertensive rats.