Lipophilization of Somatostatin Analog RC-160 Improves Its Bioactivity and Stability

Purpose. Acromegaly is a symptomatically disabling condition, resulting from a growth hormone (GH) secreting pituitary tumor. The somatostatin analog RC-160 is known to potently inhibit hypersecretion of GH, from pituitary adenomas. However, the therapeutic potential of RC-160, is limited by its short serum half life. To overcome this limitation, fatty acids with carbon chain lengths ranging from 4 to 18 were conjugated to RC-160. Methods. The GH-inhibitory activity of these lipopeptides, as well as their binding profile to somatostatin receptors, on the rat pituitary adenoma cell line GH3 was studied in vitro. The relative stability of lipophilized RC-160 towards degradation by crude papaya protease was also determined. Results. The long chain lipopeptides, like myristoyl-RC-160 (carbon chain length = 14) were found to exhibit greater receptor affinity and GH-inhibitory activity, as compared to their counterparts of lower chain lengths. However, the receptor affinity and GH-inhibitory activity of stearoyl-RC-160 (carbon chain length = 18), was found to lower than RC-160 and its lipophilized derivatives. Unlike RC-160, the myristoylated derivative was found to have significantly greater resistance to protease and serum degradation (p < 0.01). Conclusions. Lipophilization of RC-160 with long chain fatty acids improves its stability and GH-inhibitory activity. The activity of lipophilized RC-160 seems to increase with increasing hydrophobicity of the lipopeptide, and reaches a maxima at myristoyl-RC-160 for GH3. Hence, optimizing the hydrophobicity should be an important consideration governing the design and synthesis of bioactive lipopeptides.     

N-terminal acylation of somatostatin analog with long chain fatty acids enhances its stability and anti-proliferative activity in human breast adenocarcinoma cells

The anti-proliferative activity of the somatostatin analog RC-160 is limited by its short serum half life. To circumvent this limitation, fatty acids of chain lengths ranging from 4 to 18 were individually conjugated to the N-terminal residue of RC-160. The lipophilized derivatives of RC-160 were synthesized, purified and characterized. The anti-proliferative activity of lipophilized-RC-160 on the human breast carcinoma cell line MCF-7, was evaluated in vitro. The long chain lipopeptides like pamitoyl-RC-160 exhibited significantly higher anti-proliferative activity on MCF-7 cells (p<0.001), relative to RC-160. The affinity of RC-160 towards somatostatin receptors remained unaltered by pamitoylation. However, the observed increase in bioactivity was manifested within an optimum range of chain length of the lipoppetide. Increasing the peptide hydrophobicity beyond this range reduced the bioactivity of lipophilized-RC-160. Accordingly, stearoyl-RC-160, manifested lower anti-neoplastic activity and receptor affinity relative to pamitoyl-RC-160 and RC-160 itself. The signaling pathways underlying the antineoplastic activity of these lipopeptides were found to be similar to RC-160. Pamitoyl-RC-160 displayed enhanced inhibition of protein tyrosine kinase activity and intracellular cAMP levels in MCF-7 cells, relative to butanoyl-RC-160 or RC-160 itself. Pamitoyl-RC-160 also displayed greater resistance towards trypsin and serum degradation than RC-160. Lipophilization of RC-160 with long chain fatty acids like pamitic acid improves its stability and anti-proliferative activity, thereby improving the scope of enhancing its therapeutic index. However, the optimization of peptide hydrophobicity seems to be a crucial factor governing the efficacy of bioactive lipopeptides.     

2种海参胶原蛋白多肽对血管内皮细胞保护作用的比较研究

目的 观察革皮氏海参和北极刺参胶原蛋白多肽对氧化型低密度脂蛋白(ox-LDL)损伤的血管内皮细胞的保护作用,探讨其保护内皮细胞的作用机制。方法 采用ox-LDL处理血管内皮细胞(ECV304)建立氧化应激损伤模型,以MTT法测定ECV304的增殖活性,硫代巴比妥酸法测定细胞内的丙二醛(MDA)含量,比色法测定一氧化氮合酶(NOS)活力和一氧化氮(NO)释放量,Hoechst33258染色法检测细胞的凋亡,Western blotting法检测caspase-3蛋白的表达。结果 经2种海参胶原蛋白多肽预处理后,ECV304细胞的增殖率显著升高 (P<0.05,P<0.01),细胞凋亡比率和MDA含量显著降低(P<0.05,P<0.01),细胞NOS活力和NO释放量均显著提高 (P<0.05,P<0.01),凋亡蛋白caspase-3的表达量显著降低。结论 2种海参胶原蛋白多肽均能有效保护脂质过氧化物损伤的血管内皮细胞,其中北极刺参胶原蛋白多肽在抑制细胞凋亡和提高NOS活性方面效果更突出,可能与其氨基酸组成有关。     

桂哌齐特拮抗氧化低密度脂蛋白对人脐静脉内皮细胞的损伤

目的研究桂哌齐特对氧化低密度脂蛋白(ox-LDL)损伤人脐静脉内皮细胞系ECV304的保护作用。方法传代培养ECV304细胞,随机分为空白对照组、模型组、桂哌齐特(200mg·L~(-1)和400mg·L~(-1))组,与ox-LDL共同孵育24h制模,观察培养上清液中一氧化氮(NO)与丙二醛(MDA)含量的变化,测定Fura-2/AM负载后的内皮细胞的游离静息钙浓度([Ca~(2+)]_i)。结果 ox-LDL诱导的模型组上清液中NO的浓度明显降低,MDA含量显著升高(均P<0.01)。桂哌齐特组NO浓度增加(P<0.01),MDA含量降低均(P<0.05)。与空白对照组相比,模型组的[Ca~(2+)]_i显著升高,桂哌齐特组能降低损伤导致的[Ca~(2+)]_i升高(均P<0.01)。结论桂哌齐特能拮抗ox-LDL对人脐静脉内皮细胞的损伤作用。     

哇巴因对血管内皮细胞ECV304细胞凋亡及胞内游离钙离子和活性氧浓度的影响

目的研究哇巴因(毒毛花苷G)对人脐静脉血管内皮细胞ECV304凋亡的诱导作用,并探讨其可能的作用机制。方法哇巴因0.01,0.05,0.1,0.5,1和10μmol·L-1与ECV304细胞作用24,48和72h,MTT法检测细胞存活率,Hoechst33342/碘化丙锭双荧光染色法和流式细胞仪检测细胞凋亡百分率,激光共聚焦显微镜观察细胞内游离Ca2+浓度([Ca2+]i)和活性氧(ROS)浓度,逆转录PCR和Western印迹法检测胱天蛋白酶3mRNA和蛋白表达。结果哇巴因在0.01～10μmol·L-1浓度范围内与ECV304细胞分别作用24,48和72h,对细胞存活的抑制率明显增加,且呈浓度和时间依赖性,24,48和72h浓度-效应相关系数分别为0.984,0.994和0.997(P<0.05);哇巴因作用24,48和72h的IC50值分别为0.624,0.184和0.041μmol·L-1,时间-效应相关系数为0.974(P<0.05)。哇巴因0.1μmol·L-1与ECV304细胞作用24h,细胞凋亡百分率由正常对照组的(4.2±0.5)%升高到(26.0±3.2)%,作用48h,细胞凋亡率由(4.7±0.5)%升高到(36.5±5.3)%,差异有统计学意义(n=3,P<0.01);同时细胞出现染色质凝集。哇巴因0.01,0.1和0.5μmol·L-1分别与ECV304细胞作用12,24和36h,[Ca2+]i和ROS浓度呈浓度和时间依赖性增加,在哇巴因0.5μmol·L-1时[Ca2+]i和ROS浓度的时间-效应相关系数分别为0.912和0.924,作用36h时[Ca2+]i和ROS浓度的浓度-效应相关系数分别为0.889和0.907(P<0.05)。逆转录PCR和Western印迹法分析显示,哇巴因0.1和0.5μmol·L-1作用ECV304细胞24h后,胱天蛋白酶3mRNA表达增加,差异有统计学意义(P<0.05);哇巴因0.01,0.1和0.5μmol·L-1作用ECV304细胞24h,胱天蛋白酶3蛋白表达明显增加,差异有统计学意义(P<0.05)。结论哇巴因可诱导人脐静脉血管内皮细胞ECV304凋亡,其机制可能与增加[Ca2+]i和ROS浓度及胱天蛋白酶3表达有关。     

Effect of somatostatin analogs on gastric acid secretion in dogs and rats

The effects of several superactive analogs of somatostatin on gastric acid response to various exogenous and endogenous stimulants were investigated in conscious dogs and rats with gastric fistulae (GF). The inhibition was compared to that induced by somatostatin-14 (S-S-14) at two dose levels. Several octapeptide analogs of somatostatin including (RC-160) and (RC-121), which were superactive in tests on suppression of GH levels, were 4-5 times more potent than S-S-14 in inhibiting desglugastrin-stimulated gastric acid secretion in GF dogs. The analog RC-160 also reduced the rise in serum gastrin levels and gastric acid secretion induced by sham feeding (SF) in dogs with gastric and esophageal fistulae (EF), but did not decrease food consumption. Gastric acid secretion induced by histamine (80μg/kg/h) in dogs was not affected by 1-5μg/kg/h of analog RC-121 or by 5μg/kg/h of S-S-14. Analogs RC-160, RC-121, and RC-98-I and others also powerfully inhibited desglugastrin-induced gastric acid secretion in GF rats. Hexapeptide cyclo(-Pro-Phe-D-Trp-Lys-Thr-Phe) was only about half as potent as S-S-14 in dogs but its activity was higher in rats. The results indicate that octapeptide analogs which are superactive in GH-inhibition tests are also more potent than S-S-14 in suppressing gastric acid secretion. These findings may be of clinical value.     

Lipophilized epigallocatechin (EGC) and its derivatives: Inhibition of oxidation of β-carotene–linoleate oil-in-water emulsion and DNA strand scission

Tea epigallocatechin (EGC) was acylated with selected fatty acids, namely propionic acid [C3:0], caprylic acid [C8:0], lauric acid [C12:0], stearic acid [C18:0] and docosahexaenoic acid (DHA; C22:6 n-3). Antioxidant activity of EGC and its lipophilized derivatives were examined in various food (β-carotene–linoleate oil-in-water emulsion and bulk oil) and biological (supercoiled DNA and LDL) systems in vitro in order to evaluate the effect of increased lipophilicity on their antioxidant capacity. Lipophilized EGC derivatives were more effective in β-carotene–linoleate oil-in-water emulsion and bulk oil than their parent EGC molecule. Meanwhile, EGC and its derivatives showed more than 60% inhibition against DNA strand scission induced by hydroxyl or peroxyl radical. Moreover, lipophilization of EGC had a negative effect on the inhibition of human LDL cholesterol peroxidation. Overall, this study revealed that EGC and its lipophilized derivatives could potentially be used as health promoting and disease preventing compounds.     

Protective effect of quercetin on the homocysteine-injured human umbilical vein vascular endothelial cell line (ECV304)

Homocysteine is responsible for the occurrence of many cardiovascular diseases for instance by injuring the vascular endothelial cells. Quercetin has many beneficial effects on the cardiovascular system, but it is unknown whether it provides protection against homocysteine-injured vascular endothelial cells. The aim of the present study was to investigate the protective effect and mechanism of quercetin on the homocysteine-injured human umbilical vein vascular endothelial cell line (ECV304) (i.e. morphology, viability and nuclear factor kappa B (NF-kappaB) expression of ECV304 injured with 1.0 mM homocysteine) by determination of lipid peroxidant and endothelium-derived factors in the cultural medium of homocysteine-injured ECV304. Quercetin at 6.25, 12.5, 25, 50 and 100 microM attenuated the morphological changes and increased viability of homocysteine-injured ECV304 in a dose-dependent manner (P < 0.05 or P < 0.01 versus the homocysteine-injured group). At the same time, quercetin at 12.5, 25 and 50 microM decreased malondialdehyde level, endothelin release and NF-kappaB expression, and increased superoxide dismutase activity, nitric oxide and 6-keto-prostaglandin F1alpha releases in homocysteine-injured ECV304 (P < 0.05 or P < 0.01 versus the homocysteine-injured group). These results suggest that quercetin has a protective effect on homocysteine-injured vascular endothelial cells by antioxidant and anti-inflammatory mechanisms.     

降糖复方含药血清对氧化损伤内皮细胞的保护作用

目的：研究降糖复方含药血清对H2O2诱导的血管内皮细胞氧化损伤的保护作用。方法：采用H2O2诱导人脐静脉血管内皮细胞（ECV304）氧化损伤模型,观察细胞形态学变化并测定细胞活力、丙二醛（MDA）、超氧化物歧化酶（SOD）的含量,NO含量以及内皮素（ET-1）含量。结果：降糖复方含药血清可明显改善氧化损伤的ECV304细胞形态学变化,提高细胞存活率,降低MDA含量、提高SOD活力、增加NO释放、减少ET-1释放。结论：降糖复方含药血清能对抗H2O2对血管内皮细胞的氧化损伤,起到保护血管内皮细胞的作用。     

Selective uptake of the somatostatin analog RC-160 across the blood-brain tumor barrier of mice with KHT sarcomas.

The development of somatostatin analogs with anti-tumor effects has raised hopes for their use in various cancers and tumors of the central nervous system. However, for many therapeutic agents, access to normal brain is retarded by the blood-brain barrier (BBB) and to tumor tissues by a blood-brain tumor barrier (BBTB). We examined the ability of RC-160, a somatostatin analog with known anti-tumor activity, to cross the normal BBB and the BBTB in mice with brain sarcomas. In comparison with the normal BBB, the BBTB was about 10 times more permeable to the vascular marker albumin (radioactively labeled with 99mTc), but the BBTB still represents a substantial barrier. By contrast, the entry rate of RC-160, radioactively labeled with 125I, into brain sarcomas was 60 times higher than into normal brain tissue; more than 1% of the RC-160 injected i.v. was taken up by each gram of brain tumor. These results show that a brain tumor can selectively accumulate the potentially therapeutic agent RC-160.     

鲁斯可皂苷元对HL-60与EC V304细胞黏附的影响

目的考察麦冬中主要皂苷元鲁斯可皂苷元(Rusco-gen in)抑制细胞黏附的作用,为深入研究其抗炎作用机制提供依据。方法采用MTT比色法检测Ruscogen in对人原髓性白血病细胞株HL-60细胞与正常或肿瘤坏死因子-α(TNF-α)活化的人脐静脉内皮细胞株ECV304细胞黏附的影响及其对ECV304与HL-60细胞增殖的影响。结果Ruscogen in 0.1,1.0μmol.L-1预处理ECV304细胞后,均抑制TNF-α诱导的ECV304细胞与HL-60细胞黏附的增加,Ruscogen in 0.001,0.01,0.1μmol.L-1预处理HL-60后,亦抑制TNF-α诱导的ECV304细胞与HL-60细胞黏附的增加;同时Ruscogen in在实验浓度范围内不影响ECV304细胞与HL-60细胞的增殖及二者之间的正常黏附。结论Ruscoge-n in可通过抑制HL-60细胞与活化的ECV304细胞之间的黏附作用,发挥抗炎活性。     

Alterations of furosemide binding to serum albumin induced by increased level of fatty acid

Localization of high and low affinity binding sites of furosemide in human serum albumin (HSA) as well as the influence of myristic acid on the drug binding to the albumin using fluorescence quenching method was investigated. Two independent classes of binding site in subdomain IIA of HSA structure were found. Alteration of protein affinity towards the drug and the participation of tryptophanyl and tyrosil residues in drug–albumin interaction for the determined binding sites were studied. It was concluded that association of myristic acid in its low affinity binding sites which corresponds to elevated fatty acid level in vivo, significantly decreases albumin affinity towards furosemide.     

丹酚酸B镁盐抑制低氧诱导内皮细胞钙内流和一氧化氮释放

AIM: To investigate the inhibitory effect of magnesium lithospermate B (MLB) on hypoxia-induced elevation of intracellular calcium concentration ([Ca2+]i) and nitric oxide (NO) release in endothelial cells. METHODS: The cultured human umbilical vein endothelial cells (ECV304) were cultured for 30 min under 95 % N(2) and 5 % CO2. Cell injury was evaluated by dye exclusion test and lactate dehydrogenase (LDH) assay. [Ca2+]i was determined by Fura 2-AM. NO content was examined by the NO assay kit. Endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) mRNA expressions were measured by semi-quantitative RT-PCR. RESULTS: Cell viability was decreased from (93.0 +/- 2.6) % in normoxia to (85.5 +/- 2.1) % in hypoxia (P < 0.01), and LDH release was increased from (41 +/- 28) U/L in normoxia to (141+/-68) U/L in hypoxia (P < 0.01) in ECV304 cultured under calcium conditions. MLB 5 and 10 mg/L improved cell viability and inhibited LDH leakage in ECV304. In addition, hypoxia increased [Ca2+]i, NO release, and eNOS and iNOS mRNA expressions in ECV304 (P < 0.01). These increases could be inhibited by MLB 5 and 10 mg/L (P < 0.01), but they were unaffected by hypoxia under calcium-free conditions. CONCLUSION: MLB attenuates hypoxia-induced cell injury and inhibits hypoxia-induced increases of [Ca2+]i, NO release, and eNOS and iNOS mRNA expressions in ECV304 in Krebs'solution containing calcium. The decreases of NO production and eNOS mRNA expression are possibly associated with inhibition of extracellular calcium influx in MLB-treated ECV304     

白藜芦醇和紫檀芪体外抗肿瘤转移作用

目的比较白藜芦醇和紫檀芪体外抗肿瘤转移作用。方法白藜芦醇和紫檀芪5～50μmol·L-1分别与小鼠黑色素瘤细胞B16F1和内皮细胞ECV304作用48 h,再分别用磺基罗丹明B染色法测定细胞增殖率。白藜芦醇和紫檀芪10μmol·L-1与细胞作用48 h,用划痕实验评价B16F1和ECV304细胞体外迁移能力,用明胶酶电泳和ELISA测定B16F1细胞分泌基质金属蛋白酶2(MMP-2)的活性和含量。用重建基底膜法观察白藜芦醇和紫檀芪10μmol·L-1作用24 h对ECV304细胞拟管腔形成的抑制作用。结果白藜芦醇和紫檀芪作用48 h均能显著抑制B16F1和ECV304细胞增殖,抑制B16F1细胞增殖的IC50分别为119.7μmol·L-1和37.3μmol·L-1,抑制ECV304细胞增殖的IC50分别为72.2μmol·L-1和37.2μmol·L-1。白藜芦醇和紫檀芪10μmol·L-1作用48 h,B16F1细胞愈合率分别为58.0%和36.8%,ECV304细胞愈合率分别为61.8%和28.9%,明显低于正常对照组的67.7%和88.4%(P<0.01),而且紫檀芪组明显低于白藜芦醇组(P<0.01)。与正常对照组相比,白藜芦醇和紫檀芪10μmo·L-1作用48 h使B16F1细胞MMP-2蛋白表达分别降低7.4%和13.9%(P<0.01),MMP-2活性分别降低19.3%和78.9%(P<0.01)。白藜芦醇和紫檀芪作用24 h均可使ECV304细胞管腔样结构破坏,且紫檀芪的作用较白藜芦醇更加明显。结论白藜芦醇和紫檀芪均具有抑制B16F1和ECV304细胞增殖和转移的作用,并能抑制ECV304细胞拟管腔形成;浓度为10μmol·L-1时紫檀芪的抑制作用强于白藜芦醇。     

溶血磷脂酰胆碱对ECV304细胞中血管内皮生长因子表达的影响(英文)

目的:研究溶血磷脂酰胆碱(LPC)对内皮细胞(EC)中血管内皮生长因子(VEGF)表达的影响。方法:在人脐静脉内皮细胞株ECV04培养基中加入不同浓度的LPC,培养不同时间,用基础酶联免疫吸附实验(ELISA)检测各组EC条件培养基中VEGF蛋白含量;用免疫组织化学法检测EC中VEGF蛋白及其受体的表达;用原位杂交检测VEGF信使核糖核酸(VEGF mRNA)的表达。结果:培养的ECV304能表达VEGF受体,在胞浆内呈棕色颗粒,当LPC刺激后,阳性增强。原位杂交结果显示,培养的ECV304中未见VEGF mRNA的表达,当LPC刺激后可见VEGF mRNA的高表达,在胞浆内呈棕色颗粒。ELISA结果显示LPC可使ECV304条件培养基中VEGF蛋白含量明显增加,且具有时间和剂量依赖性。结论:LPC能诱导ECV304表达高水平的VEGF。 (责任编辑 吕静)     

丹酚酸B镁盐对缺氧复氧内皮细胞内钙和一氧化氮的影响

目的:研究丹酚酸B镁盐对缺氧复氧引起的内皮细胞内钙升高和一氧化氮释放增加的影响.方法:培养的人脐静脉内皮细胞(ECV304)暴露在95％ N_2 5％CO_2条件下缺氧30分钟,后在含5％CO_2的空气中复氧30分钟.内皮细胞的损伤用染料排除实验、SOD的活性和MDA的生成来评价.胞内游离钙浓度用钙荧光探针Fura 2-AM测定.一氧化氮含量用一氧化氮试剂盒测定.内皮型一氧化氮合酶(eNOS)mRNA和诱导型一氧化氮合酶(iNOS)mRNA的表达用半定量逆转录聚合酶链式反应(RT-PCR)检测.结果:缺氧复氧引起内皮细胞的活力由正常条件下(93.1±1.2)％降至(88±3)％(P<0.01),SOD的活性也由(0.24±0.07)kNU/L下降到(0.18±0.03)kNU/L(P>0.05),但其使内皮细胞MDA的生成由(1.12±0.06)mmol/L增至(3.78±0.03)mmol/L(P<0.01).丹酚酸B镁盐2.5,5,10 mg/L能明显降低缺氧复氧引起的内皮细胞MDA生成量的增加,并且显著提高细胞活力和SOD的活性.同时,缺氧复氧还增加内皮细胞的胞内游离钙浓度(F_(340)/F_(380)由 1.65±0.16增至 1.89±0.28)和一氧化氮释放[由(7.5±1.3)μmol/L增至(16±5)μmol/L],并上调其eNOS mRNA的表达,但降低iNOS mRNA的表达(P<0.05).但在无钙的条件下,缺氧复氧对内皮细胞的胞内游离钙浓度、一氧化氮含量、eNOSnRNA和iNOS mRNA表达     

Role of somatostatin analogs in the clinical management of non-neuroendocrine solid tumors

The somatostatin analogs octreotide, lanreotide and RC-160 (vapreotide) are known to have direct and indirect antitumor effects. Direct effects include the arrest of tumor growth and stimulation of apoptosis, resulting in tumor shrinkage. Indirect antiproliferative effects may occur through antiangiogenesis, immunomodulatory effects and the suppression of tumor-stimulating growth factors. With a safety profile of somatostatin analogs established over 20 years of clinical use in the treatment of neuroendocrine tumors, somatostatin analogs are attractive therapeutic options for patients with non-neuroendocrine tumors. In early clinical trials of somatostatin analogs, however, some cancer patients responded well, while others showed a lack of benefit. This variability in clinical response may reflect the selective binding affinities of octreotide, lanreotide and RC-160, which bind with high affinity to just two of the five different somatostatin receptor subtypes. Treatment response may therefore depend on the specific receptor subtype(s) present in the tumor, the relative proportion of receptor(s) expressed on the tumor cell surface and the absolute quantity of each receptor subtype. Greater understanding of the role of somatostatin receptors, their binding affinities and modes of action has led to increased research into the use of somatostatin analogs, particularly octreotide, in cancer treatment as monotherapies, in combination with hormonal treatments and cytotoxic therapies, and in both adjuvant and neoadjuvant settings. A review of the literature suggests that the antitumor potential of somatostatin analogs should be investigated further and additional studies might determine how these analogs can best be used to improve the treatment of patients with non-neuroendocrine tumors.     

金雀异黄素对正常的和过氧化氢损伤的内皮细胞的影响(英文)

目的 :观察金雀异黄素 (genistein)对体外培养的血管内皮细胞 (ECV 3 0 4)生长的影响和对过氧化氢引起ECV 3 0 4细胞损伤的保护作用。方法 :将ECV 3 0 4细胞与金雀异黄素 0 .1～ 1 0 0 μmol·L-1共同孵育 2 4～ 96h ,通过MTT法测定细胞存活率。为了观察金雀异黄素对过氧化氢引起ECV 3 0 4细胞损伤的保护作用 ,将细胞分成 3组 ,分别为对照组、过氧化氢损伤模型组和金雀异黄素治疗组 ,治疗组ECV 3 0 4细胞先与金雀异黄素 6.2 5～ 1 0 0 μmol·L-1共同孵育 3 0min ,然后模型组和治疗组ECV3 0 4细胞均加入过氧化氢 1 0mmol·L-1孵育 ,3 0min后以MTT法测定OD值 ,以此反映各组ECV 3 0 4的生存情况。结果 :金雀异黄素对于正常ECV 3 0 4细胞生长的作用与浓度和作用时间有关 ,浓度为1 0 0 μmol·L-1时 ,作用 2 4,48h能明显促进ECV3 0 4生长 (P <0 .0 1 ) ,而作用 96h则表现为明显的抑制作用 (P <0 .0 5 ) ;浓度为 1 0 μmol·L-1时 ,作用48,72h对ECV 3 0 4细胞生长也有促进作用 (P <0 .0 5 ) ;而当金雀异黄素浓度降低为 0 .1 ,1 μmol·L-1时 ,对ECV 3 0 4细胞生长无明显影响。过氧化氢 1 0mmol·L-1可使ECV 3 0 4的存活率明显下降(P <0 .0 5 ) ;预先给予金雀异黄素 2 5 ,5 0 ,1 0 0 μmol·L-1能浓度依赖性地     

Effect of simvastatin on endothelium-dependent vaso-relaxation and endogenous nitric oxide synthase inhibitor

AIM: To investigate the effect of simvastatin on endothelium-dependent vasorelaxation and endogenous nitric oxide synthesis inhibitor asymmetric dimethylarginine (ADMA) in rats and cultured ECV304 cells. METHODS: Endothe-lial injury was induced by a single injection of low density lipoprotein (LDL) (4 mg/kg, 48 h) in rats or incubation with LDL (300 mg/L) or oxidative-modified LDL (100 mg/L) in cultured ECV304 cells, and vasodilator responses to acetylcholine (ACh) in the aortic rings and the level of ADMA, nitrite/nitrate (NO) and tumor necrosis factor-alpha (TNF-α) in the serum or cultured medium were determined. And the adhesion of the monocytes to endothe-lial cells and the activity of dimethylarginine dimethylaminohydrolase (DDAH) in the cultured ECV304 cells were measured. RESULTS: A single injection of LDL decreased endothelium-dependent relaxation to ACh, markedly increased the serum level of endogenous ADMA and TNF-α, and reduced serum level of NO. Pretreatment with simvastatin (30 or 60 mg/kg) markedly attenuated inhibition of vasodilator responses to ACh, the increased level of TNF-α and the decreased level of NO by LDL, but no effect on serum concentration of endogenous ADMA. In cultured ECV304 cells, LDL or ox-LDL markedly increased the level of ADMA and TNF-α and potentiated the adhesion of monocytes to endothelial cells, concomitantly with a significantly decrease in the activity of DDAH and serum level of NO. Pretreatment with simvastatin (0.1, 0.5, or 2.5 μmol/L) markedly decreased the level of TNF-α and the adhesion of monocytes to endothelial cells, but did not affect the concentration of endogenous ADMA and the activity of DDAH. CONCLUSION: Simvastatin protect the vascular endothelium against the damages induced by LDL or ox-LDL in rats or cultured ECV304 cells, and the beneficial effects of simvastatin may be related to the reduction of inflammatory cytokine TNF-α level.     

灵芝多糖肽对ECV304细胞氧化损伤的保护作用

目的研究灵芝多糖肽对ECV304氧化损伤的保护作用。方法培养ECV304细胞,以叔丁基氢过氧化物(tBOOH)为氧化剂损伤细胞,造成氧化损伤模型,培养液中加入不同浓度灵芝多糖(12.5、25、50、100mg.L-1),以MTT法测细胞存活率;以光镜、电镜检测细胞形态学改变及线粒体损伤;用AnnexinV/PI双标记细胞,流式细胞检测细胞凋亡的百分率。结果灵芝多糖(12.5、25、50、100mg.L-1)可减少叔丁基氢过氧化物对ECV304的氧化损伤,MTT检测灵芝多糖给药组,ECV304细胞存活率增加。光镜下可见细胞损伤减少,电镜可见灵芝多糖(50mg.L-1,温育24h)减轻细胞器如线粒体氧化损伤,减少细胞凋亡。细胞流式检测表明:对照组、给药组、损伤组总凋亡百分率分别2.24%±0.43%、24%±6.4%(P<0.01)、82.1%±7.9%。结论灵芝多糖肽(GLPP)对ECV304细胞氧化损伤具有保护作用。