血管紧张素Ⅱ对心室肌细胞电生理特征的影响

目的:探讨血管紧张素Ⅱ诱导心肌肥大过程中心肌细胞电生理特征性改变及意义。方法:将24只新西兰兔随机分为血管紧张素Ⅱ组和正常对照组各12只,体外培养乳兔心室肌细胞,观察10-7mol/L血管紧张素Ⅱ作用48 h心肌细胞动作电位时程、瞬时外向钾电流密度的变化,并与对照组比较。结果:血管紧张素Ⅱ组心室肌细胞膜电容较正常对照组增加38.22%(P<0.01);心室肌细胞动作电位复极达90%时限较对照组延长22.1%(P<0.01);心室肌细胞瞬时外向钾电流密度较对照组下调28.6%(P<0.05)。结论:血管紧张素Ⅱ持续刺激可引起心室肌细胞电重构,可能是导致室性心律失常发生的一个重要机制。     

辛伐他汀对新生鼠脑缺氧缺血后海马区一氧化氮合酶的影响

目的探讨新生大鼠缺氧缺血脑损伤(HIBD)后海马区各型一氧化氮合酶(NOS)活性的变化及辛伐他汀对其的调节作用。方法选用7日龄SD大鼠,随机分组、建立新生大鼠HIBD模型后,于不同时间点剥取脑海马,测定各型NOS的变化并比较各组之间的差别。结果HIBD后生理盐水组诱导型NOS(iNOS)活力水平于12h时始显著增高,48h达高峰,7d时接近假手术组水平(P>0.05),12h、24h、48h、72h时胞二磷胆碱组、辛伐他汀组明显低于生理盐水组,72h时,辛伐他汀组显著低于胞二磷胆碱组(P<0.01)。生理盐水组结构型NOS(cNOS)水平于0h即显著升高,然后逐渐下降,72h时接近假手术组水平,而胞二磷胆碱组、辛伐他汀组仍继续增高,48h达高峰,但辛伐他汀组升高更显著。结论各型NOS均参与了HIBD的发病过程,辛伐他汀和胞二磷胆碱对新生大鼠HIBD的保护作用与其调节NOS有关,且辛伐他汀的作用更强。     

C57胎鼠、乳鼠及成年小鼠心室肌细胞分离、培养及鉴定

背景：培养的心肌细胞被广泛应用于心肌细胞的生理特性、毒性实验、基因工程、疾病模型和药物筛选等方面的研究。获得纯度较高活性良好的品系小鼠心肌细胞是研究的关键前提。目的：分离和培养C57小鼠胎鼠、乳鼠及成年小鼠心室肌细胞。方法：应用机械切碎心室肌后,胰蛋白酶消化不同发育阶段的C57小鼠心室肌细胞,差速贴壁1h纯化心室肌细胞,锥虫蓝染色判定心肌细胞活力,体外分别培养48～72h后分别行倒置显微镜、扫描及透射电镜观察细胞形态,微电极阵列评价细胞电生理指标,免疫组化鉴定。结果与结论：经3～6次消化后,心室组织消化完全,即刻细胞存活率大于85%。倒置显微镜下观察,细胞呈梭形、多角形。12h有少部分细胞搏动,48h细胞交织成网,搏动呈同步性,搏动频率30～90次/min。说明用胰蛋白酶组织消化法可以成功地分离、培养,并获得形态、活力良好的胎鼠、乳鼠及成年C57小鼠心室肌细胞。     

C57胎鼠、乳鼠及成年小鼠心室肌细胞分离、培养及鉴定

背景:培养的心肌细胞被广泛应用于心肌细胞的生理特性、毒性实验、基因工程、疾病模型和药物筛选等方面的研究。获得纯度较高活性良好的品系小鼠心肌细胞是研究的关键前提。目的:分离和培养C57小鼠胎鼠、乳鼠及成年小鼠心室肌细胞。方法:应用机械切碎心室肌后,胰蛋白酶消化不同发育阶段的C57小鼠心室肌细胞,差速贴壁1h纯化心室肌细胞,锥虫蓝染色判定心肌细胞活力,体外分别培养48～72h后分别行倒置显微镜、扫描及透射电镜观察细胞形态,微电极阵列评价细胞电生理指标,免疫组化鉴定。结果与结论:经3～6次消化后,心室组织消化完全,即刻细胞存活率大于85%。倒置显微镜下观察,细胞呈梭形、多角形。12h有少部分细胞搏动,48h细胞交织成网,搏动呈同步性,搏动频率30～90次/min。说明用胰蛋白酶组织消化法可以成功地分离、培养,并获得形态、活力良好的胎鼠、乳鼠及成年C57小鼠心室肌细胞。     

高迁移率族蛋白B1对大鼠脾脏树突状细胞细胞因子表达的影响

目的 观察高迁移率族蛋白B1(HMGB1)对树突状细胞(dendritic cells,DC)细胞因子蛋白合成和基因表达的影响.方法 分离正常Wistar大鼠脾脏DC后置于96孔培养板(1×105/孔),给予重组HMGB1刺激,研究HMGB1刺激与TNF-α,IL-12蛋白合成和基因表达的时间-效应关系,24孔细胞随机分为6组:正常对照24 h组(4孔/组)、正常对照48 h组(4孔/组)、正常对照72 h组(4孔/组)、HMGB1 24 h组(4孔/组)、HMGB1 48 h组(4孔/组)和HMGB1 72 h组(4孔/组),后3组分别以1 μg/mLHMGB1 刺激.刺激相应时间检测TNF-α,IL-12 mRNA的表达和蛋白水平.研究HMGB1刺激与TNF-α,IL-12蛋白合成和基因表达的剂量-效应关系,16孔细胞随机分为4组:正常对照组(4孔/组)、0.1μg/mL组(4孔/组)、1 μg/mL组(4孔/组)和10 μg/mL组(4孔/组),分别以相应剂量HMGB1刺激.刺激后48 h后检测TNF-α、IL-12 mRNA的表达和蛋白水平.应用Promega公司mRNA提取试剂盒裂解收集的DC,提取细胞mRNA.采用SYBR Green real-time(实时荧光定量)PCR技术检测TNF-α mRNA,IL-12mRNA表达水平.以三磷酸甘油脱氢酶(GAPDH)作为内参对照.扩增产物经Fast 7500 real-time PCR仪处理,作相对定量(RQ)分析.以ELISA试剂盒检测各组上清中IL-12,TNF-α蛋白水平.数据进行单因素方差分析,以P<0.05为差异具有统计学意义.结果 1 μg/mL HMGB1 刺激后,脾脏DC IL-12,TNF-α蛋白合成和基因表达均分别于24～72 h明显上调(P<0.05或P<0.01),其中以作用48 h后其表达上调尤为显著(P<0.01);0.1/.μg/mL,1 tcVmL,10μg/mL HMGB1刺激48 h均可诱导DC IL-12、TNF-α蛋白合成和基因表达增强(P<0.01),其中HMGB1浓度在1 μg/mL时,DC IL-12和TNF-α蛋白合成和基因表达表达最明显(P<0.01).结论 HMGB1诱导DC成熟分化过程中能促进DC合成、释放IL-12和TNF-α,从而发挥其免疫调节作用.     

补肾活血方对hPTH(1-34)干预下小鼠成骨细胞MC3T3-E1增殖及分化的影响

目的 观察补肾活血方含药血清对hPTH(1-34)干预后小鼠成骨细胞MC3T3-E1增殖及分化的影响.方法 制备中药、西药含药血清,用MTT法在细胞培养的24 h、48 h、72 h分别检测不同浓度补肾活血方组对hPTH(1-34)干预下MC3T3-E1增殖的作用.用ELISA方法在细胞培养的24 h、48 h、72 h分别检测不同浓度补肾活血含药血清组细胞在hPTH(1-34)干预下其上清液中Ⅰ型前胶原羧基端肽(PICP)和碱性磷酸酶(ALP)分泌水平.结果 48 h始,中药高浓度组细胞增殖水平明显高于模型PTH组(P<0.01),当达到72 h时,各浓度中药组细胞增殖水平均显著高于模型PTH组(P<0.01);48 h始至72 h,各浓度中药含药血清组ALP分泌量均显著高于模型PTH组(P<0.01);而中药高浓度组在72 h时PICP分泌量显著高于模型PTH组(P<0.01).结论 补肾活血方能促进hPTH干预下成骨细胞MC3T3-E1增殖的同时,也能很好地促进其进一步分化成熟,进而改善甲状旁腺功能亢进作用下成骨细胞的骨代谢作用,促进成骨细胞骨形成.     

大豆磷脂脂质体对FeSO4／Cysteine引起培养心肌细胞损伤的保护效应

目的:观察大豆磷脂脂质体的累积对FeSO4/Cysteine体系产生羟自由基引起心肌细胞损伤的保护作用。方法:①实验于2003-10/2004-07在锦州医学院生物化学实验室完成。选用新生两三天清洁级SD大鼠的乳鼠10～15只,取心肌细胞进行原代培养48h后,随机分成3组:正常对照组、损伤组和大豆磷脂脂质体保护组。损伤组加入FeSO4/Cysteine(终浓度FeSO41×10-3mol/L Cysteine5×10-4mol/L)作用于培养的乳鼠心肌细胞12h。大豆磷脂脂质体保护组在加入损伤因素的同时加入不同质量浓度的大豆磷脂脂质体(0.2,0.4,0.8,1.6g/L)。②测定心肌细胞培养液中乳酸脱氢酶的活力,心肌细胞中丙二醛的含量和超氧化物歧化酶的活力,均参照南京建成生物工程研究所提供的试剂盒说明书进行。培养心肌细胞线粒体内琥珀酸脱氢酶的活力采用甲基四唑蓝比色测定。结果:①培养液中乳酸脱氢酶的活力:损伤组显著高于正常对照组(P<0.01)。大豆磷脂脂质体保护各组均低于损伤组(P<0.01)。②培养心肌细胞中丙二醛的含量:损伤组显著高于正常对照组(P<0.01)。大豆磷脂脂质体保护各组均低于损伤组(P<0.01)。③培养心肌细胞中超氧化物歧化酶的活力:损伤组显著低于正常对照组(P<0.01)。大豆磷脂脂质体保护各组均高于损伤组(P<0.01)。④心肌细胞线粒体内琥珀酸脱氢酶的活力:损伤组显著低于正常对照组(P<0.01)。大豆磷脂脂质体保护各组均高于损伤组(P<0.01)。⑤大豆磷脂脂质体保护作用在一定浓度范围(0.2～0.8g/L)随着浓度的升高而增强,但剂量达到一定浓度,大豆磷脂脂质体保护作用不再随着浓度的升高而增强。结论:大豆磷脂脂质体对FeSO4/Cysteine体系产生的羟自由基引起的心肌细胞损伤具有明显的保护作用,且存在大豆磷脂脂质体浓度依赖性。     

缺氧诱导因子-1对心肌细胞缺氧/复氧损伤的保护作用

目的:观察缺氧诱导因子-1对心肌细胞缺氧复氧损伤的保护作用。方法:取SD新生大鼠(1～3 d)分离培养成心肌细胞;在培养的第3 d将心肌细胞随机分为3组(每组重复6次):正常对照组、H/R组、DMOG+H/R组;建立缺氧/复氧损伤模型,以脯氨酸羟化酶的抑制剂甲基异二酰基甘氨酸进行干预;采用酶免疫法检测各组心肌细胞培养上清液中的肌钙蛋白I含量,采用RT-PCR法检测各组缺氧诱导因子-1α及下游因子血红素氧合酶-1、血管内皮生长因子、葡萄糖转运蛋白1 mRNA水平。结果:培养4～6 h的乳鼠心肌细胞开始贴壁生长,12～24 h明显增殖,3～4 d后细胞融合成片;心肌细胞由圆形变为梭形、星形、多角形,并出现自发性节律性搏动;与正常对照组相比,H/R组、DMOG+H/R组的肌钙蛋白I含量明显增高(P<0.01),且缺氧诱导因子-1α、下游因子血红素氧合酶-1、血管内皮生长因子、葡萄糖转运蛋白1水平明显增高(P<0.01,P<0.05);与H/R组相比,DMOG+H/R组心肌细胞缺氧诱导因子-1α、下游因子血红素氧合酶-1、血管内皮生长因子、葡萄糖转运蛋白1水平明显增高而肌钙蛋白I含量明显降低(P<0.05)。结论:本...     

谷氨酰胺对脓毒症大鼠心肌细胞Bcl-2/Bax表达的影响

目的 研究脓毒症大鼠心肌细胞凋亡与Bcl-2/Bax基因及蛋白表达的关系,探讨谷氨酰胺(Gin)对脓毒症心肌细胞凋亡的保护作用.方法采用内毒素(LPS 4 ms/ks)腹腔注射法制作脓毒症大鼠模型,实验地点在中山大学北校区动物实验中心.健康Sprague-Dawley(sD)大鼠72只随机分为对照组、LPS组及LPS+Gln(0.3g/kg)组,再分为0 h,6 h,12 h,24 h亚组(腹腔注射后每组成功存活至观察时间点的大鼠累积达到6只,n=6),检测各时点心肌细胞凋亡率和Bcl-2及Bax蛋白的含量,同时检测心肌Bcl-2及Bax mRNA表达.对结果进行方差分析和相关性统计分析.结果 LPS组大鼠心肌细胞凋亡率6 h、12 h及24 h均明显高于埘照组(F=186.786,P<0.01);心肌细胞Bax蛋白表达术后6 h降低(F=9.027,P<0.01),之后高于对照组;而Bcl-2蛋白表达6 h,12 h及24 h均低于对照组(F=301.142,P<0.01);Bax/Bcl-2蛋白表达比明显高于对照组(F=527.373,P<0.01);BaxmRNA和Bcl-2 6 h,12 h及24 h较对照组均明显上调(F=126.157,80.745,P<0.01).LPS+Gln组与LPS组比较,6 h,12 h及24 h心肌细胞凋亡率明显低于LPS组(F=75.187,P<0.01);Bax蛋白表达下降(F=20.981,P<0.01),而Bcl-2蛋白却升高(F 164.969,P<0.000);Bax/Bcl-2蛋白表达比降低(F=141.426,P<0.01);Bax mRNA和Bcl-2 6 h,12 h及24 h组较LPS组均明显下调(F=103.463,89.373,P<0.01).结论 Bcl-2抗凋亡基因及Bax促凋亡基因及其蛋白的表达参与脓毒症心肌细胞凋亡;应用Gln能影响凋亡相关基因及蛋白表达,减轻脓毒症心肌细胞的凋亡,改善脓毒症预后.     

替米沙坦对胰岛素抵抗大鼠心肌细胞脂联素受体的作用

目的观察替米沙坦对心肌细胞脂联素(APN)受体的影响,从而探讨胰岛素抵抗中心肌脂联素受体表达可能的调控机制。方法应用高果糖饮食造模成功的胰岛素抵抗(IR)大鼠,采用酶解法分离出心室肌细胞,进行原代细胞培养,将心室肌细胞分为两组:对照组予二甲基亚砜(DMSO)刺激24 h,替米沙坦组予DMSO+替米沙坦10μM/L刺激24 h。培养心肌细胞24 h后采用酶联免疫吸附法(ELISA)测定两组心室肌细胞培养液中APN的生成。采用Western Blot法测定不同处理后心肌细胞脂联素受体1(AdipoR1)、受体2(AdipoR2)、过氧化物酶体增殖物激活受体γ(PPARγ)、肿瘤坏死因子α(TNF-α)蛋白的表达。结果与对照组相比,替米沙坦组心室肌细胞培养液中脂联素的浓度增高(P<0.05)。与对照组相比,替米沙坦组心肌细胞AdipoR1蛋白的表达增高(P<0.05),而心肌细胞AdipoR2蛋白的表达无明显变化(P>0.05);心肌细胞PPARγ蛋白的表达增高(P<0.05),心肌细胞TNF-α蛋白的表达降低(P<0.05)。结论替米沙坦可以通过激活PPARγ提高胰岛素抵抗大鼠心肌细胞脂联素受体表达,减轻炎症,改善心肌代谢。脂联素及AdipoR1可能是其发挥作用的目标蛋白之一。     

Iron uptake from rat plasma transferrin by rat reticulocytes.

Fast and slow rat transferrins were isolated by isoelectric focusing and prepared in their di- and monoferric forms. A comparison of the rates of iron release between fast and slow monoferric transferrins when incubated with reticulocytes or injected in vivo showed no significant difference in the behavior of the two isotransferrin species. Reticulocyte uptake of diferric transferrin resulted in the removal of both iron atoms from the transferrin molecule. A twofold greater iron uptake was observed from diferric as compared with monoferric iron, provided reticulocyte receptors were saturated. It is concluded that the two species of transferrin and their individual sites function similarly in their release of iron to tissue receptors.     

青老年大鼠脑缺血模型的比较

背景:大鼠具有成本低,种系内纯合性好,脑血管解剖特性与人类相似等特点,是目前脑缺血研究最常用的实验动物。目的:观察青老年大鼠大脑中动脉梗死后的行为学变化,分析年龄对脑缺血的影响。方法:将青、老年SD大鼠随机分为青、老年假手术组,青、老年模型组(同侧颈总动脉永久结扎大脑中动脉线栓法制备大脑中动脉梗死模型)4组。结果与结论:老年假手术组体质量低于青年假手术组(P<0.05),但高于老年模型组(P<0.05),老年模型组体质量低于青年模型组(P<0.05)。术后第1,3,5,7天老年模型组改良神经功能损害程度评分高于青年模型组(P<0.05);与青年模型组及青、老年假手术组比较,术后第3,8,12周老年模型组逃避潜伏期明显延长,跨过平台所在位置的次数明显减少(P<0.05)。表明在同等缺血打击下,老龄鼠脑缺血模型缺血损伤重、修复能力低,其神经功能恢复、学习和记忆能力明显逊于青年大鼠,提示增龄因素是研究脑缺血后神经损伤的重要影响因素之一。     

Catabolism of rat beta2-microglobulin in the rat.

Highly purified rat beta2-microglobulin (beta2m) as well as cytochrome c and lysozyme were radiolabeled and their catabolism studied in the rat. More than 90 percent of these low molecular weight proteins were removed from the serum within an hour and excreted into the urine by 24 hours. Except for the kidney in which the concentration of these protein is ten- to twentyfold greater than in the serum, there is little evidence that rat tissues are concentrating these proteins. The stomach was found to concentrate radioiodine. The catabolism of rat beta2m differed from that of cytochrome c and lysozyme in that the kidney contained twice as much labeled rat beta2m. In addition, the rat excretes 10 to 15 percent of the injected rat beta2m but only 1 to 5 percent of the cytochrome c or lysozyme. These studies established a basis for turnover studies of beta2m complexed with other cell membrane proteins, for example, HL-A or H-2 peptides.     

Cardiovascular effects of rat calcitonin gene-related peptide in the conscious rat

The role of rat calcitonin gene-related peptide (CGRP), a recently characterized vasoactive neuropeptide, in cardiovascular regulation was studied in the conscious rat. Mean arterial pressure (MAP), heart rate, cardiac output (thermodilution technique) and regional blood flow (directional pulsed Doppler velocimetry) were monitored after i.v. or i.c.v. administration of CGRP. Systemic administration of CGRP (0.1-10 nmol/kg i.v.) decreased MAP and increased heart rate in a dose-related manner. Cardiac output increased (+95 +/- 16 ml/min/kg, P less than .01) after the 1-nmol/kg dose. At the lower or higher doses, CGRP produced no consistent changes in cardiac output. Total peripheral resistance was decreased significantly at the doses of 1 and 10 nmol/kg of CGRP. The CGRP i.v. doses of 1 and 10 nmol/kg increased mesenteric and hindquarter blood flow to a maximum of +23 +/- 7 and +30 +/- 6%, respectively (P less than .01). An increase in renal blood flow (+19 +/- 6%, P less than .05) and a decrease in renal resistance (-15 +/- 4%, P less than .05) were produced by the 0.1-nmol/kg dose of CGRP which had no effect on MAP; higher doses of CGRP tended to decrease renal blood flow. The resistance in all vascular beds was decreased by the CGRP doses of 1 and 10 nmol/kg. The maximum decreases in mesenteric, renal and hindquarter vascular resistance after the 10-nmol/kg dose were -53 +/- 3, -42 +/- 5 and -48 +/- 4%, respectively (P less than .01). The hypotensive and vasodilator responses to CGRP i.v. were significantly magnified, and the tachycardia produced by CGRP was attenuated in the sinoaortic denervated rats. Atropine (muscarinic blockers), propranolol (beta adrenoceptor blocker), cimetidine and pyrilamine (histamine H1 and H2 blockers), indomethacin (prostaglandin synthesis inhibitor), BN52021 (platelet activating factor antagonist) or a substance P antagonist had no effect on the cardiovascular responses elicited by systemic CGRP. CGRP, i.c.v. (0.1-10 nmol/kg), induced a modest tachycardia in both intact and sinoaortic denervated rats, but was devoid of any other cardiovascular effects. The results indicate that CGRP is a potent vasodilator of mesenteric, renal and hindquarter skeletal muscle blood vessels in the conscious rat. The hypotensive and vasodilator actions of circulating CGRP are likely to be mediated by direct peripheral interaction with CGRP receptors on vascular smooth muscle, whereas its tachycardic effect seems to involve reflex activation of the sympathetic nervous system.     

Extraction of an inhibitory substance from rat liver on rat brain ATPase.

A substance, which can be extracted from rat liver and partially purified, has been tested for its effect on the activity of ATPase in rat brain. This substance inhibited the ATPase activity significantly, and the inhibitory effect was not eliminated by the addition of catecholamines such as epinephrine and dopamine.     

Direct action of rat urinary kallikrein on rat kidney to release renin.

To study the effect of kallikrein on renal renin release, we superfused rat renal cortical slices with 3.5 to 140 milliesterase units (mEU)/ml of purified rat urinary kallikrein. Kallikrein was a potent stimulus of renin release. Renin rose in a dose-dependent fashion from 70 mEU/ml to 140 mEU/ml. The response to 140 mEU/ml was greater than that seen with maximal doses of prostaglandin E2 (170 +/- 43%, P < 0.05) and at least the same as isoproterenol (242 +/- 49% increase), or dibutyryl cyclic AMP (272 +/- 40%). Trypsin was ineffective under these experimental conditions. Kallikrein-stimulated renin release was completely abolished by trasylol, whereas bradykinin did not increase renin production, indicating that kallikrein's effect is not mediated via kinin generation. There was no demonstrable acid activation or kallikrein activation of the superfusate and chromatography on Sephacryl S-200 revealed a single renin peak of -40,000 mol wt, suggesting that all of the renin release was in the active form. The data suggests that urinary kallikrein acts directly on the rat kidney to release renin, possibly via proteolytic conversion of prorenin to active renin. Our results support the concept that kallikrein may be an endogenous activator of prorenin in the kidney.     

Effects of rat interleukin-2 and rat interferon on the natural killer cell activity of rat spleen cells after thermal injury.

The natural killer cell activity of splenocytes from rats with scald injury was observed to be significantly suppressed at 7 days after injury compared with that of normal nonburned controls. Incubation of splenocytes from normal rats or rats with burn injury with either rat interleukin-2 or rat interferon (IFN-alpha and IFN-beta) significantly increased the natural killer cell activity. Addition of a rabbit anti-rat interferon antibody to spleen cells incubated with interleukin-2 did not produce any significant alteration in interleukin-2-related enhancement of natural killer cell activity. These results suggest that enhancement of natural killer cell activity after incubation of splenocytes with interleukin-2 is not due to interferon production but is an independent event. Preincubation of spleen cells with a mouse monoclonal antibody to rat interleukin-2 receptor was observed to abolish the interleukin-2-related enhancement of natural killer cell activity completely, whereas it partially blocked the interferon-related enhancement. These results were also confirmed by enhancement of natural killer cell activity of burned rats after in vivo administration of interleukin-2. Our studies thus indicate that after thermal injury, the observed decrease of natural killer cell activity can be enhanced by both interleukin-2 and interferon independently of each other. The decreased natural killer cell activity may be due to a decrease in interleukin-2 production or availability and not to an interleukin-2 receptor defect. These studies thus point toward a potential therapeutic significance of interleukin-2 in enhancing immune function after thermal injury.