细胞色素P450基因降低动脉粥样硬化小鼠MMP-9表达

目的研究血管内皮高表达CYP2C8基因能否降低动脉粥样硬化小鼠的MMP-9的表达。方法以20周龄APOEKO+/-CYP2C8Tg+/-和CYP2C8Tg+/-小鼠(n=10/组)为研究对象,相同基因背景和周龄的同窝APOEKO+/-和C57BL/6小鼠设为对照。采用PCR技术鉴定小鼠CYP2C8+/-基因;油红O染色检测APOEKO+/-CYP2C8Tg+/-、CYP2C8Tg+/-、APOEKO+/-和C57BL/6小鼠主动脉斑块形成面积;用Real-time PCR法检测各组小鼠的主动脉MMP-9基因表达水平,Western blot分析各组小鼠的主动脉MMP-9蛋白的表达情况。用ELISA法检测各组小鼠的血浆IL-1β和IL-10。结果 APOEKO+/-CYP2C8Tg+/-和CYP2C8Tg+/-小鼠主动脉斑块形成面积明显减少,Real-time PCR分析显示高表达CYP2C8在主动脉中明显下调MMP-9基因的表达,Western blot分析结果显示:高表达CYP2C8在主动脉中明显下调MMP-9蛋白的活性。在血清学上,高表达CYP2C8明显上调IL-10而下调IL-1β。结论高表达CYP2C8基因能够降低小鼠的MMP-9的活性、减低炎性介质水平,通过抗炎和稳定粥样斑块而发挥抗粥样硬化作用。     

细胞色素P450基因对高脂饮食诱导不同周龄小鼠动脉粥样硬化的保护作用

目的研究血管内皮高表达CYP2C8基因能否改善小鼠动脉粥样硬化。方法以20和40周龄APOEKO+/-CYP2C8Tg+/-和CYP2C8Tg+/-基因(血管内皮特异性CYP2C8+/-转基因)的小鼠(n=10/组)为研究对象,相同基因背景和周龄的同窝APOEKO+/-和C57BL/6小鼠设为对照。采用PCR技术鉴定小鼠CYP2C8+/-基因;油红O染色检测APOEKO+/-CYP2C8Tg+/-、CYP2C8Tg+/-、APOEKO+/-和C57BL/6小鼠主动脉斑块形成面积;酶比色检测APOEKO+/-CYP2C8Tg+/-、CYP2C8Tg+/-、APOEKO+/-和C57BL/6小鼠血清TG、TCH、HDL。结果 20和40周龄APOEKO+/-CYP2C8Tg+/-和CYP2C8Tg+/-小鼠主动脉斑块形成面积与同周龄野生型小鼠相比明显减少,并且明显改善了血脂代谢状态。结论高表达CYP2C8基因能够改善西方饮食诱导的不同周龄小鼠的动脉粥样硬化。     

细胞色素P450 4F2基因的克隆、突变、表达和纯化

目的构建人细胞色素P450 4F2基因野生型、V81G和V433M突变型表达载体,在大肠杆菌中表达并纯化出CYP4F2蛋白。方法用RT-PCR方法从人肾脏总RNA中逆转录扩增CYP4F2,将其插入克隆载体pMD18-T Simple Vector中,将测序鉴正确的CYP4F2基因N、C端改造,克隆构建重组表达载体pCWori -CYP4F2(His)_4-WT。同时采用重叠PCR定点突变法构建pCWori -CYP4F2 V81G(His)_4和pCWori -CYP4F2 V433M(His)_4表达载体,分别转化至E.Coli XL-Blue中表达。结果经IPTG诱导可有效表达CYP4F2和突变体V81G与V433M,经Western blot分析可以观察到分子量为57 kD的诱导表达条带,该表达蛋白可与His-Probe多克隆抗体起特异反应。用His- bind亲和层析纯化得到了纯度较高的His融合蛋白。结论用基因工程技术在大肠杆菌中有效表达人CYP4F2基因野生型、V81G和V433M突变型蛋白、并得到了纯度较高的CYP4F2蛋白,为进一步研究其生物学功能及研制相应抗体奠定了基础。     

养心氏片对动脉粥样硬化模型小鼠的作用机制研究

目的探讨养心氏片治疗动脉粥样硬化(AS)的可能作用机制。方法以高脂饲料喂养雄性载脂蛋白E基因敲除(ApoE~(-/-))小鼠12周,复制AS模型。将AS小鼠随机分成模型组,养心氏片高剂量组、中剂量组、低剂量组及阳性对照组,每组8只。另设雄性C57BL/6J小鼠8只作为正常对照组。养心氏片高剂量组、中剂量组、低剂量组及阳性对照组给药量分别相当于70 kg成人临床剂量的2倍、1倍、0.5倍及1倍。养心氏片高剂量组、中剂量组、低剂量组给予养心氏片,剂量分别为1.40 g/(kg·d)、0.70 g/(kg·d)、0.35 g/(kg·d)灌胃,阳性对照组给予阿托伐他汀剂量为2.57 mg/(kg·d)灌胃,共给药12周。采用苏木素-伊红(HE)染色法观察小鼠升主动脉病理学变化,Image J软件测定小鼠升主动脉斑块校正后斑块面积。采用实时定量PCR(qPCR)法检测各组小鼠主动脉组织核转录因子-κB(NF-κB)、单核细胞趋化蛋白-1(MCP-1)、血管内皮细胞黏附分子-1(VCAM-1)、白介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)mRNA的表达。结果与模型组比较,养心氏片高剂量组、中剂量组、低剂量组及阳性对照组升主动脉斑块校正后斑块面积呈现不同程度的降低(P0.05),以养心氏片高剂量组小鼠升主动脉斑块校正后斑块面积最低,而养心氏片高剂量组小鼠升主动脉斑块校正后斑块面积与阳性对照组相比差异无统计学意义(P0.05)。与正常对照组比较,模型组小鼠主动脉组织NF-κB、MCP-1、VCAM-1、IL-6、TNF-αmRNA的表达水平明显升高(P0.05),各药物干预组小鼠主动脉组织NF-κB、MCP-1、VCAM-1、IL-6、TNF-αmRNA表达水平较模型组均显著降低(P0.05),与养心氏片高剂量组相比,养心氏片中剂量组及低剂量组小鼠主动脉NF-κB、MCP-1、VCAM-1、IL-6、TNF-αmRNA表达升高(P0.05),而养心氏片高剂量组小鼠主动脉NF-κB、MCP-1、VCAM-1、IL-6、TNF-αmRNA表达与阳性对照组相比差异无统计学意义(P0.05)。结论养心氏片可抗动脉粥样硬化,并具有剂量依赖性,养心氏片给药组以养心氏片高剂量组抗AS效果最佳,其机制可能与降低AS小鼠升主动脉斑块校正后斑块面积及下调主动脉NF-κB信号通路相关因子mRNA表达有关。     

Exendin-4对高脂饮食载脂蛋白E基因敲除小鼠脂代谢及炎症因子的影响

目的观察Exendin-4对高脂饮食载脂蛋白E基因敲除(ApoE^-/-)小鼠脂代谢、白细胞介素-6(IL-6)、单核细胞趋化蛋白-1(MCP-1)及血管内皮细胞黏附分子-1(VCAM-1)表达的影响。方法将40只雄性ApoE^-/-小鼠随机分为普通饮食组(10只)和高脂饮食组(30只),喂养8周后再将高脂饮食组分为非药物干预组、Exendin-4低剂量组、Exendin-4高剂量组,每组10只。Exendin-4低剂量组、Exendin-4高剂量组ApoE^-/-小鼠分别给予20μg/(kg·d)、100μg/(kg·d)Exendin-4腹腔内注射;普通饮食组、非药物干预组ApoE^-/-小鼠给予0.1 mL生理盐水腹腔内注射。第12周末处死小鼠,进行相关检测,采用全自动生化分析仪检测小鼠总胆固醇(TC)、三酰甘油(TG)、低密度脂蛋白胆固醇(LDL-C)及高密度脂蛋白胆固醇(HDL-C)水平;RT-PCR及Western Blot法分别检测主动脉IL-6、MCP-1及VCAM-1 mRNA和蛋白表达水平;酶联免疫吸附试验(ELISA)检测血浆中IL-6、MCP-1及VCAM-1水平。结果与普通饮食组相比,非药物干预组ApoE^-/-小鼠TC、LDL-C水平明显升高(P<0.01),应用Exendin-4干预后,Exendin-4高剂量组TC、LDL-C水平明显降低(P<0.05或P<0.01);各组小鼠血清中TG、HDL-C含量虽有变化,但差异无统计学意义(P>0.05)。与非药物干预组相比,Exendin-4处理可以降低主动脉IL-6、MCP-1及VCAM-1 mRNA及蛋白表达,同时下调血浆中IL-6、MCP-1及VCAM-1蛋白水平,差异均有统计学意义(P<0.05或P<0.01)。结论Exendin-4可以改善高脂饮食ApoE^-/-小鼠脂代谢并降低主动脉IL-6、MCP-1及VCAM-1的表达。     

慢性压力负荷所致心肌肥厚及心衰大鼠左心室肌ERK的动态变化

目的　研究大鼠从正常、心脏肥大到心衰时的细胞外信号调节激酶 (L ERK)表达及活性变化。方法　环扎幼年 wistar大鼠的升主动脉 ,造成慢性压力负荷引起左室肥厚及心衰的动物模型 ,用 Western Blot方法测定各组大鼠的 ERK表达及活性。结果　 32 w对照组与 1 6 w对照组大鼠比较 ,ERK1、ERK2、p- ERK1、p- ERK2蛋白表达水平均无明显差别。左室肥大及心衰大鼠左室肌 ERK及 p- ERK表达水平较对照组均明显增高 ,而心衰大鼠 p- ERK表达水平较左室肥大组明显降低 ,但 ERK表达变化不明显 ;在左室肥大组 ,p- ERK表达水平与心室肥大的程度呈正相关。结论 :慢性压力负荷引起左心肥大 ,ERK活性明显增加 ,但随着心衰的发生逐渐降低 ;ERK活性从升高到降低的变化预示着心脏功能从代偿到失代偿的转变     

基于血脂代谢紊乱理论研究血管软化丸抗动脉粥样硬化的作用机制

目的观察血管软化丸对载脂蛋白E基因敲除(ApoE-/-)小鼠血脂、血液流变学指标、血小板活化标志物CD63表达、主动脉粥样斑块病理形态及病灶处核转录因子-κB(NF-κB)的影响。方法采用高脂饲料喂饲ApoE-/-小鼠,60只ApoE-/-小鼠随机分为4组,正常对照组喂普通饲料,其他各组喂养饲高脂饲料建立动脉粥样硬化模型,各组按规定连续灌胃8周后测定血清血脂水平[总胆固醇(TC)、三酰甘油(TG)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)],血液流变学指标(全血黏度、血浆黏度、红细胞聚集指数)、血小板活化标志物CD63表达、主动脉粥样斑块病理形态及病灶处NF-κB的含量。结果高脂饮食引起小鼠血脂及血液流变学指标显著升高,导致ApoE-/-小鼠主动脉粥样斑块形成。与模型组比较,血管软化丸组TC、TG、LDL-C水平降低(P 0.05),HDL-C升高(P 0.05);全血低、中、高切黏度、血浆黏度、红细胞聚集指数降低(P 0.05)。各组小鼠主动脉斑块出现不同程度的染色强阳性,中药组平均光密度值较辛伐他汀组明显减小(P 0.05)。结论血管软化丸通过调控高脂饮食引起的血脂代谢紊乱及异常血液流变学指标,降低血小板活化标志物CD63表达和周围血管壁NF-κB含量,起到抗动脉粥样硬化的作用。     

增龄和高血压经PI3K/Akt和MAPK信号通路间平衡介导调控血管平滑肌细胞的表型转换

目的探究增龄和高血压对胸主动脉血管平滑肌细胞(VSMC)表型转换的影响及磷脂酰肌醇激酶(PI3K/Akt)和丝裂原活化蛋白激酶(MAPK)信号通路对VSMC表型的调控。方法选取1、3、9、16月龄的雄性Wistar Kyoto大鼠(WKY)和自发性高血压大鼠(SHR)各12只,尾动脉无创测定血压,取各组大鼠的胸主动脉进行实验。HE染色测量胸主动脉的管壁厚度;免疫组织化学染色检测VSMC表型标志蛋白α平滑肌肌动蛋白(α-SMactin)、调宁蛋白、骨桥蛋白(OPN)的表达和分布;Western blot检测VSMC表型标志蛋白α-SM-actin、调宁蛋白、OPN及信号蛋白p-Akt、内皮型一氧化氮合酶(eNOS)、p-42/44ERK、p-p38MAPK的表达量。结果 HE染色结果显示,增龄导致管壁厚度增加,且在9月龄时WKY和SHR出现显著差异(P0.01)。免疫组织化学染色和Western blot结果表明,3月龄后,WKY和SHR的α-SM-actin、调宁蛋白表达量随月龄增加出现下调,而OPN出现上调;p-Akt、eNOS的蛋白表达量随月龄增加逐渐下调,p-42/44ERK、p-p38MAPK蛋白表达量随月龄增长逐渐上调,且3月龄时两组已有显著差异(P0.01)。结论增龄和高血压均导致大鼠胸主动脉VSMC收缩表型标志蛋白α-SM-actin、调宁蛋白的表达下调,合成表型标志蛋白OPN的表达上调,二者的交互作用更显著。VSMC的表型转换可能是通过PI3K/Akt和MAPK信号通路间的平衡作用进行调控的。     

2型糖尿病大鼠胸主动脉磷酸化p38丝裂素活化蛋白激酶蛋白表达及利拉鲁肽对其干预作用的研究

目的探讨p38丝裂素活化蛋白激酶(MAPK)与糖尿病大血管病变的关系及利拉鲁肽对其的干预作用。方法 24只Wistar大鼠分为正常对照组(NC)和实验组(EXP)。EXP组予高糖高脂饮食联合小剂量STZ腹腔注射建立T2DM大鼠模型。将成模大鼠随机分为糖尿病组(DM)和利拉鲁肽组(LIR),每组各7只。LIR组予利拉鲁肽(100μg/kg,2次/d)皮下注射,共8周;DM组和NC组予等量生理盐水皮下注射。实验结束后,测定各组相关指标;HE染色观察胸主动脉形态,免疫组织化学法检测胸主动脉磷酸化p38MAPK、核因子-κB(NF-κB)和单核细胞趋化蛋白-1(MCP-1)蛋白表达水平。结果 HE染色可见DM组胸主动脉呈动脉粥样硬化表现。DM组胸主动脉磷酸化p38MAPK、NF-κB和MCP-1蛋白表达水平较NC组升高(P=0.000),LIR组较DM组降低(P=0.017)。Spearman相关分析显示,胸主动脉磷酸化p38 MAPK与NF-κB、MCP-1蛋白表达呈正相关。DM组血糖、TG、TC、LDL-C、血清细胞间黏附分子-1(ICAM-1)、血管内皮黏附分子-1(VCAM-1)、NF-κB水平较NC组升高(P=0.000),较LIR组降低(P0.01)。结论在大鼠实验中,p38MAPK信号通路参与了糖尿病大血管病变的发生;利拉鲁肽可能通过下调血管p38MAPK磷酸化水平、抑制炎症反应、调脂等发挥了对糖尿病大血管病变的保护作用。     

miR-301a调节小鼠巨噬细胞中炎症因子的表达

目的探讨miR-301a对巨噬细胞炎症因子表达水平的影响,从microRNA角度阐明动脉粥样硬化的发病机制,为动脉粥样硬化的防治提供新的思路。方法高脂喂养Apo E-/-小鼠建立动脉粥样硬化模型,收集小鼠主动脉血管,利用real-time PCR检测组织中miR-301a的表达水平;利用脂质体在RAW264.7细胞中转染miR-301a mimic和miR-301a inhibitor,用real-time PCR检测细胞中miR-301a水平,并检测肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)和单核细胞趋化蛋白1(MCP-1)的表达水平,用Western blot检测NF-κB抑制因子(NKRF)蛋白水平,用免疫荧光染色检测p65细胞定位。结果在高脂喂养的Apo E-/-小鼠主动脉血管壁组织中miR-301a的表达水平升高;在RAW264.7细胞中过表达miR-301a可抑制NKRF蛋白水平,促进p65细胞核定位,升高细胞中TNF-α、IL-6和MCP-1的mRNA表达;在RAW264.7细胞中低表达miR-301a可升高NKRF蛋白水平,促进p65细胞质定位,减少细胞中TNF-α、IL-6和MCP-1的mRNA表达。结论在高脂喂养的Apo E-/-小鼠主动脉血管壁组织中miR-301a表达水平升高;在RAW264.7细胞中miR-301a通过调节NKRF的表达影响p65活性进而调控TNF-α、IL-6和MCP-1的mRNA表达,提示microRNA在动脉粥样硬化发病的炎症机制中具有重要作用。     

Decreased arteriolar density in endothelial nitric oxide synthase knockout mice is due to hypertension, not to the constitutive defect in endothelial nitric oxide synthase enzyme

BACKGROUND : Hypertension in endothelial nitric oxide synthase knockout (eNOS-/-) mice is believed to be partly due to altered vasodilatation. However, nitric oxide (NO) is also known to play an important part in angiogenesis. OBJECTIVE : To investigate whether capillary and arteriolar density were impaired in eNOS-/- mice, as this could account for increased vascular resistance and hypertension. METHODS : Using immunohistochemistry with mouse monoclonal smooth muscle alpha-actin antibody to detect arterioles and rabbit polyclonal fibronectin antibody to detect capillaries, we quantified arteriolar and capillary density in the left ventricle and in the gracilis muscle from eNOS-/- mice compared with those in C57BL6J littermates (n = 6-8) in 8- and in 12-week-old mice. In a second set of experiments, we treated 8-week-old normotensive eNOS-/- mice with the antihypertensive vasodilator, hydralazine, for 1 month. RESULTS : Eight-week-old eNOS-/- mice were normotensive and presented similar arteriolar and capillary densities in cardiac and skeletal muscles compared with those in eNOS+/+ mice. Twelve-week-old eNOS/- mice were hypertensive (mean arterial pressure 118 +/- 21 mmHg compared with 64 +/- 2 mmHg; P < 0.05). Capillary densities were similar in eNOS-/- mice and eNOS+/+ mice in the heart (4154 +/- 123 and 4051 +/- 247/mm2, respectively) and in skeletal muscle (961 +/- 40 and 1025 +/- 41/mm2, respectively). Arteriolar densities were 15% lower in skeletal muscle and in the heart in eNOS-/- mice than in the eNOS+/+ control group (P < 0.05). Hydralazine prevented hypertension and arteriolar rarefaction in eNOS-/- mice, whereas capillary density was unaffected by treatment with the vasodilator. CONCLUSION : In young non-hypertensive eNOS-/- mice, the lack of eNOS did not affect microvascular densities in either of the muscles studied. In adult hypertensive eNOS-/- mice, we observed a lower arteriolar density, but a similar capillary density compared with controls. Hydralazine prevented hypertension and arteriolar rarefaction in adult mice, suggesting a non-NO-dependent pathway. Capillary density was not affected by hydralazine.     

Constitutive androstane receptor agonist, TCPOBOP, attenuates steatohepatitis in the methionine choline-deficient diet-fed mouse

AIM： To ascertain whether constitutive androstane receptor （CAR） activation by 1,4-bis-[2-（3,5,- dichloropyridyloxy）] benzene （TCPOBOP） modulates steatohepatitis in the methionine choline-deficient （MCD） diet-fed animal.METHODS： C57/BL6 wild-type mice were fed the MCD or standard diet for 2 wk and were treated with either the CAR agonist, TCPOBOP, or the CAR inverse agonist, androstanol.RESULTS： Expression of CYP2B10 and CYP3A11, known CAR target genes, increased 30-fold and 45-fold, respectively, in TCPOBOP-treated mice fed the MCD diet. TCPOBOP treatment reduced hepatic steatosis （44.6 ＋ 5.4% vs 30.4 ＋ 4.5%, P 〈 0.05） and serum triglyceride levels （48 ＋ 8 vs 20 ＋ 1 mg/dL, P 〈 0.05） in MCD diet- fed mice as compared with the standard diet-fed mice. This reduction in hepatic steatosis was accompanied by an increase in enzymes involved in fatty acid microsomal co-oxidation and peroxisomal p-oxidation, namely CYP4A10, LPBE, and 3-ketoacyI-CoA thiolase. The reduction in steatosis was also accompanied by a reduction in liver cell apoptosis and inflammation. In contrast, androstanol was without effect on any of the above parameters.CONCLUSION： CAR activation stimulates induction of genes involved in fatty acid oxidation, and ameliorates hepatic steatosis, apoptosis and inflammation.     

Effect of macrophage-derived apolipoprotein E on established atherosclerosis in apolipoprotein E-deficient mice

Apolipoprotein E-deficient (apoE(-/-)) mice have hyperlipidemia and develop spontaneous atherosclerosis in a time-dependent manner. Although macrophage-derived apoE has been shown to prevent the development of atherosclerosis in apoE(-/-) mice, whether it would induce regression of established atherosclerosis is unknown. To determine this, 8-week-old apoE(-/-) mice were transplanted with apoE(+/+) bone marrow. Four weeks after transplantation, when plasma cholesterol levels had reached normal levels, a group of mice (n=12) were killed and their aortic lesions were measured and used as a baseline to judge regression. Twelve and 20 weeks after transplantation, aortic lesion areas of the mice were 9340+/-2184 micrometer(2) (mean+/-SEM, n=8) and 12 211+/-1433 micrometer(2) (n=9), respectively, values not significantly different from the lesion areas of the baseline mice (12 347+/-2487 micrometer(2); n=12, P>0.05). In contrast, apoE(-/-) mice reconstituted with apoE(-/-) bone marrow developed severe atherosclerotic lesions (453 036+/-29 767 micrometer(2), n=7) 20 weeks after transplantation. These data suggest that macrophage-derived apoE was insufficient to induce significant regression of established atherosclerotic lesions in apoE(-/-) mice, although it was sufficient to eliminate hypercholesterolemia and prevent progression of aortic lesions.     

Alteration in DNA synthetic response of thymocytes from NZB mice of different ages

Thymocytes from NZB and DBA/2 mice were injected into lethally irradiated C57 B1/6 recipients. DNA synthesis in spleen and lymph node was measured as the incorporation of radioactive 5-iodo-2-deoxyuridine. The generation of cytotoxic effector cells was also studied in an in vitro cytotoxicity assay, with EL-4 lymphoma target cells. The kinetics of DNA synthesis were similar for 2- and 8-week-old DBA/2 donors and for 2-week-old NZB donors with a peak on day 4. Thymocytes from 8-week-old and 9-month-old NZB donors showed a delayed onset of DNA synthesis which was still increasing on day 6. When NZB donor thymocytes from 2- and 8-week-old mice were mixed together before injections, as few as 25% of 8-week-old cells gave a DNA synthetic response characteristic of this aged population. These results suggest an abnormal thymocyte development in NZB mice which may relate to the subsequent emergence of autoimmune disease.     

Iodine sufficiency and measurements of thyroid function in maternal hypothyroidism

OBJECTIVES: To test the hypothesis that thyroglobulin (Tg) and free T4 (FT4) concentrations more than 2SD from the control mean are not increased in pregnancy in an iodine replete area in the absence of elevated TSH concentrations. The second hypothesis to be tested was that if such abnormalities in FT4 and Tg in the absence of elevated TSH concentrations were to exist they would not be associated with lowered IQs in the progeny. DESIGN: Cross-sectional study in New England comparing TSH, Tg, antibodies to Tg and FT4 in volunteer nonpregnant women 20-40 years old with those in hypothyroid mothers and matched euthyroid control mothers. The results are contrasted with those from similar studies reported from iodine deficient areas. SUBJECTS: Sera obtained at 17 weeks gestation and stored at -20 degrees C for 8 years were retrieved and analysed from 62 mothers with subclinical hypothyroidism and 124 matched euthyroid mothers. The diagnosis of hypothyroidism was made by finding a TSH concentration > 97.7 percentiile for 25 000 consecutive pregnant women. Sera were also analysed from 53 healthy nonpregnant volunteer women aged 20-40 years. MEASUREMENTS: TSH, Tg and Tg antibodies were measured in the sera of the nonpregnant volunteers, and Tg and Tg antibodies in the sera of the pregnant women who had previously been analysed for TSH and FT4. The incidence of FT4 concentrations below the 2.3 percentile of nonpregnant laboratory controls was compared for the euthyroid and hypothyroid mothers and the laboratory normal controls. RESULTS: Thirty-one per cent of the 62 hypothyroid mothers had FT4 concentrations below the 2.3 percentile compared with only one (0.8%) of the euthyroid mothers. Mean Tg concentrations did not differ between the nonpregnant controls and the euthyroid pregnant women, 14 +/- 10 vs. 16 +/- 10 micro g/l. Tg concentration in the hypothyroid mothers was 44 +/- 61, significantly greater than for either of the euthyroid control groups, P < 0.005. Positive antibodies to Tg were found in 9% and 10% of the control groups and 57% of the hypothyroid mothers, P < 0.0005. When TSH is included as an independent variable in multiple linear and logistic regressions, FT4 and Tg no longer correlate significantly with IQs. CONCLUSIONS: The incidences of FT4 concentrations more than 2SD below the control mean and of Tg > 2SD above the control mean are significantly increased in hypothyroid mothers in iodlne-sufficient New England. However, in the absence of elevated TSH concentrations, the incidences of such abnormalities in FT4 and TG are negligible. Indeed, concentrations for FT4, Tg and Tg antibodies for nonpregnant and pregnant controls in our iodine-replete area do not differ significantly from each other or from previously reported normative concentrations with the methods used. Thus, pregnancy in New England neither increases Tg nor lowers FT4 concentrations.     

Left ventricular function and collagen content after regression of hypertensive hypertrophy

To determine whether regression of hypertensive hypertrophy through blood pressure control also involves left ventricular collagen and consecutive alterations in left ventricular diastolic and systolic function, antihypertensive treatment with the calcium channel blocker nifedipine (30 mg/kg.day) was employed in 20-week-old spontaneously hypertensive rats (n = 15) for a period of 20 weeks. Age-matched (40 weeks old) untreated (n = 13) and 20-week-old spontaneously hypertensive rats representing the state before therapy (n = 14) were used for comparison. Myocardial stiffness was described by the tangent modulus Km of the elastic stiffness-stress relation. Left ventricular collagen was determined by means of hydroxyproline (OH-proline) concentration. Myocardial working capacity of the left ventricle was measured as the peak developed systolic pressure per weight unit muscle mass and systolic peak pump function as the maximum achievable cardiac output under volume loading. After the 20-week course of nifedipine treatment, systolic aortic pressure dropped from 187 +/- 11 to 144 +/- 6 mm Hg (p less than 0.001). Regression of hypertrophy was shown by a left ventricular muscle/body weight ratio of 2.13 +/- 0.18 mg/g (p less than 0.01) in the 40-week-old nifedipine-treated hypertensive rats, whereas the ratios of the 20-week-old and 40-week-old untreated spontaneously hypertensive rats were 2.3 +/- 0.30 and 2.34 +/- 0.18 mg/g, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Induction of inducible nitric oxide synthase,argininosuccinate synthase,and GTP cyclohydrolase I in arthritic joints of human tumor necrosis factor-alpha transgenic mice

OBJECTIVE: Transgenic mice that express human tumor necrosis factor-alpha (Tg197 h-TNF-alpha) develop polyarthritis at 3 to 4 weeks of age leading to severe joint destruction at 8 to 10 weeks of age. Studies have suggested that inducible nitric oxide synthase (iNOS) activity can modulate the progression of arthritis. We investigated the induction of iNOS together with argininosuccinate synthase (AS) and GTP cyclohydrolase I (GTPCH), 2 of the rate-limiting enzymes for high output NO generation, in the Tg197 h-TNF-alpha transgenic model of arthritis. METHODS: We used 4 and 8-week-old Tg197 h-TNF-alpha transgenic mice and wild-type CBA C57B1/6 control mice to investigate the expression of iNOS with respect to that of AS, GTPCH, and 3-nitrotyrosine by quantitative RT-PCR and immunocytochemistry. Urinary NO metabolites were analyzed using a chemiluminescence assay. RESULTS: Inducible NOS, AS, and GTPCH mRNA was found in all study groups; however, only iNOS mRNA showed a clear increase in 4-week-old Tg197 h-TNF-alpha transgenics in comparison to age matched wild-type controls. Abundant iNOS protein expression was found in macrophages and vascular smooth muscle cells in hyperplastic synovium and pannus. AS expression was found in vascular endothelium and fibroblasts of the inflammatory synovium and pannus. GTPCH immunoreactivity was mostly restricted to macrophages in inflammatory synovium. Localization of 3-nitrotyrosine overlapped with that of iNOS, indicating formation of reactive nitrogen species. Consistent with the high output NO generation, there was a 5-fold increase in urinary NO metabolites in 8-week-old Tg197 h-TNF-alpha transgenic mice. CONCLUSION: We characterized the Tg197 h-TNF-alpha transgenic model of inflammatory arthritis in terms of high output NO-generating pathway, and showed that both AS and GTPCH are intimately associated with inflammatory arthritis. The concomitant induction of AS and GTPCH with that of iNOS suggests that they may be important modulators of arthritis, and that they may represent novel targets for modulation of disease activity.