罗格列酮减轻肾大部切除大鼠心肌单核细胞趋化蛋白1、转化生长因子β1的表达

目的 观察罗格列酮对肾大部切除大鼠心肌单核细胞趋化蛋白1(MCP-1)、转化生长因子β1(TGF-β1)表达的影响.方法 将大鼠随机分为4组:假手术组、肾大部切除组、肾大部切除加小剂量罗格列酮治疗组(给予罗格列酮5 mg.kg-1.d-1)和肾大部切除加三倍剂量罗格列酮治疗组(给予罗格列酮15mg·kg-1.d-1).8 w后观察大鼠血压、尿蛋白、血BUN、Scr,并用放免法测定血清血管紧张素Ⅱ(A2),用免疫组化检测心肌组织MCP-1的表达.用RT-PCR的方法测定心肌组织TGF-β1的表达.结果 与假手术组相比,肾大部切除组心肌组织MCP-1的表达明显升高(P＜0.01),肾大部切除加小剂量罗格列酮治疗组和肾大部切除加三倍剂量罗格列酮治疗组心肌组织MCP-1的表达较肾大部切除组降低,以肾大部切除加三倍剂量罗格列酮治疗组为明显(P＜0.01).与假手术组相比,肾大部切除组大鼠的心肌组织TGF-β1m RNA的表达显著升高(P＜0.01),罗格列酮治疗组大鼠的心肌组织TGF-β1 mRNA的表达较肾大部切除组有所降低(P＜0.05),三倍剂量罗格列酮治疗组更加明显(P＜0.01).结论 罗格列酮可降低肾大部切除大鼠的血压;剂量依赖性地降低尿蛋白和改善肾功能;下调血清A2,抑制心肌组织MCP-1和TGF-β1的表达,抑制心肌组织胶原纤维沉积、减轻心肌纤维化,改善其左心室病理性重构,对慢性肾衰竭大鼠的心脏起到保护作用.     

曲尼司特对糖尿病大鼠肾脏TGF-β1和SGK1表达的影响

目的探讨曲尼司特对糖尿病大鼠肾脏的保护作用及其可能的机制。方法雄性SD大鼠60只,随机均分为4组:正常对照组、模型组、低剂量及高剂量曲尼司特治疗组。后3组均一次性给予链脲佐菌素(STZ)30 mg/kg尾静脉注射建立糖尿病大鼠模型。正常对照组给予等量柠檬酸缓冲液尾静脉注射;模型组不再给药;低、高剂量曲尼司特组于造模后1 w分别给予曲尼司特100 mg·kg-1·d-1和400 mg·kg-1·d-1。造模后8 w处死大鼠,免疫组化检测肾间质组织中的TGF-β1及SGK1表达;Masson染色观察肾间质绿染面积。结果与正常大鼠相比,糖尿病模型大鼠的血糖、尿蛋白定量、肾重/体重、肌酐清除率明显升高(P<0.05);经过曲尼司特处理后,以上指标均有下降,尿蛋白定量、肾重/体重、肌酐清除率下降(P<0.05),且高剂量组与低搅量组相比,尿蛋白定量下降(P<0.05)。Masson染色可见模型组肾间质内大量胶原纤维增生,肾小球局灶性节段性硬化,而曲尼司特组上述改变均有减轻。免疫组化示TGF-β1及SGK1表达趋势一致,正常对照组均低于其他组(P<0.01),曲尼司特组低于模型组,高剂量曲尼斯特组低于低剂量组(P<0.05)。结论曲尼司特能改善糖尿病大鼠的生化指标,下调TGF-β1和SGK1表达,发挥抗纤维化的作用。     

阿托伐他汀对系膜增殖性肾炎大鼠平滑肌肌动蛋白和转化生长因子β1表达的影响

目的观察阿托伐他汀对系膜增殖性肾炎大鼠24h尿蛋白、肾组织平滑肌肌动蛋白(α-SMA)和转化生长因子β1(TGF-β1)表达的影响,探讨其肾脏保护作用的机制。方法采用抗胸腺细胞血清诱发的系膜增殖性肾炎大鼠模型,将SD大鼠随机分为正常对照组、肾炎模型组、小剂量阿托伐他汀治疗组(8mg/kg·d)和大剂量阿托伐他汀治疗组(16mg/kg·d,n=8),每组块大鼠治疗12d后,检测各组大鼠血总胆固醇、甘油三酯、血肌酐(Scr)和24h尿蛋白,以及肾组织α-SMA和TGF-β1的表达。结果阿托伐他治疗组大鼠24h尿蛋白、肾小球α-SMA及肾组织TGF-β1mRNA的表达明显下降,肾组织病理改变明显改善,与模型组相比有显著性差异(P<0·05),且呈剂量依赖关系。其中肾炎模型组尿蛋白(30·34±0·62)mg/d,阿托伐他汀小剂量治疗组(21·17±0·79)mg/d,大剂量治疗组(9·77±0·54)mg/d。同时,各组血脂水平无明显差异(P>0·05)。结论阿托伐他汀可显著改善系膜增殖性肾炎大鼠肾脏病变,抑制系膜细胞的增生,减少系膜基质的蓄积,其机制可能与抑制TGF-β1的表达有关。     

螺内酯抑制大鼠单侧输尿管梗阻后肾间质纤维化

目的探讨螺内酯对单侧输尿管梗阻(UUO)大鼠肾间质纤维化的影响。方法2004-12～2005-03对UUO大鼠给予螺内酯20mg·kg-1·d-1及50mg·kg-1·d-1灌胃,观察第14天血清钾、钠、肌酐、血压的变化及肾间质纤维化程度、转化生长因子-β1(TGF-β1)、α-平滑肌肌动蛋白(α-SMA),纤维连接蛋白(FN)的表达。结果与UUO组相比,两治疗组血清钾、钠、肌酐、血压差异均无显著性(P>0.05),肾小管间质纤维化程度,TGF-β1、α-SMA、FN的表达与UUO组差异有显著性(P<0.05),两治疗组之间差异无显著性(P>0.05)。结论螺内酯可通过抑制细胞因子释放和肾小管-间质细胞的表型转化等非血压依赖机制延缓肾间质纤维化。     

中剂量双重阻断肾素血管紧张素系统对糖尿病肾病大鼠肾小管间质转化生长因子-β1、结缔组织生长因子表达的影响

目的 观察中剂量双重阻断肾素血管紧张素系统对糖尿病肾病(DN)大鼠肾小管间质转化生长因子(TGF)-β1、结缔组织生长因子(CTGF)表达的影响.结果 将链脲佐菌素(STZ)诱导的DN大鼠模型随机分为对照组(A组)、贝那普利组(B组)、贝那普利联合氯沙坦组(C组),B组给予贝那普利10 mg·kg-1·d-1灌胃,C组给予贝那普利5 mg·kg-1·d-1、氯沙坦10 mg·kg-1·d-1灌胃,8 w后免疫组化观察各组肾小管间质TGF-β1、CTGF表达,RT-PCR测定TGF-β1、CTGF mRNA表达.结果 B组、C组大鼠小管间质TGF-β1、CTGF表达及mRNA表达较A组均明显下调(P＜0.01),同时C组与B组比较其表达表达也显著下调(P＜0.05).结论 中剂量贝那普利与氯沙坦联合阻断肾素血管紧张素系统,比单用贝那普利能更有效下调DN大鼠肾小管间质TGF-β1、CTGF的表达.     

来氟米特联合贝那普利对糖尿病肾病大鼠肾组织TGF-β1和CTGF表达的影响

目的探讨联合应用来氟米特和贝那普利对糖尿病肾病(DN)大鼠肾组织中转化生子因子(TGF)-β1和结缔组织生长因子(CTGF)表达的影响及其可能机制。方法分为正常对照组(NC)、DN模型组(DN)、贝那普利组、来氟米特组和联合用药组。腹腔注射链脲佐菌素(STZ,65 mg/kg)建立糖尿病(DM)模型,正常对照组腹腔注射相应剂量的枸橼酸缓冲液。成模后贝那普利组给予贝那普利(10 mg·kg-1·d-1)灌胃,来氟米特组给予来氟米特(10 mg·kg-1·d-1)灌胃,联合用药组给予来氟米特(10 mg·kg-1·d-1)和贝那普利(10 mg·kg-1·d-1)灌胃,NC和DN模型组给予蒸馏水灌胃。在实验第4、8、12周末测量体重,收集24 h尿液,检测24 h尿蛋白排泄量(24 h UPE)和尿肌酐(Ucr);第4、8周末眼眶后静脉采血,第12周末乙醚麻醉后心脏采血,测空腹血糖(Glu)、血肌酐(Scr)、计算内生肌酐清除率(Ccr),摘取双肾,称量左肾重量,计算肾重指数,采用免疫组化法观察各组大鼠肾组织中TGF-β1和CTGF的表达水平,同时观察肾组织病理变化。结果 DN模型组和各用药组组大鼠24 h UPE显著增加(P<0.01);8 w末起联合用药组较DN模型组明显减少(P<0.05)。TGF-β1和CTGF在DN组大鼠肾小球内、肾小管上皮细胞及间质内均强烈表达(P<0.01),各用药组表达较DN组减少,联合用药组表达较贝那普利组和来氟米特组更显著减少(P<0.05)。结论来氟米特联合贝那普利抗肾脏纤维化而保护肾脏、延缓DN进展,其作用机制可能是通过下调TGF-βl、CTGF的表达而实现的,其联合治疗效果明显优于单独用贝那普利或来氟米特。     

减阻剂改善自发性高血压大鼠主动脉重塑

目的减阻剂(DRP)是一种可以减少流体阻力、增加流体剪切应力的线性高分子化合物,本实验观察静脉应用DRP对自发性高血压大鼠(SHR)主动脉重塑的影响。方法 24只8周龄雄性SHR随机分为3组:SHR+生理盐水组(SHR+NS组)、SHR+10 mg/L DRP组、SHR+20 mg/L DRP组,隔日给予静脉注射NS或不同剂量的DRP;8只年龄匹配的雄性Wistar大鼠(WR)作为对照组(WR+NS组),给予静脉注射NS。实验开始前及每20天记录大鼠体重、尾动脉收缩压、心率。60天后大鼠麻醉后心脏取血,酶联免疫吸附测定法检测大鼠血清内皮素(ET)水平。处死大鼠,分离大鼠升主动脉,石蜡包埋,HE染色观察主动脉形态结构,免疫组织化学法检测主动脉内皮素1(ET-1)表达。结果 SHR各组间体重、心率无显著差异。SHR+20 mg/L DRP组血压较SHR+NS组明显降低(P0.05),而SHR+10 mg/L DRP组与SHR+NS组血压无统计学差异。与SHR+NS组相比,SHR+10mg/L DRP组及SHR+20 mg/L DRP组血清ET水平显著降低,差异具有统计学意义。主动脉HE染色显示,与WR+NS组相比,SHR+NS组主动脉中膜厚度明显增厚(P0.05);静脉应用DRP后,与SHR+NS组相比,SHR+10mg/L DRP组、SHR+20 mg/L DRP组主动脉中膜厚度均显著降低(P0.05);SHR+10 mg/L DRP组、SHR+20mg/L DRP组与WR+NS组之间主动脉中膜厚度无统计学差异。主动脉免疫组织化学染色显示,ET-1在血管内皮及中层平滑肌均有表达,SHR大鼠主动脉表达明显高于WR大鼠;经静脉应用DRP后,SHR+10 mg/L DRP组、SHR+20 mg/L DRP组主动脉ET-1较SHR+NS组显著降低,SHR+10 mg/L DRP组与SHR+20 mg/L DRP组之间主动脉ET-1无显著差异。结论静脉应用DRP可改善SHR主动脉重塑,其机制可能与DRP通过增加主动脉内血液剪切应力抑制了ET-1表达有关,减阻剂可能为治疗高血压引起的主动脉重塑提供新的思路。     

盐酸埃他卡林的降压作用及对高血压血管重构的影响

目的在自发性高血压大鼠(spontaneously hypertensive rat, SHR)上,评价盐酸埃他卡林(Iptakalim hydrochloride,Ipt)对高血压血管重构的实验治疗学作用.方法 21只12周龄SHR随机分为3组Ipt 3 mg/kg治疗组,赖诺普利(lisinopril, Lis)12 mg/kg治疗组和空白对照组.另设同月龄正常血压Wistar大鼠为正常对照组.大鼠ig Ipt、Lis或蒸馏水10 ml/kg,每日1次,连续4周,观察药物对高血压血管重构的影响.结果实验期4周内,SHR对照组血压和心率持续性进行性增高.其主动脉中层壁显著增厚,中层壁厚与内径的比值(M/L)也显著增大;肠系膜动脉的中层壁显著增厚,内径显著变小,二者的比值显著增大,表明高血压时动脉的结构发生了重构.Ipt能有效控制SHR的血压,降压效果确切,且可抑制SHR心率加快的趋势;Ipt治疗可阻止肠系膜动脉和主动脉的结构重构.相同实验条件下,Lis也均能有效控制SHR的血压,降压效果确切,对心率无明显影响;Lis治疗也可阻止肠系膜动脉和主动脉的结构重构.结论 Ipt能有效地控制SHR的血压,可以阻止高血压血管结构重构.     

罗格列酮减轻大鼠残肾单核细胞趋化蛋白1、转化生长因子β_1的表达

研究背景罗格列酮是过氧化物酶增殖体活化受体γ(PPAR-γ)激动剂,可调节反应基因转录和炎性因子表达。已有研究发现 PPAR-γ激动剂可防止肾功能恶化,但在慢性肾衰竭中,罗格列酮是否通过对单核细胞趋化蛋白1(MCP-1)、转化生长因子β_1(TGF-β_1)表达的影响起肾脏保护作用尚不明了。目的观察罗格列酮对肾大部切除大鼠残肾 MCP-1、TGF-β_1表达的影响。方法将大鼠随机分为4组,每组8只:假手术组、肾大部切除组(NX 组)、肾大部切除加小剂量罗格列酮治疗组(XL 组,罗格列酮5 mg/(kg·d))和肾大部切除加大剂量罗格列酮治疗组(DL 组,罗格列酮15 mg/(kg·d))。8周后观察大鼠血压、尿蛋白、BUN、SCr 和肾脏病理改变,用免疫组化检测肾组织 MCP-1的表达。用 RT-PCR 的方法测定肾组织 TGF-β_1的表达。结果 1)罗格列酮能降低肾大部切除大鼠血压,与 NX 组比较差异有非常显著意义(P<0.01),且呈剂量—效应依赖关系。2)罗格列酮能降低大鼠尿蛋白、BUN、SCr,与 NX 组比有显著差异(P<0.01)。24 h 尿蛋白定量:假手术组(2.8±1.6)g 比 NX ...     

阿托伐他汀对系膜增殖性肾炎大鼠平滑肌肌动蛋白和转化生长因子β1表达的影响

目的观察阿托伐他汀对系膜增殖性肾炎大鼠24 h尿蛋白、肾组织平滑肌肌动蛋白(α-SMA)和转化生长因子β1(TGF-β1)表达的影响,探讨其肾脏保护作用的机制.方法采用抗胸腺细胞血清诱发的系膜增殖性肾炎大鼠模型,将SD大鼠随机分为正常对照组、肾炎模型组、小剂量阿托伐他汀治疗组(8 mg/kg·d)和大剂量阿托伐他汀治疗组(16 mg/kg·d, n=8),每组块大鼠治疗12 d后,检测各组大鼠血总胆固醇、甘油三酯、血肌酐(Scr)和24 h尿蛋白, 以及肾组织α-SMA和TGF-β1的表达.结果阿托伐他治疗组大鼠24 h尿蛋白、肾小球α-SMA及肾组织TGF-β1mRNA的表达明显下降,肾组织病理改变明显改善,与模型组相比有显著性差异(P<0.05),且呈剂量依赖关系.其中肾炎模型组尿蛋白(30.34±0.62)mg/d,阿托伐他汀小剂量治疗组(21.17±0.79)mg/d,大剂量治疗组(9.77±0.54)mg/d.同时,各组血脂水平无明显差异(P>0.05).结论阿托伐他汀可显著改善系膜增殖性肾炎大鼠肾脏病变,抑制系膜细胞的增生,减少系膜基质的蓄积,其机制可能与抑制TGF-β1的表达有关.     

Combination therapy with telmisartan and spironolactone alleviates L-NAME exacerbated nephrosclerosis with an increase in PPAR-gamma and decrease in TGF-beta(1)

To investigate whether the receptor blockades of angiotensin II type 1 and aldosterone receptors can prevent renal tissue injury in relation to the renal tissue mRNA levels of peroxisome proliferation-activated receptors-gamma (PPAR-gamma) and transforming growth factor-beta (1) (TGF-beta(1)) in spontaneously hypertensive rats (SHR) given N(G)-nitro-L-arginine methyl ester (L-NAME), which is considered a model of malignant hypertension. This study was performed in 5 groups of 17-week-old male SHR treated for 3 weeks as follows: group 1, control; group 2, L-NAME (50 mg/L in drinking); group 3, L-NAME plus aldosterone antagonist, spironolactone (SPRL, 100 mg/kg/day); group 4, L-NAME plus angiotensin II type 1 receptor blocker, telmisartan (TELM, 3 mg/kg/day); group 5, L-NAME plus combination therapy (COMB) with low-dose TELM (1 mg/kg/day) and SPRL (100 mg/kg/day). Urinary protein excretion and the glomerular injury score were significantly reduced in the SPRL, TELM, and COMB groups as compared with the L-NAME group, while significant blood pressure reduction was observed only in the TELM group. In the TELM and COMB groups, the perivascular cell infiltration and fibrosis area were significantly reduced together with the PPAR-gamma mRNA increase and TGF- beta(1) mRNA decrease. The urinary excretion of nitric oxides was significantly recovered and the wall to lumen ratio of the interlobular artery was significantly reduced only in the COMB group compared with the L-NAME group. Combined administration of 1 mg/kg/day telmisartan and 100 mg/kg/day spironolactone is thought to be effective in alleviating hypertensive renal injuries independently of blood pressure changes. The anti-inflammatory and antifibrotic effects due to PPAR-gamma activation and TGF-beta(1) inhibition may participate in the renoprotection of this combination therapy.     

Neutralization of transforming growth factor-beta attenuates hypertension and prevents renal injury in uremic rats

OBJECTIVE: We investigate the role of transforming growth factor-beta (TGF-beta) in hypertension and renal failure progression in uremic rats, and whether it modulates the endothelin (ET) system. DESIGN: Following renal mass reduction, uremic rats (Nx) received the pan-specific TGF-beta neutralizing antibody 1D11 (0.5 mg/kg, three times/week), the isotype control antibody 13C4 or the AT1 antagonist losartan (10 mg/kg per day) for 6 weeks. RESULTS: Before treatment, the blood pressure was higher in Nx rats and increased further over time in Nx+13C4 rats. At the end of the study, Nx+13C4 rats exhibited increased serum creatinine, proteinuria and renal expression and excretion of TGF-beta1 and ET-1. ET-1 concentrations were greater in vascular and renal tissues, whereas the ETB receptor expression was reduced. Renal injuries were comprised of blood vessel hypertrophy, glomerular sclerosis, tubular atrophy and interstitial fibrosis, which was associated with increased alpha-smooth muscle actin expression. Treatment of uremic rats with the 1D11 antibody attenuated the increase in blood pressure and the decline in renal function. Losartan normalized the blood pressure and significantly attenuated the increase in serum creatinine and proteinuria. However, both treatments prevented renal TGF-beta1 and ET-1 overexpression, and prevented all renal histological injuries. The 1D11 antibody only improved ETB receptor expression. CONCLUSIONS: Neutralization of TGF-beta attenuates hypertension and renal failure progression in uremic animals, in part, by preventing renal injury processes. These effects may be related to the modulation of the ET system, preventing renal ET-1 overproduction and the reduction of ETB receptor expression. Our data also suggest that TGF-beta1 is involved, at least in part, in the pathological effects related to angiotensin II in chronic renal failure.     

Blood pressure-independent effect of angiotensin AT1 receptor blockade on renal endothelin-1 production in hypertensive uremic rats

OBJECTIVE: We recently reported that treatment of uremic rats with reduced renal mass with the angiotensin II (Ang II) subtype 1 receptor (AT1) antagonist losartan reduces endothelin-1 (ET-1) levels in blood vessels and in glomeruli. Although this suggests an important role for Ang II in the modulation of ET-1 production, the concomitant decrease in blood pressure may also be involved. The present study was designed to investigate whether the modulation of ET-1 production in uremic rats is related to tissue-specific effects of AT1 receptor blockade or to the antihypertensive effect of losartan. DESIGN: One week after renal mass reduction, uremic rats were treated with the conventional triple therapy (TRx) [reserpine (5 mg/l), hydralazine (80 mg/l) and hydrochlorothiazide (25 mg/l)] or losartan (20 mg/kg per day) for 6 weeks. Immunoreactive-ET-1 (ir-ET-1) levels in plasma and urine, as well as in vascular and renal tissues were measured by a specific radioimmunoassay after sample extraction and purification. RESULTS: Before treatment, systolic blood pressure was significantly higher in uremic animals compared to sham-operated controls (165+/-4 versus 123+/-2 mmHg, respectively; P < 0.01). Treatment with the TRx or with losartan normalized systolic blood pressure in uremic rats, whereas it was further increased in untreated uremic animals. At week 6, serum creatinine, proteinuria and urinary ET-1 and transforming growth factor-beta1 (TGF-beta1) excretion, as well as vascular and glomerular ET-1 content were increased in uremic rats compared to the controls (P < 0.01). Treatment of uremic rats with the TRx or with losartan reduced ET-1 content in the thoracic aorta and the mesenteric arterial bed (P < 0.01). However, losartan, but not the TRx, significantly attenuated the rise of serum creatinine, proteinuria and urinary ET-1 and TGF-beta1 excretion, as well as ET-1 content in glomeruli of uremic rats. Compared with the controls, renal preproET-1 mRNA expression was also significantly higher in uremic rats. Treatment of uremic rats with losartan prevented renal preproET-1 mRNA overexpression, indicating that changes in glomerular ET-1 content and urinary ET-1 excretion were related to modulation of renal ET-1 production. CONCLUSIONS: These findings indicate that the effect of losartan on ET-1 production in peripheral blood vessels may be mediated, in part, by the reduction of blood pressure. In contrast, the reduction of renal ET-1 production is mediated by tissue-specific effects of AT1 receptor blockade, and may contribute to the renal protective effects of losartan.     

Chronic endopeptidase inhibition in DOCA-salt hypertension: mechanism of cardiovascular protection

These studies examined the interactions of neutral endopeptidase (NEP), endothelin-1 (ET-1), and nitric oxide (NO) in deoxycorticosterone acetate (DOCA)-induced hypertension. Male Sprague-Dawley rats (n = 35) were uninephrectomized (UNx) or uninephrectomized and treated with DOCA (25 mg pellet implanted subcutaneously). Candoxatril (30 mg/kg day(-1)), a NEP inhibitor, was given orally for 3 weeks in UNx or DOCA rats. Sham nephrectomized rats (SHAM) served as controls. Except SHAM, all other groups received 1% NaCl in drinking water ad libitum. Measurements were taken of systolic blood pressure (SBP), left ventricle (LV), and aortic weight (AW), plasma ET-1, and urinary excretion of nitrite and Na+. Whole body vascular hypertrophy and morphometric analysis of histological sections of the heart were also determined. In DOCA rats, SBP increased from 113 +/- 5 to 170 +/- 5 mmHg without significant changes in body weight (BW). Candoxatril reduced the increase in SBP to 135 +/- 9 mmHg (P < 0.05), abolished the increased LV wall thickness (P < 0.05), and increased the reduced LV lumen diameter (P < 0.05) in DOCA-salt rats. Candoxatril also reduced plasma ET-1 by 88 +/- 9% and 89 +/- 17% (P < 0.05) in UNx and DOCA rats, respectively, and elicited increases in urinary excretion of nitrite. These effects were accompanied by a marked increase in urinary excretion of Na+ (U(Na)V) (P < 0.05) and a blunting of the proteinuria (32 +/- 5%; P < 0.05) in DOCA rats. We conclude that endopeptidase inhibition in DOCA-salt hypertension reduced the increase in blood pressure and the attendant tissue hypertrophy and renal injury. These effects suggest a correlation between endopeptidase-related reduction in ET-1 production and protection in DOCA-salt hypertension.     

Urinary TGF-beta1 reduction related to a decrease of systolic blood pressure in patients with type 2 diabetes and clinical diabetic nephropathy

With the aim to determine the influence of reducing systolic blood pressure in urinary TGF-beta1 of type 2 diabetes (DM2) with diabetic nephropathy (DN), 21 subjects with type 2 diabetes and proteinuria >500 mg/24 h were studied. Amlodipine and ramipril were added to their previous antihypertensive treatment for 12 weeks. Urinary TGF-beta1 (UTGF-beta1) was determined at 0, 4, 8 and 12 weeks. Plasma TGF-beta1 was determined at 0 and 12 weeks. Subjects whose mean systolic blood pressure (SBP) during treatment were under 140 mmHg were grouped as the better SBP controlled group (n = 11) and those with SBP equal to or greater than 140 mHg were grouped in a moderate SBP controlled group (n = 10). Compared to baseline, mean log UTGF-beta1 at 4, 8 and 12 weeks decreased (-0.22 +/- 0.15 pg/mg; p = 0.04) in better SBP controlled group but not in the moderate SBP controlled group (-0.12 +/- 0.08 pg/mg, p = 0.82). Mean SBP correlated with UTGF-beta1 (r = 0.458, p = 0.0357), and this effect was independent of HbA1c (p = 0.042). By controlling SBP in DM2 subjects with DN we might decrease UTGF-beta1. We propose that reduction of UTGF-beta1 is due to a decrease in renal TGF-beta1 production.     

Renal and systemic effects of endothelin-1 in diabetic-hypertensive rats

The Cohen-Rosenthal Diabetic Hypertensive rat (CRDH) is a unique animal model in which genetic hypertension and diabetes developed after crossbreeding of Cohen diabetic rats sensitive substrain (CDR) and spontaneously hypertensive rats (SHR). The present study examined: 1) The acute effects of ET-1 on the systemic and renal hemodynamics in CRDH rats, CDR, and SHR; 2) The expression of ET-1 and its receptors in the renal tissue of CRDH rats. Intravenous injection of ET-1 (1.0 nmol/kg) into anesthetized SHR rats resulted in a significant immediate depressor response (mean arterial pressure (MAP) decreased from 165 ± 3 to 124 ± 12 mmHg, p < 0.0001) followed by a minor hypertensive phase (MAP increased to 170 ± 2 mmHg). Simultaneously, the administration of ET-1 caused a significant decrease in renal blood flow (RBF) from 5.8 ± 0.9 ml/min to 3.2 ± 0.5 ml/min (p = 0.026). These responses were blunted in CRDH rats and CDR. Analysis of intra-renal blood flow by laser-Doppler in CRDH rats revealed that ET-1 injection caused a decrease in cortical blood flow (Δ = -12 ± 2.9%). However, in contrast to its well-known renal medullary vasodilatory effect, ET-1 produced a significant decline in the medulla blood flow (Δ = -17.5 ± 3.4%) (p = 0.0125). These findings suggest that CDR and CRDH rats have reduced sensitivity to vascular and renal action of ET-1. Furthermore, in the CRDH rats, the expected ET-1-induced medullary vasodilatation was abolished and even reversed into prolonged vasoconstriction.     

Short- and long-term effects of ferulic acid on blood pressure in spontaneously hypertensive rats

Ferulic acid (4-hydroxy-3-methoxycinnamic acid) is a phenolic compound contained in rice bran and other plants. The effect of ferulic acid on blood pressure (BP) was investigated in spontaneously hypertensive rats (SHR). After oral administration of ferulic acid (1 to 100 mg/kg) to SHR, systolic blood pressure (SBP) significantly decreased in a dose-dependent manner. When oral ferulic acid (50 mg/kg) was administered to SHR, BP was lowest at 1 h and returned to basal levels at 6 h. There was a significant correlation between SHR plasma ferulic acid and changes in the SBP of the tail artery, suggesting that absorbed ferulic acid reduces BP. When 7-week-old SHR were given 10 and 50 mg/kg/d of ferulic acid for 6 weeks, increases in BP were significantly attenuated compared to SHR on the control diet. Intravenous injection of ferulic acid dose dependently reduced carotid arterial pressure in anesthetized SHR. Furthermore, the depressor effect of intravenous ferulic acid (1 mg/kg) was significantly attenuated by pretreatment of SHR with the nitric oxide (NO) synthase inhibitor N^G-nitro-l-arginine methyl ester (L-NAME; 3 mg/kg, administered intravenously). These data suggest that the hypotensive effect of ferulic acid in SHR is associated with NO-mediated vasodilation.     

氯沙坦对自发性高血压大鼠左心室结构改变的实验研究

目的 :探讨氯沙坦 (Los)对自发性高血压大鼠 (SHR)左心室结构的影响。方法 :6周龄Los治疗组 (SHRlos)管饲法给予Los3 0mg kg天。治疗 17周后 ,观察 3组大鼠动脉收缩压 (SBP)、左心室 (LV)壁的厚度、左心室重量 体重 (LVW BW)以及左心室结构的变化 ;血浆放免法测肾素活性和AngⅡ含量。结果 :1 SBP :治疗结束后 ,SHRlos组血压 10 9 15± 11 3 1mmHg( 1mmHg =0 .13 3kPa) ,与对照组 (SHR)血压167 4± 13 0 1mmHg相比明显下降 (P <0 0 1)。 2 SHRlos组的LVW BW、LV壁厚度与SHR组相比明显减少 (P <0 0 1)。SHRlos心肌的超微结构与正常对照组 (WKY)相似。 3 血浆肾素活性在WKY组和SHR组之间无明显差异 (P >0 0 5 )。SHRlos组肾素活性及AngⅡ水平分别高于SHR组 (P <0 0 5 ,P <0 0 1)。结论 :Los能有效地降低SHR的血压 ,具有预防高血压LVH的作用。     

Mechanisms of big endothelin-1-induced diuresis and natriuresis : role of ET(B) receptors

Endothelin-1 (ET-1) at high concentrations has marked antidiuretic and antinatriuretic activities, whereas its precursor, big endothelin-1 (big ET-1), has surprisingly potent diuretic and natriuretic actions. The mechanisms underlying the excretory effects of big ET-1 have not been fully elucidated. To explore these mechanisms, we examined the effects of a highly selective ET(B) antagonist (A-192621.1), a calcium channel blocker (verapamil), a nitric oxide synthase inhibitor (N-nitro-L-arginine methyl ester [L-NAME]), and a cyclooxygenase inhibitor (indomethacin) on the systemic and renal actions of big ET-1 in anesthetized rats. An intravenous bolus injection of incremental doses of big ET-1 (0.3, 1. 0, and 3.0 nmol/kg) produced a significant hypertensive effect that was dose dependent and prolonged (from 113+/-7 mm Hg to a maximum of 148+/-6 mm Hg). The administration of big ET-1 induced marked diuretic and natriuretic responses (urinary flow rate increased from 8.5+/-1 to 110+/-14 microL/min, and fractional excretion of sodium increased from 0.38+/-0.13% to 7.51+/-1.24%). Glomerular filtration rate and renal plasma flow significantly decreased only at the highest dose of big ET-1. Pretreatment with A-192621.1 (3 mg/kg plus 3 mg. kg(-1). h(-1)) significantly abolished the diuretic (17+/-5 microL/min to a maximum of 19+/-3 microL/min) and natriuretic (0. 29+/-0.1% to a maximum of 1.93+/-0.37%) responses induced by big ET-1. Moreover, A-192621.1 potentiated the decline in glomerular filtration rate and renal plasma flow and the increase in mean arterial blood pressure produced by the low doses of big ET-1. Similar to A-192621.1, pretreatment with a nitric oxide synthase inhibitor (L-NAME, 10 mg/kg plus 5 mg. kg(-1). h(-1)) significantly and comparably reduced the diuretic and natriuretic actions of big ET-1 and augmented the hypoperfusion/hypofiltration and systemic vasoconstriction induced by high doses of the peptide. Pretreatment with verapamil (2 mg. kg(-1). h(-1)) slightly inhibited the diuretic/natriuretic effects of the high-dose big ET-1 and completely prevented the increase in mean arterial blood pressure provoked by the peptide. Unlike verapamil and L-NAME, only indomethacin administration was associated with significant natriuretic/diuretic responses and did not influence the pressor effect and renal actions of big ET-1. Taken together, these results suggest that big ET-1-induced diuretic and natriuretic responses are mediated mainly by stimulation of nitric oxide production coupled to ET(B) receptor subtype activation.     

知母百合与厄贝沙坦联合运用对高血压大鼠血压和血流动力学的影响

目的观察中药方剂知母百合与厄贝沙坦联合运用对高血压大鼠的血压和血流动力学的影响。方法采用自发性高血压大鼠(SHR)和肾血管狭窄性高血压大鼠(RVHR)模型,将高血压大鼠随机分成4组:对照组(CMC溶剂,n=10)、厄贝组(厄贝沙坦40mg/kg,n=10)、联合组(厄贝沙坦40mg/kg加知母百合浓缩药粉1250mg/kg,n=10)及中药组(知母百合浓缩药粉1250mg/kg,n=10)。动态观察灌胃给药后以下指标的变化:清醒状态下的SHR和RVHR的收缩压(SBP)、舒张压(DBP)、脉压(PP)及收缩压变异率(SBPV)变化;SHR的左心室收缩末期内压(LVESP)、左心室舒张末期内压(LVEDP)、心室内压最大上升速率( dp/dtmax)、心室内压最大下降速率(-dp/dtmax)的变化。结果在SHR和RVHR急性清醒测压中,厄贝组及联合组的SBP及DBP较给药前均明显降低,下降幅度可达20mmHg～28mmHg(1mmHg=0.133kPa,P<0.05);与对照组相比,两组SBP及DBP降低幅度为19mmHg～28mmHg(P<0.05);联合组与厄贝组相比,SBP和DBP降低幅度为6mmHg～9mmHg(P<0.05)。不论给药前后或者与对照组相比,中药组的血压参数无统计学意义(P>0.05)。在SHR的血流动力学实验中,厄贝组及联合组的SBP及DBP较对照组明显下降(15mmHg～24mmHg,P<0.05);各组之间的LVESP、LVEDP、 dp/dtmax、-dp/dtmax无统计学意义(P>0.05)。结论常规剂量的知母百合本身没有降压作用,对大鼠心脏的血流动力学也没有明显影响,但可协同厄贝沙坦的降压作用(幅度6mmHg～9mmHg)。