Endothelin-1, an important mitogen of smooth muscle cells of spontaneously hypertensive rats

OBJECTIVE: To study the features of vascular smooth muscle cell (VSMC) proliferation induced by endothelin-1 (ET-1). METHODS: VSMCs of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats were cultured and treated with ET-1. Basic fibroblast growth factor (bFGF) gene expression was measured using both Northern blot and an enzyme-linked immunoassay. RESULTS: ET-1 resulted in an increase in bFGF transcripts at 8 - 24 h; bFGF levels were significantly higher in VSMCs treated with ET-1 than in those not treated. However, VSMCs growth responses in SHR and WKY were different. Smooth muscle cells of SHR were hyper-responsive to ET-1. Maximal bFGF mRNA levels were elevated 3.5-fold at 4 h of stimulation in WKY and 8-fold at 8h in SHR4. Moreover, the proliferation of VSMCs induced by ET-1 was inhibited by antisense phosphorothioate oligodeoxynucleotides (10 micromol/L AS-bFGF) but not sense bFGF oligomers at the same concentrations, being reduced by 80% in SHR and 40% in WKY vs control, respectively. Furthermore, the effect of AS-bFGF oligomers on SHR SMC proliferation is significantly greater than on WKY SMC proliferation. CONCLUSION: ET-1 may be required for exaggerated vascular growth responses in SHR and bFGF may be involved.

Influence of Valsartan on myocardial apoptosis in spontaneously hypertensive rats

OBJECTIVE: To explore the pathogenic changes of myocardial apoptosis in heart hypertrophy during hypertension and evaluate the anti-apoptosis effect of Valsartan. METHODS: Thirty spontaneously hypertensive rats (SHRs) were divided into two groups: 15 treated with Valsartan (20 mg x kg(-1) x d(-1)) (SHR + Valsartan group), the others with placebo (SHR + placebo group), with 15 normal Wistar rats as control. Systolic blood pressure was measured by the tail-cuff method. The observation period was from 8 to 16 weeks of age. Cardiac apoptosis was evaluated by a Terminal Deoxynucleotidyl Transferase-Mediated dUTP-biotin Nick End Labeling (TUNEL) assay. RESULTS: Mean blood pressure values were 127 +/- 2 mm Hg in controls, 163 +/- 6 mm Hg in the SHR + Valsartan group and 193 +/- 7 mm Hg in the SHR + placebo group at 16 weeks of age, whereas the blood pressure in 8-week-old SHR and Wistar rats were 175 +/- 3 mm Hg and 125 +/- 5 mm Hg, respectively. The ratio of the heart weight over body weight declined in Wistar (3.07 +/- 0.03 mg/g) and SHR + Valsartan groups (3.22 +/- 0.19 mg/g) compared with the SHR + placebo group (4.02 +/- 0.31 mg/g) (P

Endothelin receptor antagonist combined with a calcium channel blocker attenuates renal injury in spontaneous hypertensive rats with diabetes

OBJECTIVE: To investigate the effects of the mixed endothelin receptor antagonist, bosentan, combined with the long-acting calcium channel blocker, amlodipine, compared to the angiotensin-converting enzyme inhibitor, cilazapril, on the progressive renal injury in spontaneous hypertensive rats (SHR) with diabetes. METHODS: Diabetic hypertensive rats (SHR-DM) were induced by streptozotozin injected in male SHR (7-week-old),and divided into an untreated and three treated groups: 1) cilazapril treated group; 2) bosentan+amlodipine treated group; and 3) amlodipine treated group. Wistar Kyoto rats (WKY) and SHR rats served as normotensive and hypertensive control, respectively. The mean arterial blood pressure, renal function, endothelin and angiotensin II levels as well as the protein expression of renal extracellular matrix components and transforming growth factor (TGF)-beta1 were determined at the end of the 4th week. RESULTS: Mean arterial blood pressure significantly increased in SHR and SHR-DM rats compared to WKY rats. All the therapies reduced the blood pressure to normal levels. However, the enhanced urinary protein excretion, the decreased creatinine clearance as well as the increased plasma and intrarenal endothelin and angiotens in II levels were found in the untreated SHR-DM and prevented by treatment with bosentan+amlodipine and cilazapril. Similarly, these two kinds of therapies in SHR-DM abolished the overexpression of renal TGF-beta1 by Western blot analysis and reduced the accumulation of collagen type IV, laminin and fibronectin proteins by an immunochemical approach. Amlodipine monotherapy had no detectable effects on the above parameters. CONCLUSION: Bosentan combined with amlodipine can offer similar renoprotective effects on that of cilazapril and may be a potent therapy to attenuate renal injury by reducing renal protein levels of TGF-beta1 in diabetes with a hypertensive state.

Ventricular remodeling by Scutellarein treatment in spontaneously hypertensive rats

OBJECTIVE: To observe reversal of ventricular remodeling by the protein kinase C inhibitor Scutellarein in spontaneously hypertensive rats (SHRs). METHODS: Twelve SHRs were randomly divided into two groups. Scutellarein and saline (10 mg x kg(-1) x d(-1)) were given by intraperitoneal injection to two groups of rats separately. Systolic blood pressure (SBP) and ventricular weight index (LVW/BW, RVW/BW) were measured. A polarization microscope and an image analyzer system (IAS) were used to observe changes in cardiovascular structure and to count the content of cardiac muscle interstitial collagen. RESULTS: The pathologic changes in the left ventricle in the Scutellarein group rats (SHR(D)) improved to varying degrees, including hypertrophy of the cardiac muscle and collagen volume fraction. CONCLUSION: Scutellarein can reverse ventricular remodeling, improve myocardial stiffness and protect heart cardiac muscle.

Five novel monoclonal antibodies to thymic epithelial cell surface antigens in rats

OBJECTIVE: To establish monoclonal antibodies (mAbs) against thymic epithelial cells and study the function of epithelial cells during T-cell differentiation in the thymus. METHODS: Hybridomas secreting mAbs against thymic epithelial cells were derived by immunization of Balb/c mice with two thymic epithelial cell lines, TaD3 and FTE. The distribution of antigens recognized by these mAbs was detected by immunochemical staining and cytofluorographic analysis, and the molecular weight of the antigens by immunoblotting. RESULTS: Five specific monoclonal antibodies (mAb) were obtained. On the basis of their distribution in the thymus determined by immunochemical staining, mAb RE-4D8 was regarded as clusters of thymic epithelium staining (CTES) type IIA: mAb RE-12B2, which showed a unique distribution pattern only in the medulla, was CTES type V: mAb RE-5C6 was CTES type IV: mAb RE-6D6 might be CTES type IIB: and mAb RE-1D4 was classified as type V. The molecular weight (MW) of antigen RE-4D8, RE-6D6 and RE-12B2 were 120 kDa, 220 kDa and 35 kDa, respectively. Antigen RE-1D4 is a novel marker of cortical epithelium, several established thymic epithelial cell lines were classified and their original intrathymic locations were determined by these mAbs. Thymic cell lines, TuD3 and FTE were cortical phenotypes whereas TaD3 had a medullar phenotype. CONCLUSIONS: These mAbs clearly demonstrate the heterogeneity of the thymic epithelium; they could detect antigens not only in the cytoplasm but also on the surface of thymic epithelial cells. Our data suggest that these newly established mAbs may help elucidate the interaction between thymocytes and epithelial cells during T cell maturation.

六味地黄丸对OLETF鼠胰岛素抵抗的影响

目的观察六味地黄丸对自发性2型糖尿病大鼠模型OLETF鼠胰岛素抵抗的影响。方法自发性2型糖尿病大鼠OLETF鼠40只,随机分为六味地黄丸干预组和对照组;LETO鼠10只作为正常对照组。干预组从8周龄起以六味地黄丸2.4mg/(kg.d)灌胃给药,其余两组以等量清水灌胃。定期OGTT试验,监测各组大鼠摄食及体重增长情况,每周称量大鼠体重和摄食量。于8,32和40周龄时分批宰杀大鼠。检测血浆胰岛素。结果对照组和干预组OLETF鼠摄食量显著高于LETO组(P<0.01)。对照组和干预组OLETF鼠体重从第6周开始显著高于LETO组(P<0.05)。干预组血浆胰岛素显著低于对照组(P<0.05),与LETO组相比差异无显著性(P<0.05)。结论六味地黄丸能够显著降低OLETF鼠血糖升高程度,延缓高血糖的出现;六味地黄丸能够显著降低血浆胰岛素。

高脂血症对OLETF大鼠肾小管上皮细胞尿酸盐阴离子交换器表达的影响

目的:探讨自发代谢综合征及2型糖尿病动物模型(OLETF大鼠)在高脂血症阶段肾小管上皮细胞尿酸盐阴离子交换器(URAT1)的表达。方法:选择雄性4周龄OLETF大鼠10只为OLETF组,同系4周龄LETO大鼠(非糖尿病)10只为LETO组,基础饮食至11周龄,记录7周龄和11周龄大鼠体重、体长,检测甘油三酯(TG)、总胆固醇(TC)、尿酸(UA)、肌酐、尿素氮、高密度脂蛋白,采用荧光定量RT-PCR方法检测URAT1在肾皮质中的表达量。结果:大鼠11周龄时,OLETF组TG、TC较LETO组显著增高,均P<0.05;UA较LETO组升高,但P>0.05;URAT1 mRNA的表达水平为2.17,较LETO组(1.00)明显升高,P<0.05。结论:OLETF大鼠在高脂血症阶段,随着尿酸的升高,URAT1 mRNA的表达明显升高。可能通过上调URAT1的表达,来调节体内尿酸的排泄。脂代谢紊乱和高尿酸血症可能通过该纽带密切相关联。

利拉鲁肽对糖耐量异常OLETF大鼠胰岛白细胞介素-1β表达的影响

目的观察利拉鲁肽对糖耐量异常大鼠胰岛炎症因子白细胞介素-1β(IL-1β)和凋亡基因caspase3表达的影响。方法 12周龄糖耐量异常OLETF大鼠分为生理盐水组和不同剂量利拉鲁肽干预组(50、100、200μg/kg),8只LETO作为正常对照组。实验12周结束时,所有大鼠均检测糖耐量试验空腹及服糖后30 min胰岛素,并检测胰岛IL-1β和caspase3 mRNA和蛋白水平。结果利拉鲁肽干预的糖耐量异常大鼠和生理盐水干预组相比,胰岛IL-1β和caspase3表达显著降低,血糖、胰岛β细胞功能及早期胰岛素分泌指数明显改善。结论利拉鲁肽可能通过抑制胰岛IL-1β炎症因子表达,从而改善胰岛功能及糖代谢,延缓或阻止糖尿病发生发展。

胰升糖素样多肽-1对OLETF大鼠胰腺的保护作用

目的:观察胰升糖素样多肽-1(glucagon like peptide-1,GLP-1)对OLETF(O tsuka Long-Evans Tokush im a fat-ty)大鼠血糖和糖耐量的影响,及其对胰腺B细胞的保护作用。方法:将12周雄性OLETF大鼠分为GLP-1治疗和未治疗组,并以同种系非糖尿病LETO(Long-Evans Tokush im a O tsuka)大鼠为正常对照。于12,14及20周时,对所有大鼠进行口服葡萄糖耐量试验(OGTT)试验,饲养至20周时处死。对胰腺病理切片分别进行HE染色、胰岛素染色、增殖细胞核抗原染色(proliferation cell nuc lear antigen,PCNA)及凋亡细胞染色,测量胰岛B细胞的增殖率和凋亡率。用电镜观察胰岛内细胞超微结构。结果:(1)14及20周OLETF大鼠GLP-1治疗组血糖曲线下面积低于OLETF未治疗组,分别为(29.93±3.15vs.34.99±4.30,P<0.01)和(38.37±3.18vs.42.38±2.37,P<0.01)。(2)14及20周OLETF大鼠GLP-1治疗组胰岛素曲线下面积高于OLETF未治疗组,分别为(10.86±1.56vs.9.07±1.28,P<0.01)和(13.00±1.50vs.10.35±0.86,P<0.01)。(3)20周龄GLP-1治疗组OLETF大鼠胰岛内胰岛素含量以及胰岛中B细胞数量增加,B细胞超微结构改善。胰岛B细胞的增殖率增加(48.9±39.6vs.39.6±9.3,P<0.05),凋亡率下降(24.8±4.2vs.30.8±5.8,P<0.01)。结论:GLP-1能够通过促进胰岛B细胞增殖抑制其凋亡,增加胰岛B细胞数目,改善B细胞内分泌颗粒的形态,从而改善2型糖尿病大鼠的糖耐量。

脂联素在OLETF大鼠脂肪组织中的表达及意义

目的观察自发2型糖尿病动物模型OLETF大鼠脂肪组织脂联素mRNA表达的变化。方法选择4周龄的雄性OLETF大鼠20只,LETO大鼠10只作为对照组,饲养28周后,行口服葡萄糖耐量试验(OGTT);取空腹血清测甘油三酯、游离脂肪酸、胆固醇和血浆胰岛素水平;取大网膜脂肪组织,RT-PCR检测脂联素mRNA表达。结果OGTT试验结果显示,OLETF组大鼠负荷后0.5h和1h血糖明显高于LETO大鼠(P<0.05);OLETF组大鼠血清甘油三酯和血浆胰岛素水平显著高于LETO组(P<0.05)。OLETF组大鼠脂肪组织脂联素mRNA表达量明显低于LETO组(P<0.05)。结论OLETF大鼠脂肪组织脂联素mRNA表达水平明显降低。

利拉鲁肽对IGT-OLETF大鼠血清糖基化终末产物及炎症指标的影响

目的观察利拉鲁肽对糖耐量异常(IGT)OLETF大鼠血清糖基化终末产物(AGEs)、炎症指标及糖代谢的影响。方法实验共分为5组。12周龄IGT-OLETF大鼠32只,随机均分为4组,分别予生理盐水(OLETF-saline组)和不同剂量利拉鲁肽(50、100、200μg/kg)腹腔注射,2次/d;另取8只LETO大鼠注射生理盐水作为正常对照组。12周后测定各组大鼠血清AGEs、炎症因子及糖代谢指标水平。结果干预前IGT-OLETF大鼠空腹血糖(FPG)、餐后2h血糖(2hPG)、空腹胰岛素均较LETO大鼠升高;给予不同剂量利拉鲁肽干预12周后,FPG、2hPG、空腹胰岛素、AGEs及炎症指标肿瘤坏死因子-α(TNF-α)、血清超敏C反应蛋白(Hs-CRP)、白细胞介素-6(IL-6)水平均较OLETF-saline组降低(P<0.05)。干预实验结束后,OLETF-saline组87.5%的OLETF大鼠发展成糖尿病,利拉鲁肽干预组大鼠均未发生糖尿病。结论利拉鲁肽能有效改善IGT-OLETF大鼠的糖耐量异常及胰岛素抵抗,同时降低大鼠血清AGEs和炎症指标,提示利拉鲁肽可能通过降低非酶糖化和炎症水平而发挥抗炎作用,延缓IGT向糖尿病进展。

替米沙坦对高脂饲养OLETF大鼠心肌重构及PPARγ表达的影响

目的探讨替米沙坦对高脂饲养的OLETF大鼠心肌重构及过氧化物酶体增殖物激活受体γ(PPARγ)表达的影响。方法 4周龄雄性OLETF大鼠28只,高脂喂养。22周龄时称质量后随机分为替米沙坦组[O-T组,5mg/(kg·d),n=10],吡格列酮组[O-P组,10 mg/(kg·d),n=8]及无干预对照组[O-C组,等体积生理盐水,n=10],连续给药26周;选取性别、周龄匹配的正常非糖尿病LETO大鼠为空白对照(LETO组,n=12)。分别于22周龄和48周龄时行口服葡萄糖耐量试验(OGTT)检测大鼠2型糖尿病(T2DM)和糖耐量异常(IGT)发病情况。48周龄时给药结束后每组随机抽取5只大鼠行高胰岛素-正糖钳夹实验,计算60~120 min的葡萄糖输注速度(GIR60-120)。实验结束时处死动物,分离心脏,称量心脏质量(HW)和体质量(BW),以HW/BW判定心肌肥厚情况。ELISA法测定血清PPARγ、肿瘤坏死因子(TNF)-α、白细胞介素(IL)-6水平,放射免疫法测定血清脂联素水平。Real-time PCR检测心肌组织中PPARγ1、PPARγ2及IL-6 m RNA表达水平,Western blot法检测心肌组织中PPARγ、脂联素、IL-6及核因子(NF)-κB蛋白表达水平。光镜和电镜下分别观察各组大鼠心肌常规病理改变(HE染色、Masson染色、PAS染色)和超微结构改变。结果 22周龄时,各组大鼠均未发生T2DM及IGT。48周龄时O-C组7只发展为T2DM,2只IGT;O-T组1只T2DM,3只IGT;其他2组未见T2DM和IGT。48周龄时,O-P组、O-T组GIR60-120及HW/BW均明显低于O-C组(P<0.05),同时O-T组大鼠收缩压(SBP)、舒张压(DBP)较其他3组明显下降(P<0.05)。与O-C组相比,O-T组血清IL-6、TNF-α水平下降,脂联素和PPARγ水平则明显升高(P<0.05);O-P及O-T组间上述指标差异均无统计学意义。Real-time PCR及Westen blot结果显示,与O-C组相比,O-T组PPARγ1 m RNA表达升高、IL-6表达降低,O-P组及O-T组PPARγ、脂联素的蛋白表达均明显升高,而NF-κB及IL-6蛋白表达下降(均P<0.05)。光镜和电镜下可见O-C组心肌细胞受损严重,纤维排列紊乱,胞浆溶解,心肌间质中出现大量胶原纤维增生,糖原和脂褐素沉积,肌原纤维断裂和核周扩张,心肌线粒体明显受损甚至溶解,O-P组和O-T组心肌纤维排列整齐,无明显糖原沉积,心肌超微结构损害明显减轻。结论小剂量替米沙坦可上调高脂饲养OLETF大鼠循环及心肌组织中PPARγ的表达,减轻心肌纤维化,延缓心肌重构。

六味地黄丸对OLETF鼠糖尿病发病的干预研究

目的通过观察六味地黄丸对自发性2型糖尿病OLETF大鼠脂肪组织脂联素的影响,探讨六味地黄丸对2型糖尿病发病的干预作用。方法自发性2型糖尿病大鼠OLETF鼠40只,随机分为六味地黄丸干预组和对照组,LETO鼠10只作为正常对照组。干预组从8周龄起以六味地黄丸2.4mg·kg-1·d-1灌胃给药,其余两组以等量清水灌胃。定期口服葡萄糖耐量试验。于8、32和40周龄时分批宰杀大鼠。采用半定量逆转录PCR方法,检测脂肪组织脂联素mRNA表达水平。结果六味地黄丸能够显著降低OLETF鼠血糖升高程度,延缓高血糖的出现。与对照组相比,干预组脂肪组织脂联素mRNA表达量明显增加。干预组糖尿病的发病率显著低于同时期对照组(P<0.01)。LETO组无IGT或糖尿病发生。结论六味地黄丸能明显增加OLETF鼠脂肪组织脂联素表达水平;六味地黄丸可显著降低2型糖尿病动物模型OLETF鼠糖尿病的发病率,有效预防糖尿病的发生。

六味地黄丸对OLETF大鼠胰腺凋亡相关基因bcl-2和Bax表达的影响

目的:探讨六味地黄丸对自发性2型糖尿病大鼠胰腺组织凋亡相关基因bcl-2和Bax表达的影响。方法:OLETF大鼠(自发性2型糖尿病)40只,随机分为六味地黄丸治疗组和模型组,每组20只;另同系LETO大鼠(非糖尿病)10只作为正常对照组。六味地黄丸治疗组于大鼠8周龄起,用六味地黄丸按2.4 g.kg-1.d-1灌胃,余组用等量蒸馏水灌胃。每周记录大鼠体质量;采用口服葡萄糖耐量试验监测血糖;定期处死大鼠,分离胰腺并称重;采用逆转录-聚合酶链反应检测bcl-2和Bax在胰腺组织中的表达。结果:大鼠40周龄时,六味地黄丸治疗组bcl-2 mRNA的表达水平为(1.25±0.07),较模型组(1.01±0.16)明显增高(P<0.01);Bax mRNA的表达水平为(0.57±0.11),较模型组(1.18±0.28)有明显降低(P<0.01)。六味地黄丸治疗组的胰腺/体重比,较模型组增高,但差异无统计学意义。六味地黄丸治疗组的糖负荷能力明显高于模型组(P<0.05或P<0.01)。结论:六味地黄丸在转录水平可上调bcl-2 mRNA的表达,下调Bax mRNA的表达,可能具有抗细胞凋亡的作用。

血脂变化对OLETF糖尿病大鼠肾小球细胞外基质成分含量的影响

目的 采用 OL ETF大鼠来观察血脂变化对 2型糖尿病鼠肾小球细胞外基质含量的影响。方法 实验动物分为三组即正常对照组、糖尿病组和非诺贝特治疗的糖尿病组。非诺贝特 2 0 mg· kg- 1 · d- 1 灌胃 2 2周。用免疫组化的方法检测肾小球细胞外基质成分含量的变化。结果 糖尿病组血清总胆固醇、甘油三酯、极低密度脂蛋白和高密度脂蛋白水平明显高于正常对照 (P<0 .0 5 ) ,同时细胞外基质成分 ( 型胶原、层粘连蛋白、纤维连接蛋白 )含量亦较正常对照组增加 (三者 P<0 .0 1) ,降脂治疗后肾脏细胞外基质积聚明显减少 (与糖尿病未治疗组比 P<0 .0 5 )。结论 高脂血症可能与糖尿病肾小球硬化的发生有关 ,降脂治疗能够减缓肾脏的损害从而起到保护肾脏的作用。

OLETF大鼠胰岛素抵抗及相关因素分析

目的 探讨自发持续高血糖动物模型雄性OLETF(otsukalong evanstokushimafatty)大鼠的胰岛素抵抗状态以及各相关因素。方法 选择 14周OLETF大鼠 10只 ,LETO大鼠 10只作为对照。记录 2 4h大鼠进食量。在禁食 10～ 14h后 ,测定大鼠的体重 ,采血测定空腹血脂谱 ,行口服葡萄糖耐量试验 (OGTT)。大鼠处死后 ,测定腹内脂肪 ,取大鼠股四头肌测定脂肪酸谱。留尿 ,测定尿酮兰蛋白 (U CP)、尿白蛋白 (U Alb)和肌酐(Cr) ,计算U CP/Cr和U Alb/Cr。采用正常血糖高胰岛素钳夹技术 ,评价其胰岛素抵抗状态。结果 ①OLETF大鼠进食量明显高于LETO大鼠 ;②OLEFT大鼠体重明显高于LETO大鼠 ,腹内脂肪、大网膜脂肪和肾周脂肪也高于LETO大鼠 ;③OLETF大鼠三酰甘油、胆固醇均高于LETO大鼠 ;④OLETF大鼠U CP/Cr高于LETO大鼠 ;⑤除空腹血糖外 ,OLETF大鼠葡萄糖负荷后各点血糖均较高 ;⑥OLETF大鼠的葡萄糖输注率 (GIR)明显降低 ;⑦OLETF大鼠和LETO大鼠的多不饱和脂肪酸 (PUFA)相似 ,但OLETF大鼠以n 6PUFA含量较高 ,而LETO大鼠以n 3PUFA含量较高。结论 14周的OLETF大鼠已存在胰岛素抵抗 ,体重和腹内脂肪重量增加 ,同时存在三酰甘油和胆固醇的增高及肌肉组织磷脂中n 6PUFA/n 3PUFA含量的改变。

PVG大鼠生化标记基因的测定

目的 对PVG大鼠进行生化标记基因的测定。方法 依据国家标准GB/T 14927.1—2008《实验动物近交系小鼠、大鼠生化标记检测法》测定,随机抽取4只PVG大鼠,取(肺、肾、小肠、睾丸)组织器官进行样品制备,用醋酸纤维薄膜电泳法检测11个生化位点(Hbb、Cs1、Alp1、Akp1、Esl、Es3、Es4、Es6、Es8、Es9和Esl0)。结果 PVG大鼠11个位点的基因型分别是Hbb为b型,Cs1为b型,Alp1为b型,Akp1为a型,Esl为a型,Es3为d型,Es4为b型,Es6为b型,Es8为b型,Es9为a型和Esl0为a型,且均为纯合。结论 PVG大鼠遗传生化标记结果符合近交系特征。

Effects of electroacupuncture at Taichong(LR 3) and Baihui(DU 20)on cardiac hypertrophy in rats with spontaneous hypertension

OBJECTIVE: To investigate the effects of electroacupuncture(EA) at Taichong(LR 3) and Baihui(DU 20)on myocardial hypertrophy in spontaneously hypertensive rats(SHRs).METHODS: Thirty-six SHRs were randomly assigned to model, EA, and Losartan groups, with twelve rats per group. Twelve Wistar Kyoto rats were selected as the normal control group. Systolic blood pressure(SBP) and cardiac function were measured in all rats.Expression levels of factors associated with the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin(PI3K/Akt/mTOR) pathway were evaluated by Western blotting and real-time PCR.Pathological changes of the heart tissue were observed by hematoxylin-eosin staining.RESULTS: After treatment, enhanced SBP was significantly decreased in the EA and Losartan groups compared with the model group(P < 0.01). Echocardiographic and morphological analyses revealed that enhanced end-diastolic interventricular septal thickness and left ventricular posterior wall thickness, as well as ratio of left ventricular weight to body weight were markedly diminished in the EA and Losartan groups(P < 0.01 or P < 0.05), while reduced left ventricular end-diastolic dimension and left ventricular ejection fraction were significantly ameliorated(P < 0.01). Real-time PCR and western blotting analyses showed that the expression levels of PI3K,Akt, and mT OR in SHRs were significantly up-regulated by EA and Losartan(P < 0.01), while the expression levels of PTEN and ANP were down-regulated(P < 0.01).CONCLUSION: EA at Taichong(LR 3) and Baihui(DU20) inhibited the development of cardiac hypertrophy and improved the cardiac function in SHRs, possibly through regulation of the PI3K/Akt/mTOR signalling pathway.

OLETF糖尿病大鼠心肌光镜与透射电镜病理改变的观察

目的使用光镜与透射电镜,观察OLETF糖尿病大鼠在糖尿病病程中晚期的心肌病理改变。方法以7只OLETF糖尿病大鼠作为实验动物模型,做OGTT试验诊断并了解糖尿病病程。另以7只LETO大鼠为对照。鼠龄58周时检测血浆血脂、胰岛素、C-肽水平,评估胰岛功能及脂代谢状况。股动脉插管测量血压、颈动脉逆行插管入左心室测量左室内压以评估心功能。石蜡切片HE、PAS、VG染色观察心肌光镜组织结构。两组各取3只大鼠超薄切片透射电镜观察心肌超微结构,测量心肌壁毛细血管基膜厚度并进行比较。结果OG-TT试验显示34周后80%OLETF糖尿病大鼠已发生糖尿病,鼠龄58周时三酰甘油、胆固醇较对照组明显增加(P<0.05)。左心室压下降速率(-dp/dt)低于对照组(P<0.05)。OLETF糖尿病大鼠HE染色显示心肌细胞肥大,肌纤维收缩呈波浪状;PAS,VG染色显示心肌间质胶原纤维增多。超薄切片透射电镜观察显示心肌细胞挛缩、肌原纤维收缩带形成,心肌间质胶原沉积,毛细血管基膜增厚。OLETF糖尿病大鼠的基膜厚度为(64.33±4.38)nm,较LETO对照组大鼠(46.09±3.62)nm明显增厚(P<0.001)。结论58周龄OLETF糖尿病大鼠的心肌病理改变为心肌细胞挛缩、心肌间质胶原沉积和毛细血管基膜增厚,并与左心室舒张功能减退同时存在。

六味地黄丸对OLETF鼠胰腺形态学改变的影响

目的:研究六味地黄丸对自发性2型糖尿病鼠(otsukalong-evanstokushimafattyrats,OLETF鼠)胰腺形态学改变的影响。方法:OLETF鼠40只,随机分为六味地黄丸干预组和对照组,LETO(long-evanstokushimaotsuka)鼠10只作为正常对照组。干预组从8周龄起以六味地黄丸2.4g/(kg·d)灌胃给药,其余两组以等量蒸馏水灌胃。每周监测体重,定期OGTT试验检测血糖,胰腺切片HE染色观察组织学改变。结果:OLETF鼠体重和血糖显著高于LETO鼠。随病程进展,OLETF鼠对照组胰岛早期表现为肥大增生,晚期破坏、纤维化程度明显高于LETO鼠。干预组胰岛结构保存明显好于对照组,且干预组负荷后血糖显著低于对照组。结论:六味地黄丸能有效地保护OLETF鼠胰腺的组织形态结构并改善其糖代谢能力。