Ventricular remodeling and intervention with losartan following rabbit chronic hibernating myocardium

Objectives To explore the changes of myocyte and the interstitial collagen in a model of chronic hibernating myocardium (CHM) in rabbits, and to determine whether these alterations affect the cardiac function, and to further observe the effects of losartan on ventricular remodeling. Methods A left anterior descending (LAD) coronary artery stenosis was created and maintained for 4 weeks to create a CHM model in rabbits. Thirty-six rabbits were assigned to the following three groups(12 rabbits per group): CHM for 4 weeks(CHM group), low-dose of losartan intervention group for 4 weeks(LTl group, 10 mg·kg-1·d-1), high-dose of losartan intervention group for 4 weeks (LT2 group, 30 mg·kg-1·d-1); and 12 sham-operated rabbits served as controls (SO group). A microscopic imaging system (Image-Pro Plus, Olympus) was used to assess the Interstitial collagen volume fraction (ICVF) in myocardial sections with picrosirius-red staining, and a polarized light microscopy to qualitatively analysis the changes in the type and the proportion of collagen fibers, to semi-quantitatively score the proportion of collagen I to collagen III(PI/III). The expression of MMP-2, 9 and TIMP-2 was assessed by immunohistochemistry and western bloting. The myocyte apoptosis rate (Rapo) was calculated with TUNEL-staining. And echocardiography was performed to measure left ventricular end-systolic and end-diastolic diameter (LVESD, LVEED), and left ventricular short-axis fraction shortening (LVFS) and ejection fraction (LVEF). Results The animal model of CHM was induced successfully in 36 out of 39-rabbits and maintained for 28 days. Compared with the sham group, ICVF) was significantly increased (P<0.01) in CHM group; compared with CHM group, ICVF was significantly decreased (P<0.01,each) in LTl group and LT2 group, and the change were more remarkable in LT2 group, compared to LTl group(P<0.05). Compared with sham group, PI/IH was significantly increased (P < 0.01) in CHM group; compared with CHM group, PI/III was significantly decreasedin the losartan intervention groups (P<0.01,each), and the change was more remarkable in LT2 group compared to LTl group (P<0.05). Compared with sham group, the expression of MMP-2 and MMP-9 were greatly increased (P<0.01) in CHM group, while TIMP-2 were greatly decreased(P< 0.01); compared with CHM group, the expression of MMP-2 and MMP-9 were significantly decreased (P<0.01,each) .while TIMP-2 were significantly increased (P<0.01,each) in the losartan intervention groups, and the change was more remarkable in LT2 group than in LT1 group (.P<0.05). Compared with sham group, myocyte Rapo was markedly increased (P<0.01) in CHM group; compared with CHM group, myocyte Rapo was significantly decreased (P<0.01,each) in the losartan intervention groups, and the change was more remarkable in LT2 group than in LT1 group (P<0.05). Compared with sham group, LVEF and LVFS were significantly reduced in CHM group (P <0.01), compared with CHM group, LVEF and LVFS were higher (P<0.01,each) in the losartan intervention groups ,and the changes were more remarkable in LT2 group than in LTl group (P<0.05). Conclusions CHM underwent interstitial collagen proliferation and myocyte apoptosis, leading to ventricular remodeling and ventricular functional impairment, Losartan intervention reduces myocyte apoptosis and interstitial collagen proliferation, and improve ventricular function.     

Effect of Electroacupuncture Stimulation on mRNA Expression of Angiotensinogen,Angiotensin Ⅱ Type 1 Receptor,Endothelin-1,and Endothelin A Receptor in Spontaneously Hypertensive Rat Aorta

Objective: To observe the effect of electroacupuncture(EA) stimulation on the expressions of angiotensinogen(AGT), angiotensin Ⅱ type 1 receptor(AT1R), endothelin-1(ET1), and endothelin A receptor(ETAR) m RNA in spontaneously hypertensive rat(SHR) aorta. Methods: Eighteen male SHRs were randomly divided into three groups, an SHR group, an SHR Baihui(DU 20) and Zusanli(ST 36) acupoint(SHR-AP) group, and an SHR non-acupoint(SHR-NAP) group, with 6 rats in each group. Six Wistar rats were used as a control. Rats in the SHR-AP group were stimulated by DU 20 and ST 36 acupoints, both of which were connected with EA. EA was handled one time every Monday, Wednesday and Friday, for total 24 times(8 weeks). SHRNAP rats were acupointed at a 15°angle flat into 0.5 cm to two points, which were 1 and 2 cm from rail tip separately. EA parameters were the same as the SHR-AP rats. SHR control rats and Wistar rats were fixed without EA. Real-time quantitative polymerase chain reaction(PCR) was used to measure AGT, AT1 R, ET1, and ETAR m RNA expression in rat aorta. Results: EA stimulation significantly reduced rat aorta vascular AGT, ET1, ETAR and AT1 R m RNA expressions in the SHR-AP and SHR-NAP groups(P0.01). Among these four genes, AT1 R m RNA expression was significantly lower in the SHR-AP than in the SHR-NAP group(P0.01). Conclusion: EA could reduce the AT1 R m RNA expression in SHR-AP rat aorta, indicating a potential mechanism for the hypotensive effects of EA.     

Role of angiotensin Ⅱ and angiotensin Ⅱ receptors in vascular smooth muscle cell migration in vitro

ObjectiveTo determine the biotic effects of angiotensin Ⅱ (Ang Ⅱ) on the migration of rat smooth muscle cells (VSMCs) and investigate the mechanisms involved in the development of vascular injury. Methods VSMCs isolated from aortic media of Wistar rats and cultured by the modified explant method were adopted. In the presence and absence of Ang Ⅱ, the expression of Ang Ⅱ receptor (ATR) and reorganization of the actin cytoskeleton and focal adhesion of VSMCs were studied by an immunocytochemistry technique and fluorocytochemistry technique. Migration assays were performed with a modified Boyden’s chamber. The effects of AT(1)R antagonist (CV- 11974), AT2R antagonist (PD123319) on the aforementioned target were studied. Results VSMCs migration was stimulated by adding Ang Ⅱ. The dynamic reorganization of actin cytoskeleton and focal adhesions may be an important mechanism by which Ang Ⅱ facilitates VSMCs motility. The expression of AT(1)R in VSMCs could be upregulated initially after treatment with Ang Ⅱ, then decreased gradually. The expression of AT(1)R was downregulated by AT(1)R antagonists. The effect of Ang Ⅱ on VSMCs migration was mediated by AT(1)R, while AT2R had no significant effect. Conclusions The dynamic reorganization of focal adhesions and the actin cytoskeleton is required for Ang Ⅱ- induced VSMCs migration. This effect is mediated by AT(1)R.     

Association of angiotensin Ⅱ type 1 receptor gene polymorphism with essential hypertension

Objective To determine whether the polymorphism A1166C in the angiotensin Ⅱ type 1 receptor (AT1R) gene is associated with essential hypertension.Methods A case-control study was carried out using 125 hypertensive and 103 normotensive subjects. The A→C variant at position 1166 (A1166C) of t he AT1R gene was identified by polymerase chain reaction (PCR) and PCR/ restriction fragment length polymorphism (PCR/RFLP) analysis. The digestion products were separated on 2% agarose gels and visualized with ethid ium bromide under ultraviolet ray.Results The differences in C1166 allele frequency and in the AC genotype dist ribution of the AT1R gene between the hypertensive and normotensive groups were statistically significant (C allele: 0.092 vs 0.034, χ(2) =6.1 86, P&lt;0.05; AC genotype: 0.184 vs 0.068, χ(2) =6.654, P&lt;0.05).Conclusion The AC genotype is associated with essential hypertension, and the C a llele may be a marker for predisposition to hypertension in Chinese H an population.     

Effects of angiotensin Ⅱ receptor antagonist on expression of collagen Ⅲ, collagen Ⅴ, and transforming growth factor β1 in the airway walls of sensitized rats

Background Repeated attacks of bronchial asthma lead to different degrees of airway remodeling, the mechanism of which is not yet clear. Some evidences indicate that it is related to the excessive expression of some growth promotion factors. Angiotensin Ⅱ is a polypeptide that may be involved in airway remodeling. To evaluate its role in airway remodeling in asthma, we observed the effects of an angiotensin Ⅱ type 1 receptor antagonist (valsartan) on the expression of collagen Ⅲ, collagen Ⅴ, and transforming growth factor β1 (TGF-β1) mRNA and protein in the airway walls of sensitized rats.Methods Forty Wistar rats were randomly divided into 5 groups: control group, sensitized group, and valsartan groups 1, 2, and 3. The rats in the sensitized group and in valsartan groups 1, 2, and 3 were sensitized and challenged with ovalbumin. Rats in control group were sensitized and challenged with 0.9% NaCl. Rats from valsartan groups 1, 2, and 3 were drenched with valsartan (10 μg, 20 μg, or 30 μg, respectively) at the time of the ovalbumin challenges. The expression of collagen Ⅲ, collagen Ⅴ, and TGF-β1 protein were detected using immunohistochemical method in combination with image analysis methods. The expression of TGF-β1 mRNA was detected by in situ hybridization. Results The expression in the airways of collagen Ⅲ and collagen Ⅴ was significantly higher in rats from the sensitized group (7.73±0.81, 1.34±0.28) and from valsartan groups 1, 2, and 3 (5.73±0.64, 1.13±0.15; 4.96±0.51, 0.98±0.08; 4.43±0.35, 0.93±0.06, respectively) than those in the control group (2.65±0.38, 0.67±0.08, P&lt;0.05). In addition, collagen levels were significantly lower in valsartan groups 1, 2, and 3 than those from the sensitized group (P&lt;0.05). The expression of TGF-β1 mRNA and protein in the airways was significantly higher in rats from the sensitized group (20.49%±3.46%, 29.73%±3.25%) and from valsartan groups 1, 2, and 3 (16.47%±1.94%, 19.41%±1.87%; 14.38%±1.58%, 18.29%±1.43%; 12.96%±1.73%, 18.63%±1.11%, respectively) than that from the control group (7.84%±1.61%, 5.63%±1.07%, P&lt;0.05). TGF-β1 mRNA and protein levels were significantly lower in valsartan groups 1, 2, and 3 than that in the sensitized group (P&lt;0.05). Conclusions Angiotensin Ⅱ receptor antagonist valsartan can suppress synthesis of collagen Ⅲ and collagen Ⅴ by downregulating TGF-β1 mRNA and protein expression. Valsartan can decrease airway remodeling and could play a role in asthma therapy.     

POLYMORPHISM OF ANGIOTENSIN I TYPE 1 RECEPTOR GENE IN ELDERLY PATIENTS WITH ESSENTIAL HYPERTENSION

Objective To detect the A/C1165 polymorphism of angiotensin Ⅱ type Ⅰ receptor (AT1-R)gene in essential hypertensive elderly. Methods The A/C1166 polymorphism of AT1-R gene was assessed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in a case-control study of 87 essential hypertensive elders (EH) and 55 normolensive elders (NT). Results The genotype frequencies of AA, AC, CC were 0 .805 , 0.161, 0 .034 in EH group and 0 .927 ,0 .073 ,0 .000 in NT group respectively. The frequency of C61166 allele was higher in EH group (0.115) than in NT group (0 .036 )(P<0 .05 ). Conclusion The resultsindicate that A/C1166 polymorphism of AT1-R gene may be associated with essential hypertension in elderly.     

Antioxidant Mechanism of Xiaojin Pill(小金丸) for Treatment of Peyronie's Disease in Rats Based on Matrix Metalloproteinases

Objective: To evaluate the effects of Xiaojin Pill(小金丸) in the treatment of Peyronie's disease(PD) in a rat model. Methods: Twenty-four male Sprague-Dawley rats were randomly divided into four groups with 6 in each: sham operation, PD model, vehicle control and Xiaojin Pill groups. The rats in the sham operation group received penile tunica albsginea(TA) injection with 50 μL vehicle, while the rats in the other 3 groups received 50 μL penile TA injection of 50 μg transforming growth factor(TGF)-β1. Forty-two days after the injection, rats in the vehicle control and Xiaojin Pill groups received 0.5 mL water and Xiaojin Pill solution(107 mg/kg of body weight), respectively by gavage for 28 days, while those in the sham operation and PD model groups did not receive any intervention. After intervention, the expressions of matrix metalloproteinase 2/9(MMP2/9), nitric oxidesynthase(NOS), superoxide dismutase(SOD) and malondialdehyde(MDA) were measured. Results: Rats in the PD model and vehicle control groups presented obvious fibrosis in corpus cavernosum(CC) and demonstrated a significantly increased expressions of MMP2 and MMP9 in the CC compared with the sham operation group(all P0.01). In contrast, the expressions of MMP2 and MMP9 in the Xiaojin Pill group were significantly down-regulated(both P0.01). In addition, the levels of NOS and MDA in CC were significantly increased while the activity of SOD was decreased in the PD model and vehicle control groups compared with the sham operation group(al P0.01). After Xiaojin Pil treatment, the levels of MDA, NOS and SOD appeared to be corrected(al P0.01). Conclusions: Xiaojin Pill could reduce fibrosis in the CC by decreasing the expressions of MMPs, NOS and MDA, and by increasing the activity of SOD. Therefore, Xiaojin Pill might be a therapeutic option for PD.     

Effects of Qindan Capsule (芩丹胶囊) on blood pressure, endothelin, calcitonin gene-related peptide and angiotensin-II in spontaneous hypertensive rats

Objective： To observe the hypotensive effects of Qindan Capsule （芩丹胶囊, QC） on spontaneous hypertensive rats （SHR） and its effect on the contents of endothelin （ET）, calcitonin gene-related peptide （CGRP） and angiotensin-Ⅱ （Ang-Ⅱ ） in plasma and vascular tissues, and to investigate the possible mechanism of QC in lowering blood pressure. Methods： Forty SHRs were divided into 5 groups： the high dosage QC group [QCHD, 750 mg/（kg.d） ], the low dosage QC group [QCLD, 150 mg/（kgd） ], the Niuhuang Jiangya Pill group [牛黄降压丸,, NJP, 200 mg/（kg.d）], the Captopril group [ 15 mg/（kgd）]and the model group, 8 in each group. Meanwhile, a normal control group consisting of 8 Wistar-Kyoto （WKY） rats was set up also. All the rats were administered with medicine level of ET, CGRP and Ang-Ⅱ in plasma and Ang-Ⅱ rats after 12 weeks of treatment. Results： The leve through gastrogavage. Systolic blood pressure （SBP）, in tissues of mesenteric artery were detected in all the of SBP after treatment in the QCHD group was lower than that in the model group （ P〈0.01 ）, but with no significant difference as compared with that in the Captopril group and the NJP group （P〉0.05）. After treatment, the plasma level of ET was lower and CGRP higher than those in the model group （both P〈0.05）, and also higher than those in the NJP and Captopril group （both P〈0.05）. As for the content of Ang- Ⅱ , in mesenteric arterial tissues, it was lower in the QCHD group than that in the model group （ P〈0.05）, but in plasma, it showed no significant difference between the two groups （P〉0.05）. Conclusion： QC has a satisfactory hypotensive action on SHR rats, and its mechanism may be associated with the regulation on plasma vasoactive peptide and regional renin-angiotensin system.     

卡托普利和缬沙坦对大鼠心肌梗死后胶原网络重塑的干预研究

目的研究卡托普利和缬沙坦对心肌梗死（MI）后胶原网络（cardiac collagennet—work,CCN）重塑的作用及作用机制。方法SD大鼠29只,建立心肌梗死模型,随机分为3组,分别为单纯心肌梗死组（MI）、卡托普利组（Cap）和缬沙坦组（Val）,另设假手术组（s）不结扎冠状动脉。观察大鼠心肌羟脯氨酸含量（HC）;采用RT-PCR方法检测心肌营养素-1（CT-1）mRNA和糖蛋白gpl30基因（gp130）mRNA的表达。结果（1）与S组相比,MI组、Cap组和Val组心肌组织HC明显增加（P〈0．01）,差异有统计学意义;与MI组相比,Cap组和Val组非梗死区（NIZ）心肌组织HC均明显降低（P〈0．01）,差异有统计学意义。（2）与S组相比,MI组、Cap组和val组心肌CT-1及gp130mRNA表达增强（P〈0．01）,差异有统计学意义;与MI组相比,Val组CT-1及gp130mRNA表达均显著减弱（P〈0．05）,差异有统计学意义;Cap组gpl30mRNA表达显著减弱（P〈0．05）,差异有统计学意义,CT-1mRNA差异无统计学意义（P〉0．05）。结论大鼠MI后CT-1及gp130mRNA的过度表达与MI后CCN重塑的发生密切相关;缬沙坦改善MI后CCN重塑的机制还可能与抑制CT-1及gp130基因的过度表达有关,值得进一步研究。     

哮喘小鼠肺脏组织肾素-血管紧张素系统相关组分表达 及AT1R拮抗剂对其影响

目的：探讨肾素-血管紧张素系统（RAS）与哮喘发生的关系,为哮喘发病机制的研究和治疗提供理论依据。方法：复制小鼠哮喘模型,小鼠分为对照组、模型组、坎地沙坦低剂量组及高剂量组,采集小鼠血清,测量血清中血管紧张素Ⅱ (AngⅡ)与血管紧张素Ⅰ(AngⅠ)的含量;通过Western blotting和RT-PCR观察RAS中血管紧张素原(AGT)、血管紧张素转换酶(ACE)、血管紧张素Ⅱ 1型受体（AT₁R）和2型受体（AT₂R）在各组小鼠肺组织中的表达。结果：模型组小鼠血清AngⅡ含量较对照组增高（P<0.05）,坎地沙坦组与模型组比较无明显变化（P>0.05）。各组小鼠血清中AngⅠ含量比较差异无统计学意义（P>0.05）。模型组小鼠AT1R和ACE蛋白表达较对照组明显增加（P<0.05）,坎地沙坦组AT₁R表达与模型组比较明显降低(P<0.05),ACE无明显变化（P>0.05）。AT₂R蛋白表达各组间比较差异无统计学意义（P>0.05）。模型组小鼠ACE mRNA表达较对照组明显增加（P<0.05）,坎地沙坦组与模型组比较差异无统计学意义（P>0.05）。模型组小鼠AT1R mRNA表达较对照组明显增加（P<0.05）,坎地沙坦组较模型组明显降低（P<0.05）。模型组AT2R mRNA较对照组明显降低（P<0.05）,坎地沙坦组较模型组明显增加（P<0.05）。各组AGT mRNA表达无明显变化（P>0.05）。  结论：在小鼠哮喘发病过程中,RAS活化参与了哮喘的发病过程,并且AT₁R拮抗剂坎地沙坦可以逆转ACE、AT₁R和AT₂R表达的改变。     

siR N A 干扰 A T1 R 基因调控链脲佐菌素诱导NIT －1细胞凋亡的实验研究

目的：用siRNA干扰技术沉默小鼠胰岛素瘤NIT－1细胞血管紧张素Ⅱ1型受体（ AT1R）基因,探讨其对链脲佐菌素（STZ）诱导的胰岛素瘤细胞凋亡的影响。方法针对小鼠AT1R基因,设计并合成3对siRNA序列,脂质体法转染至NIT－1细胞,荧光显微镜观察荧光强度检测转染效率,Real－time PCR检测AT1R mRNA表达量判断不同干扰序列及干扰时间的基因沉默效果;分4组：空白组不予任何干预,STZ组予5 mmoL／L STZ干预30 min,si－AT1R组予40 nmol／L si－AT1R转染24 h,si－AT1R＋STZ组予40 nmoL／L si－AT1R转染24 h后5 mmoL／L STZ干预30 min;Real－time PCR检测Caspase－3 mRNA表达量,Hoechst33342染色荧光显微镜和Annex-in V－FITC／PI流式细胞术检测细胞凋亡率。结果40 nmol／L siRNA转染的荧光强度最强,转染后AT1R mRNA表达量明显下降,si－AT1R－2转染24 h的沉默效果最佳（92.20％）;Caspase－3 mRNA表达量：STZ组与空白组比增加了2.37倍（P＜0.05）,si－AT1R＋STZ组与STZ组比减少了11.28％,但差异无统计学意义;细胞凋亡率：STZ组与空白组比增加了3.27倍（P＜0.05）,si－AT1R＋STZ组与STZ组比减少了26.82％（P＜0.05）。结论本研究建立了稳定的胰岛细胞AT1R基因沉默模型;RNA干扰沉默胰岛细胞AT1R基因可通过下调Caspase－3 mRNA表达量降低STZ诱导的细胞凋亡率,提示AT1R介导了STZ诱导的胰岛细胞凋亡过程。     

血管紧张素转换酶抑制剂与血管紧张素Ⅱ受体拮抗剂对动脉内膜损伤后增生的影响

目的：观察血管紧张素转换酶抑制剂（ACEI）captopril与血管紧张素Ⅱ(AngⅡ)的AT₁受体拮抗剂valsartan对损伤动脉内膜增生的影响。 方法:以兔右颈总动脉内膜剥脱为实验模型,随机分为单纯损伤组、captopril组及valsartan组。captopril组及valsartan组术前1 d至术后14 d分别给予captopril 2 mg•kg^-1•d^-1与valsarta 10 mg•kg^-1•d^-1,单纯损伤组不给药。检测各组术前及术后7、14 d血浆组织纤溶酶原激活物（t-PA）、纤溶酶原激活剂抑制物-1（PAI-1）、血浆内皮素（ET）水平,并于术后14 d对各组血管内膜厚度及管腔狭窄度行病理形态学观察。 结果：captopril组及valsartan组血浆PAI-1、ET水平及内膜的厚度、管腔狭窄度均明显低于单纯损伤组(P<0.05)。 结论：captopril与valsartan均可抑制动脉损伤后内膜的增生。     

同型半胱氨酸在大鼠血管平滑肌细胞上通过激活ERK1/2信号通路促进血管紧张素Ⅱ受体1表达

目的：在原代大鼠血管平滑肌细胞(VSMC)上观察同型半胱氨酸(Hcy)对血管紧张素II受体1(AT1R)的蛋白表达的影响。     

RAGE、AT1R在糖尿病大鼠脑组织的表达及机制

目的探讨高级糖基化终末产物受体(RAGE)、血管紧张素Ⅱ受体-1(AT1R)在糖尿病(DM)脑组织病变的可能机制。方法 20只SD大鼠随机分为对照组和糖尿病组。第16周末行脑磁共振检查;于20周末处死大鼠,留取脑组织标本,行HE染色检测其病理学改变;采用免疫组化SP法检测脑组织RAGE、AT1R、基质金属蛋白酶9(MMP9)及胶原纤维酸性蛋白(GFAP)的表达,并进行相关性分析。结果糖尿病组大鼠磁共振显示大脑白质病变,T1WI低信号、T2WI高信号;组织病理学显示脑组织小血管周隙明显增宽,未见坏死及炎细胞浸润;糖尿病组脑组织RAGE、AT1R、MMP9阳性细胞数较对照组明显升高,差异有统计学意义(P<0.05),GFAP阳性细胞数无明显变化;糖尿病组脑组织RAGE、AT1R呈正相关(P=0.015);糖尿病组大鼠MMP9与RAGE、AT1R呈正相关(P=0.001,0.037)。结论 DM大鼠白质病变的病理表现是脑小血管周围的水肿,其机制可能与RAGE、AT1R及MMP9表达有关。     

脂质体瞬时转染siRNA抑制肾小管上皮细胞AngⅡ 1型受体表达

目的建立有效的脂质体瞬时转染法,转染小分子RNA（siRNA）,抑制人肾小管上皮细胞（human kidneytubular epithelial cells,HKC）血管紧张素Ⅱ（AngⅡ）1型受体（AT1R）的表达。方法针对人AT1R mRNA135到156位点,由美国Ambion公司设计并合成AT1R siRNA序列,以脂质体法瞬时转染至HKC,利用RT-PCR及Western blot技术检测HKC内AT1R mRNA及蛋白表达。结果AT1R siRNA转染对人肾小管上皮细胞AT1R的抑制效果在48h达到最大抑制作用;转染后,HKC细胞AT1R mRNA表达下调（68.5±6.4）%,AT1R蛋白表达下调（80.7±5.3）%,与对照组比较存在显著性差异（P〈0.001）。使用AngⅡ刺激,特异性AT1R siRNA转染组AT1R表达明显下降,无转染及非特异性转染组AT1R表达升高。特异性AT1R siRNA转染HKC细胞后,其炎症因子单核细胞趋化蛋白-1（MCP-1）表达明显下降。结论本研究利用脂质体瞬时转染siRNA方法,成功抑制肾小管上皮细胞表达AT1R,为后续相关研究提供实验方法。     

血管紧张素Ⅱ对肝癌细胞增殖的影响及其机制研究

目的:研究血管紧张素Ⅱ对肝癌HepG2细胞增殖的影响及其机制.方法:采用CCK-8法测定不同浓度血管紧张素Ⅱ作用24、48 h对HepG2细胞增殖的影响.通过蛋白质免疫印迹法测定血管紧张素Ⅱ处理后HepG2细胞内细胞外信号调节激酶(ERK)1/2和血管紧张素Ⅱ-1型受体(AT1R)蛋白表达水平.结果:作用24 h,10...     

津力达颗粒对糖尿病大鼠肾及心血管组织肾素-血管紧张素系统的影响

目的 观察津力达颗粒(JLG)对实验性糖尿病大鼠肾脏、心脏和腹主动脉组织肾素-血管紧张素系统(RAS)的影响,探讨JLG保护糖尿病患者肾脏及心血管的可能机制.方法 采用随机数字表法将大鼠分为糖尿病模型组20只和正常对照组(CON组)10只.CON组喂以普通饲料;糖尿病模型组喂以高脂饲料,喂养4周后用30 mg/kg链脲佐菌素(STZ)腹腔注射诱导糖尿病模型.诱导糖尿病模型成功后,再随机分成糖尿病津力达治疗组[DM+JLG组:JLG3g/(kg·d)灌胃]和糖尿病未治疗组(DM组),每组10只.8周后取肾、心脏及腹主动脉,采用ELISA法测定各组织匀浆血管紧张素Ⅰ(Ang Ⅰ)、血管紧张素Ⅱ(AngⅡ)水平,蛋白质印迹分析法检测血管紧张素Ⅱ1型受体(AT1 R)、血管紧张素Ⅱ2型受体(AT2 R)的表达.结果 与CON组相比,DM组大鼠双肾质量/体质量、心脏质量/体质量、血糖、24 h尿蛋白增加(P＜0.05),体质量减少(P＜0.05),肾脏、心室肌和腹主动脉组织AngⅠ、AngⅡ、AT1R、AT2R水平升高(P＜0.05).与DM组相比,DM+JLG组大鼠双肾质量/体质量、血糖、24 h尿蛋白降低(P＜0.05),体质量增加(P＜0.05),肾脏、心室肌和腹主动脉组织Ang Ⅰ、AngⅡ、AT1R、AT2R水平降低(P＜0.05).结论 JLG能降低实验性糖尿病大鼠肾脏、心脏及腹主动脉组织血管紧张素及其受体水平,有利于保护肾脏及心血管系统.     

肾素原受体在糖尿病视网膜病变中的作用及其机制研究

目的：观察糖尿病视网膜病变发生过程中肾素原受体（PRR）及血管紧张素Ⅱ受体2（AT2R）的表达水平及视网膜神经细胞凋亡情况,阐明 PRR 与糖尿病视网膜神经细胞凋亡的关系。方法建立链尿佐菌素诱导的糖尿病 SD 大鼠模型,建模成功后分别在4周、8周和12周用免疫组化法检测 CD14及8-羟脱氧鸟苷分子的表达,检测糖尿病及对照组视网膜 AT2R、PRR mRNA 的表达及细胞外信号调节激酶（ERK1/2）、磷酸化 ERK1/2（p-ERK1/2）蛋白的表达。结果各病程 SD 大鼠视网膜 AT2R 和 PRR 的 mRNA 表达水平较对照组明显升高（P <0.05）,随病程的延长表达量随之增多。病程越长糖尿病组大鼠视网膜组织凋亡细胞数量越多,各阶段病程 CD14染色未见明显新生血管。通过相关性分析显示,PRR 和 AT2R 表达水平与神经节细胞凋亡相关。各病程大鼠视网膜 ERK1/2、p-ERK1/2蛋白的表达量显著高于对照组。结论糖尿病视网膜病变中 PRR 和 AT2R 的表达与大鼠糖尿病视网膜病变的神经节细胞凋亡相关,可能通过增加 ERK 的磷酸化水平发挥功能作用。