自发性高血压大鼠肥厚左室心肌组织微小RNA-1与缝隙连接蛋白43的改变

目的观察自发性高血压大鼠(SHR)肥厚左室心肌组织微小RNA-1(miRNA-1)、缝隙连接蛋白43(Cx43)表达的变化及其关系,以探讨高血压性心肌肥厚发生室性心律失常(VA)的分子机制。方法 10只17周龄雄性SHR大鼠做为左室肥厚组(LVH组),10只8周龄雄性SHR大鼠做为对照组,通过病理学、心肌细胞横径的测量、实时荧光定量聚合酶链反应、免疫组织化学法及western blotting检测等方法 ,比较两组大鼠左室心肌组织病理学改变、miRNA-1及Cx43蛋白表达。结果①与对照组比较,LVH组的收缩压、舒张压升高,左室质量指数及心肌细胞横径均明显增大(P均0.05);miRNA-1表达水平明显升高,以及Cx43蛋白表达水平降低(0.27±0.10vs0.60±0.13,P0.05);②LVH组大鼠左室心肌组织miRNA-1与Cx43蛋白的表达水平呈显著负相关(r=-0.661,P0.05)。结论 miRNA-1可能通过抑制Cx43表达而参与高血压LVH发生VA。     

微小RNA-1调控自发性高血压大鼠肥厚左心室心肌组织Kir2.1蛋白的表达

目的 观察微小RNA-1(miRNA-1)调控自发性高血压大鼠(SHR)肥厚左心室心肌组织中内向整流钾通道2.1(Kir2.1)蛋白表达的变化及其意义.方法 17周龄雄性SHR 16只随机分为干预组(n=6)、阴性对照组(n=5)和空白对照组(n=5),通过脂质体瞬时转染技术,干预组由尾静脉注射miRNA-1抑制剂(A...     

微小RNA-1调控自发性高血压大鼠肥厚左室心肌组织连接蛋白43的表达

目的观察微小RNA-1(miRNA-1)对自发性高血压大鼠(SHRs)肥厚左室心肌组织中连接蛋白43(Cx43)表达的调控及其意义。方法 18只17周龄雄性SHRs随机分为干预组(n=6)、阴性对照组(n=6)和空白对照组(n=6),通过脂质体瞬时转染技术,干预组由尾静脉注射miRNA-1抑制剂,两对照组分别注入miRNA-1抑制剂阴性对照和无血清培养基混合物,并通过实时荧光定量PCR、免疫组织化学法及western blot等技术,检测大鼠左室心肌组织miRNA-1及Cx43蛋白表达水平的改变。结果与阴性对照组和空白对照组比较,干预组miRNA-1表达水平明显降低,伴随着Cx43蛋白表达水平增高(0.45±0.15 vs 0.27±0.14,0.23±0.10,P均<0.05)。结论抑制miRNA-1表达能使SHR肥厚左室心肌组织Cx43蛋白水平升高。     

不同降压药物对自发性高血压大鼠模型左室心肌细胞中TRPC3及TRPC6表达的影响

目的:探讨缬沙坦、雷米普利及氨氯地平对自发性高血压大鼠（SHR）左室心肌中瞬时受体通道蛋白C亚族3及6(TRPC3及TRPC6)表达的影响。方法: 将24只12周龄SHR大鼠随机分为4组,即SHR组、缬沙坦组、雷米普利组及氨氯地平组,每组6只。另以6只同龄的Wistar Kyoto大鼠(WKY)为正常对照组。给药4周后,检测各组大鼠的血压、左室质量指数、左室心肌细胞横径;RT-PCR及Western Blot检测TRPC3及TRPC6 mRNA 及其蛋白的表达。结果: SHR组血压、左室质量指数及左室心肌细胞横径均明显高于对照组（P<0.05）,3个药物组上述指标均较SHR组降低（P<0.05）;5个组均有TRPC3及TRPC6的表达,SHR组TRPC3及TRPC6 mRNA及其蛋白的表达显著高于对照组（P<0.05）,3个药物组TRPC3 mRNA及TRPC6 mRNA及其蛋白的表达均显著低于SHR组（P<0.05）,缬沙坦组TRPC3 mRNA及其蛋白表达的减少最显著（P<0.05）;3个药物组TRPC6 mRNA及其蛋白的表达有所下降,但组间比较差异无显著性。结论: SHR组及对照组大鼠均有TRPC3及TRPC6的表达,TRPC3及TRPC6可能共同参与调节心肌肥厚的病理生理过程;缬沙坦可能通过抑制TRPC3蛋白的表达参与逆转左室肥厚的过程。     

ERK表达及活化在自发性高血压大鼠心肌肥厚中作用的研究

目的　以SHR大鼠作为自发性高血压动物模型 ,研究ERK表达及活化在高血压并发左心室肥厚 (LVH)中的作用。方法　SHR大鼠按年龄分为 8周、16周和 2 4周三组 ,以Wistar大鼠作为对照。ERK表达及活性定量测定采用WesternBlot方法。结果　SHR左室质量指数与磷酸化ERK水平正相关。 2 4周龄SHR大鼠基础ERK表达水平较 8周龄和 16周龄减少 ,亦明显低于同龄Wistar大鼠 (P =0 0 0 3) ;SHR大鼠ERK活化程度高于同龄Wistar大鼠 ,随年龄增加 ,SHR磷酸化ERK表达量增加。结论　ERK的活化参与高血压心肌肥厚的发病。     

ERK表达及活化在自发性高血压大鼠心肌肥厚中作用的研究

目的以SHR大鼠作为自发性高血压动物模型,研究ERK表达及活化在高血压并发左心室肥厚(LVH)中的作用.方法 SHR大鼠按年龄分为8周、16周和24周三组,以Wistar大鼠作为对照.ERK表达及活性定量测定采用Western Blot方法.结果 SHR左室质量指数与磷酸化ERK水平正相关.24周龄SHR大鼠基础ERK 表达水平较8周龄和16周龄减少,亦明显低于同龄Wistar大鼠(P=0.003);SHR大鼠ERK活化程度高于同龄Wistar大鼠,随年龄增加,SHR磷酸化ERK表达量增加.结论 ERK的活化参与高血压心肌肥厚的发病.     

丹参对自发性高血压大鼠左室肥厚及心肌肿瘤坏死因子表达影响

目的观察丹参对自发性高血压大鼠左室肥厚作用及左室心肌肿瘤坏死因子(TNF-α)的影响,并探讨其作用机制.方法实验用WKY大鼠做阴性对照组,SHR大鼠分为对照组和治疗组.治疗组给予丹参注射液腹腔内注射12周,其余两组分别注射相当容积的蒸馏水.测量大鼠尾动脉收缩压(SBP)及左心室重量指数(LVMI).应用HE、VG染色、免疫组织化学的方法,结合计算机图像分析技术,检测心肌细胞的直径和面积、心肌组织胶原体积比例(CVF)、血管周围胶原面积和管腔面积比例(PVCA)以及左心室心肌TNF-α表达.结果与WKY大鼠相比,20周龄SHR大鼠的SBP、LVMI、心肌细胞的直径、面积、CVF、PVCA显著增加,TNF-α表达上调,用丹参治疗后,SHR除收缩压外余指标均显著性下降(P＜0.05).结论长期应用丹参治疗可预防和逆转高血压大鼠左室肥厚形成,其机制可能与丹参降低心肌TNF-e表达有关.     

自发性高血压大鼠心室重构及脂联素受体1的表达

目的 观察自发性高血压大鼠(SHR)心室重构情况和心肌脂联素受体1(AdipoR1)及其mRNA的表达水平.方法 8只12w龄雄性自发性高血压大鼠为实验组(SHR组),8只12周龄雄性京都Wistar大鼠为对照组(WKY组).喂养12w后,各组大鼠分别超声心动图测定左室舒张末期内径(LVEDD)、室间隔厚度(IVST)、左室后壁厚度(LVPWT)、二尖瓣口舒张早期峰值流速(E峰)、舒张晚期血流峰值流速(A峰)并计算E/A比值;计算左室重量指数(LVWI);HE染色和Masson染色观察心肌组织形态学改变,并测定心肌胶原容积分数(CVF)和羟脯氨酸(Hyp)的含量;RT-PCR方法检测心肌组织AdipoR1 mRNA表达水平;Western印迹方法检测心肌组织AdipoR1蛋白表达水平.结果 与WKY组相比,SHR组IVST、LVPWT、LVWI均增大;LVEDD和E/A均减小;心肌细胞排列紊乱,间质成纤维细胞肥大增生,CVF和Hyp的含量均增多;AdipoR1 mRNA及AdipoR1蛋白表达均显著降低.结论 SHR大鼠有心室重构发生,心肌AdipoR1 mRNA和AdipoR1蛋白表达均水平下调,提示SHR大鼠心室重构发生与AdipoR1的变化有关.     

自发性高血压大鼠心肌增殖细胞核抗原（PCNA）的表达以及厄贝沙坦和咪哒普利的影响

目的　探讨自发性高血压大鼠 (SHR)左心室肌增殖细胞核抗原 (PCNA)的表达以及咪哒普利、厄贝沙坦的影响。　方法　选用 13周龄的SHR30只 ,雌性 9只 ,雄性 2 1只 ,体重 2 2 8 5± 39g ,随机分为三组 ,使得每组雌性 3只 ,雄性 7只 ,分别设为SHR组 ,厄贝沙坦组 ,咪哒普利组 ;另选同源同系Wistar Kyoto大鼠 (WKY大鼠 ) 10只 ,雌性 5只 ,雄性 5只 ,体重 2 0 6 1g± 4 9 1g,作为正常对照组 (WKY组 )。实验期 14周。观察指标 :血压、左室重量 /体重 (LVW/BW )、左室厚度 /体重、心肌PCNA蛋白水平。结果　SHR组血压、LVW/BW、左室厚度 /体重均增高 ,心肌PCNA蛋白的表达明显增加 ;咪哒普利组、厄贝沙坦组血压、LVW/BW、左室厚度 /体重、心肌增殖核抗原 (PCNA)蛋白的表达均比SHR组低。结论　 2 6周龄SHR左心室肌PCNA蛋白的表达明显升高 ,咪哒普利、厄贝沙坦不仅可以良好地控制血压 ,而且可以抑制自发性高血压大鼠左心室重塑 ,并可以降低SHR左心室肌PCNA蛋白的表达 ,二者对SHR左室肥厚的抑制效应可能与降低PCNA蛋白的表达有关系。     

依那普利和缬沙坦对自发性高血压大鼠心肌细胞凋亡的影响

目的观察依那普利和缬沙坦在降压的同时对自发性高血压大鼠(SHR)左室肥厚过程中心肌细胞凋亡及凋亡相关蛋白bc l-2、bax表达的影响。方法14周龄雄性SHR随机分为三组(n=6),依那普利组:依那普利30 mg.kg-1.d-1;缬沙坦组:缬沙坦30 mg.kg-1.d-1;对照组:等量饮用水灌胃,干预8周。分别采用流式细胞术Annexin V/PI法和免疫组化SABC法检测心肌细胞凋亡指数及凋亡相关蛋白bc l-2、bax的表达。结果缬沙坦及依那普利治疗组大鼠血压及左室重量/体重明显降低,心肌细胞凋亡指数明显降低(P<0.01);依那普利组明显降低bax蛋白表达,增加bc l-2蛋白表达(P<0.01)。缬沙坦组明显降低bax蛋白表达(P<0.01)。结论依那普利和缬沙坦对SHR左室肥厚过程中心肌细胞凋亡均有抑制作用。两者均通过增加bc l-2/bax比率而抑制心肌细胞凋亡,逆转高血压引起的左室肥厚。     

自发性高血压大鼠心脏重构与ACE2 mRNA的表达

目的:观察不同月龄的自发性高血压大鼠(SHR)的心脏血管紧张素转换酶2(ACE2)mRNA表达水平,探讨心脏重构与ACE2的内在联系。方法:将12周龄雄性SHR 18只和12周龄WKY Wistar-Kyoto rats大鼠18只随机分为两组,从WKY大鼠组和SHR组中各抽取9只处死,剩余的9只再喂养12周后处死。测量大鼠心脏的质量(HW)与体质量(BW)并计算HW/BW的比值。以实时定量RT-PCR法检测ACE2 mRNA的表达。结果:①与同周龄WKY大鼠组比较,SHR组HW/BW的比值显著增加(P0.01);与12周龄SHR组比较,24周龄SHR组的HW/BW显著增加(P0.05)。②与同周龄的WKY大鼠组比较,SHR组ACE2 mRNA的表达显著降低(P0.01);与12周龄的SHR组比较,24周龄的SHR组ACE2 mRNA的表达显著降低(P0.01)。结论:自发性高血压大鼠心脏重构伴随着心脏中ACE2 mRNA的表达下调。     

Nifedipine in divided doses does not reverse left ventricular hypertrophy in spontaneously hypertensive rats.

This study investigated whether nifedipine administered in divided daily doses would diminish left ventricular hypertrophy (LVH) in spontaneously hypertensive rats (SHR). We administered nifedipine (12 mg/kg/day) in 3 divided doses by gastric gavage to 15-week-old male SHR (n = 10) for 4 weeks. Age- and sex-matched SHR served as controls (n = 10). Left ventricular (LV) function was evaluated by LV catheterization and cardiac output was determined by the thermodilution method. Plasma renin activity (PRA) and plasma norepinephrine levels were measured. Nifedipine significantly decreased blood pressure (p less than 0.01), shortened time constant T (p less than 0.05), and increased cardiac output (p less than 0.05). Nifedipine did not impair the LV systolic and diastolic indices during acute afterload elevation with angiotensin II. LV weight was similar in the 2 groups of rats. While PRA was unaltered, plasma norepinephrine levels were higher in the nifedipine-treated rats (p less than 0.05). These data indicate that nifedipine in 3 divided doses reduced blood pressure in SHR without compromising cardiac function but did not reverse LVH. The short hypotensive duration of nifedipine and its enhancement of sympathetic nervous activity may be responsible for the failure to reverse LVH, despite adequate blood pressure control.     

沉默信息调节因子相关酶3在自发性高血压大鼠心肌高表达与左心室肥厚相关

目的观察沉默信息调节因子相关酶3(sirtuin3)在自发性高血压大鼠(SHR)心肌中的表达,并探讨sirtuin3在高血压所致左心室肥厚(LVH)中的作用。方法 24只29周龄SHR随机分为SHR30周龄组(喂养1周,n=11)和SHR38周龄组(喂养9周,n=13),另选20只29周龄Wistar-Kyoto(WKY)大鼠随机分为WKY30周龄组(喂养1周,n=10)和WKY38周龄组(喂养9周,n=10)作为正常对照。各组测定尾动脉收缩压和左心室质量(LVM)/体质量。Masson染色法分析左心室肌间质纤维化程度,心脏超声测定心功能。采用免疫组化,Western-blot及实时荧光定量PCR来检测心肌组织中sirtuin3的蛋白及mRNA表达。结果与WKY30、38周龄组大鼠比较,SHR30、38周龄组的收缩压[30周龄(189.0±6.8)比(103.4±3.6)mmHg;38周龄(205.6±10.9)比(116.3±4.3)mmHg]、LVM/体质量[30周龄(2.94±0.11)比(2.56±0.21);38周龄(3.21±0.15)比(2.68±0.24)]、左心室收缩末期内径[30周龄(4.27±0.13)比(3.59±0.08)mm;38周龄(5.46±0.14)比(4.21±0.08)mm]、舒张末期室间隔厚度[30周龄(2.63±0.15)比(2.09±0.06)mm;38周龄(2.82±0.09)比(2.35±0.08)mm]、舒张末期左心室后壁厚度[30周龄(2.78±0.12)比(2.15±0.09)mm;38周龄(2.99±0.12)比(2.44±0.07)mm]、sirtuin3mRNA和蛋白表达升高(均P<0.05);左心室短轴缩短率、左心室舒张末期内径降低(均P<0.05),SHR大鼠表现出左心室明显肥厚,左心室收缩及舒张功能明显减低,并随着周龄的延长,心肌肥厚及心功能障碍加重(P<0.05)。结论心肌组织sirtuin3高表达与左心室肥厚密切相关。     

Voltage gated K+ channel expression in arteries of Wistar-Kyoto and spontaneously hypertensive rats

BACKGROUND: We have previously demonstrated differences in the gene expression of voltage-gated K v1.X channel alpha-subunits in arteries from Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs). The purpose of this study was to test the hypothesis that these differences are also present at the protein level. METHODS: Proteins were isolated from the aorta, mesenteric (MAs) and tail arteries (TAs) of 12- to 15-week-old male WKY and SHR, and analyzed by immunoblotting. K(v) currents were recorded from MA myocytes by patch clamp methods. RESULTS: Expression of Kv1.2, Kv1.5, and Kv2.1 was higher in MAs but was not different in aortas of SHRs as compared to WKYs. In the TA, expression of Kv1.2 and Kv1.5 was higher while that of Kv2.1 was lower in SHR compared to WKY. In the MA, the larger expression of an 80 kDa species of Kv1.2 in SHRs was associated with a lower expression of a 60 kDa species. Kv2.1 gene expression was larger in MAs from SHRs but not different in TAs. K(v) currents associated with Kv1.X and Kv2.1 channels were both larger in MA myocytes from SHRs but less than expected based upon differences in K(v) alpha-subunit protein expression. CONCLUSIONS: For the MA, K(v) protein expression and current components between WKYs and SHRs were qualitatively consistent, but differences in gene and protein expression were not closely correlated. The higher expression of K(v) subunits in small mesenteric arteries (SMAs) of SHR would tend to maintain normal myogenic activity and vasoconstrictor reserve, and could be viewed as a form of homeostatic remodeling.     

Exercise training prevents the microvascular rarefaction in hypertension balancing angiogenic and apoptotic factors: role of microRNAs-16, -21, and -126

Aerobic exercise training (ET) lowers hypertension and improves patient outcomes in cardiovascular disease. The mechanisms of these effects are largely unknown. We hypothesized that ET modulates microRNAs (miRNAs) involved in vascularization. miRNA-16 regulates the expression of vascular endothelial growth factor and antiapoptotic protein Bcl-2. miRNA-21 targets Bcl-2. miRNA-126 functions by repressing regulators of the vascular endothelial growth factor pathway. We investigated whether miRNA-16, -21 and -126 are modulated in hypertension and by ET. Twelve-week-old male spontaneously hypertensive rats (SHRs; n=14) and Wistar Kyoto (WKY; n=14) rats were assigned to 4 groups: SHRs, trained SHRs (SHR-T), Wistar Kyoto rats, and trained Wistar Kyoto rats. ET consisted of 10 weeks of swimming. ET reduced blood pressure and heart rate in SHR-Ts. ET repaired the slow-to-fast fiber type transition in soleus muscle and the capillary rarefaction in SHR-Ts. Soleus miRNA-16 and -21 levels increased in SHRs paralleled with a decrease of 48% and 25% in vascular endothelial growth factor and Bcl-2 protein levels, respectively. Hypertension increased Bad and decreased Bcl-x and endothelial NO synthase levels and lowered p-Bad(ser112):Bad ratio. ET in SHR-Ts reduced miRNA-16 and -21 levels and elevated vascular endothelial growth factor and Bcl-2 levels. ET restored soleus endothelial NO synthase levels plus proapoptotic and antiapoptotic mediators in SHR-Ts, indicating that the balance between angiogenic and apoptotic factors may prevent microvascular abnormalities in hypertension. miRNA-126 levels were reduced in SHRs with an increase of 51% in phosphoinositol-3 kinase regulatory subunit 2 expression but normalized in SHR-Ts. Our data show that ET promoted peripheral revascularization in hypertension, which could be associated with regulation of select miRNAs, suggesting a mechanism for its potential therapeutic application in vascular diseases.     

Endothelin-1-receptor-mediated responses in resistance vessels of young and adult spontaneously hypertensive rats

OBJECTIVE: To assess whether primary changes in endothelin-1 (ET-1) receptor responsiveness or secondary vessel functional modifications could characterize the effects evoked by ET-1 in the mesenteric vascular bed (MVB) of prehypertensive 5-week-old and 12-week-old spontaneously hypertensive rats (SHRs). DESIGN AND METHODS: We used male 5-week-old and 12-week-old SHRs and sex- and age-matched Wistar-Kyoto (WKY) rats as controls. ET-1 receptor responsiveness was evaluated by ET-1 (0.04-2 micromol/l) concentration-response curves and repeated with indomethacin and BQ-123 (0.1-0.5 micromol/l), the latter a selective ETA receptor antagonist. ETB receptor responsiveness was tested by sarafotoxin S6c (1-100 nmol/l) and IRL-1620 (0.1-10 nmol/l) concentration-response curves, obtained in the noradrenaline-precontracted MVB. RESULTS: At 5 weeks of age, ET-1 induced a similar concentration-dependent contraction in SHRs and WKY rats, with an overlapping BQ-123 pA2 value (negative common logarithm of the antagonist that produces an agonist dose ratio of 2) in the two strains. Indomethacin was ineffective in both groups. Sarafotoxin S6c and IRL-1620 both evoked an ETB-mediated, significant relaxation, only in WKY rats. In 12-week-old SHRs, ET-1 evoked a markedly increased maximal effect compared with the response in WKY rats (P< 0.01); this was prevented by treatment with indomethacin. The BQ-123 pA2 value was higher in SHRs than in WKY rats (P< 0.01). Both sarafotoxin S6c and IRL-1620 evoked a significant concentration-dependent relaxation in WKY rats, which was not detected in SHR preparations. CONCLUSIONS: Our results could suggest that the different responses evoked by ET-1 in the MVB of SHRs during the onset of hypertension may be related partially to primary alterations in the ET-1 receptorial pattern and partially to the onset of high blood pressure, leading to an impairment in the haemodynamic balance.     

结缔组织生长因子与高血压大鼠心肌纤维化相关性及伊贝沙坦的干预研究

目的探讨结缔组织生长因子(CTGF)在高血压大鼠心肌纤维化发生发展中的作用,以及伊贝沙坦改善高血压所致心室重构和心肌纤维化可能的作用机制。方法20只12周龄雄性自发性高血压大鼠(SHR)随机分为SHR组和伊贝沙坦(IRB)组各10只,IRB组每只大鼠予以伊贝沙坦50 mg.kg-1.d-1灌胃,给药时间12周,同时取10只12周龄雄性Wistar大鼠作为对照组(WKY组),用免疫组织化学的方法对转化生长因子β1(TGF-β1)、CTGF在3组大鼠的左室心肌的分布及表达进行半定量分析;用逆转录-聚合酶链反应检测TGF-β1、CTGF mRNA在心肌表达水平;用MOSSON染色法观察左室心肌胶原形态,图像分析测量胶原容积分数(CVF)和血管周围胶原面积(PVCA)。结果(1)左室重量指数(LVI)、CVF、PVCA在SHR大鼠组明显高于WKY大鼠组(P<0.01);与SHR组比较,伊贝沙坦组则显著降低(P<0.05)。(2)CTGF主要在血管平滑肌和心肌间质中表达,相关分析表明:CTGF与TGF-β1(r=0.562,P<0.05)、CVF(r=0.715,P<0.01)、PVCA(r=0.786,P<0.01)呈正相关;(3)CTGF及其mRNA在SHR组左室心肌中的表达较WKY组明显增强(P<0.05),与SHR组比较,IRB组则明显减少。结论高血压大鼠心室肌CTGF表达增加,伊贝沙坦能抑制高血压大鼠心室肌CGTF表达,且明显改善了高血压心室重构和心肌纤维化。