摘要
背景:
心肌肥大是心脏对于高血压、心梗和心肌病等多种刺激因素所作出代偿反应的结果,然而它不是无限度的,如果病因历久而不能被消除,则肥大心肌的功能便不能长期维持在正常水平而最终转向心力衰竭,甚至发生猝死。心肌肥大往往伴随有糖代谢升高和脂肪酸氧化降低,对于细胞内基质和代谢水平的改变是心肌肥大的诱因还是结果,一直是研究人员争论的焦点。但是心肌肥大的发展是多种因素作用的结果,之前也有研究报道,缺乏线粒体脂肪酸氧化酶可以导致小儿心肌肥大,在动物模型中干扰脂肪酸代谢也可以成功诱导心肌肥大,这些资料都证明基质成分在心肌肥大的发展过程中起着至关重要的作用。
血管内皮生长因子(vascular endothelial growth factor,VEGF)是1989年由Ferrara等在牛垂体滤泡星形胶质细胞体外培养液中分离纯化出来的,是作用于血管内皮细胞的生长因子,也是目前发现的最强烈的增加血管通透性物质之一,有文献报道在肥大心肌细胞中VEGF的表达增多。
过氧化物酶体增生物激活受体(peroxisome proliferator-activated receptor,PPARs)是一组调节脂肪酸代谢的配体激活核受体转录因子,并在炎症反应通路中起着重要作用。PPARs主要包括三种亚型:PPARα、PPARβ和PPARγ,Gilde等已经通过新生大鼠心肌细胞和H9C2细胞的实验研究证明,PPARβ是心肌细胞中最主要的PPARs亚型,在心脏的脂类代谢中起着重要作用,并可以促进肥大细胞的脂肪酸代谢。
目前还没有关于VEGF在心肌肥大中对脂肪酸代谢的报道,我们主要研究心肌肥大中VEGF对PPARβ的影响以及其在心肌肥大脂肪酸代谢中的调节作用,为下一步临床心肌肥大的防治探索道路。
目的:
1.构建心肌肥大模型,培养新生大鼠心肌细胞和H9C2细胞;
2.探讨肥大心肌VEGF的表达及其对PPARβ表达、脂肪酸代谢水平的影响。
方法:
1.心肌肥大动物模型的建立:实验大鼠随机分为假手术组(n=8)、手术组(n=8)和药物组(n=8)。标准大鼠饲料喂养1周后,手术组实验大鼠异氟烷麻醉后气管插管,并持续气管吸入异氟烷保持麻醉,仰卧位,腹部切口,在肾上水平7-0线打结缩窄腹主动脉;假手术组只是不进行腹主动脉结扎,其他手术操作和手术组一致;药物组在手术组相同手术操作基础上自第二天起连续应用VEGF抑制剂哌加他尼钠钠。15d后收集实验大鼠心脏备用。
2.新生鼠心室肌细胞的培养:1-3d大鼠幼鼠麻醉,无菌条件下开胸取出心脏,0.08%胰蛋白酶液消化,用10%胎牛血清DMEM培养液制成细胞悬液,置于37℃含5%CO2培养箱中,根据心肌细胞和非心肌细胞贴壁时间的不同采用差速贴壁培养。细胞随机分为三组:对照组(n=10)、PE组(n=10)和实验组(n=10),PE组在细胞培养稳定后加苯肾上腺素(PE,phenylephrine)培养;实验组在细胞培养稳定后加PE和哌加他尼钠钠培养,之后进行下一步处理:1.细胞更换培养液,对照组培养液含【~3H】亮氨酸,培养24h;PE组培养液含PE和【~3H】亮氨酸,培养24h;实验组培养液含PE、哌加他尼钠钠和【~3H】亮氨酸,培养24h。之后用PBS清洗细胞,10%三氯乙酸处理细胞,沉淀蛋白,用氢氧化钠溶解蛋白沉淀,闪烁计数器读数测量。2.细胞更换培养液,对照组培养液含9,10-【~3H】棕榈酸,培养24h;PE组培养液含PE、9,10-【~3H】棕榈酸,培养24h;实验组培养液含PE、哌加他尼钠钠、9,10-【~3H】棕榈酸,培养24h,之后收集测量。
3.H9C2细胞的培养:H9C2细胞按5000/cm~2密度接种到培养瓶,培养基为10%胎牛血清DMEM培养液,每2天换液一次。细胞随机分为三组:对照组(n=10)、LPS组(n=10)和实验组(n=10),LPS组在细胞培养稳定后加LPS培养24h;实验组在细胞培养稳定后加LPS和哌加他尼钠钠培养24h,对照组正常换液。
4.RT-PCR法检测:分别从左室组织提取RNA,经逆转录反应得到cDNA,以APRT作为参照,通过RT-PCR技术检测ANF、PDK4等的表达。
5.免疫印迹检测:取H9C2细胞,提取蛋白,经过SDS-聚丙烯酰胺凝胶电泳(SDS-PAGE)分离、转膜、蛋白印记、ECL显色等步骤,检测VEGF、PPARβ的蛋白表达。
结果:
1.手术组心脏/体重比较对照组明显升高,心脏心肌肥大相关因子明显升高,药物组相关数据较手术组明显降低;
2.PE处理的新生大鼠心肌细胞蛋白质含量升高,心肌肥大相关因子表达增多,而这些都可以被VEGF抑制剂缓解;
3.PE处理的新生鼠心肌细胞脂肪酸氧化降低,而VEGF抑制剂可以缓解这种改变;
4.LPS处理的H9C2细胞VEGF表达增多,PPARβ表达降低,经VEGF抑制剂处理后VEGF表达减少,而PPARβ表达增多。
结论:
1.通过主动脉缩窄手术,成功建立了心肌肥大模型,为实验研究提供了可靠平台;
2.心肌肥大时VEGF表达增多,PPARβ表达减少,脂肪酸氧化减少;VEGF抑制剂可以使VEGF表达相对减少,PPARβ表达相对增多,脂肪酸氧化相对增多;
3.VEGF抑制剂可以促进心肌肥大时的脂肪酸氧化。
背景:
心肌肥大指心肌细胞的体积增大而数量不变,往往由于心脏长期后负荷过重及神经内分泌过度激活而引起。心肌肥大如果不能得到及时纠治,通常发展为慢性心力衰竭,进而导致死亡。尤其是左心室肥大,更容易增加心脏猝死、心律失常和心肌梗塞的风险。但目前研究结果显示,只有抗高血压治疗可以有效改善肥大心肌结构和功能上的改变。如果能够清楚心肌肥大的诱导因素、发展过程以及各种因子对心肌肥大的影响,我们就可以有的放矢,缓解甚至消除心肌肥大带来的种种不良后果。
VEGF-B于1996年首次被分离、克隆,其基因含有7个外显子,DNA长度约为4kb,位于染色体的11q13的位置。作为VEGF家族六种分子变异(VEGF-A,-B,-C,-D,-E和胎盘生长因子)之一,VEGF-B在组织中分布广泛,但在心肌、骨骼肌和血管平滑肌尤其多。大量研究已经证实VEGF-B对脑具有缺血性保护作用,但是VEGF-B促血管生成作用非常弱,实验证明通过病毒载体将VEGF-B转染到肌肉并不能有效刺激血管生成。此外,以敲除和过表达VEGF-B的小鼠作为实验对象研究VEGF-B在不同病理性血管生成模型中的作用显示,VEGF-B的缺失对受损皮肤、低氧肺、缺血性视网膜病变及缺血性四肢病变的血管生成没有影响,并且VEGF-B的过表达也不能增加受损皮肤和缺血性四肢病变的血管生成。而且,不同于其他VEGF,VEGF-B并不能增加血管通透性。VEGF-B包括两种亚型:VEGF-B_(167)和VEGF-B_(186),它们都可以和VEGFR-1和NP-1结合,而不能和促有丝分裂受体VEGFR-2和VEGFR-3结合发挥作用。
我们通过实验小鼠VEGF-B过表达来研究其在心肌肥大发生中的作用,为我们将来的临床药物治疗心肌肥大奠定良好的理论基础。
目的:
1.构建VEGF-B过表达动物模型;
2.构建主动脉缩窄可逆转动物模型;
3.构建心肌萎缩动物模型;
4.通过不同指标检测,探讨VEGF-B在心肌肥大过程中的作用。
方法:
1.VEGF-B过表达动物模型的建立:VEGF-B过表达小鼠,通过PCR基因型筛选得到VEGF-B+/+纯合子小鼠进行实验。
2.主动脉缩窄可逆转动物模型的建立:实验小鼠分为实验组(VEGF-B+/+,n=20),实验假手术组(VEGF-B+/+,n=20),对照组(野生型,n=20)和对照假手术组(野生型,n=20),年龄、性别配对。实验组和对照组小鼠异氟烷麻醉后气管插箭,并持续气管吸入异氟烷保持麻醉,仰卧位,胸骨上切迹纵行切口暴露主动脉弓、左颈动脉和无名动脉,在左颈动脉和无名动脉起始间用8-0线缩窄主动脉,术后缝合切口。术后4周,沿原手术切口进入,拆除结扎线。实验假手术组和对照假手术组,除结扎缩窄主动脉外,其他手术操作相同。
3.心肌萎缩动物模型的建立:实验小鼠分为实验组(VEGF-B+/+,n=12),实验假给药组(VEGF-B+/+,n=12),对照组(野生型,n=12)和对照假给药组(野生型,n=12),年龄、性别配对。实验组和对照组小鼠连续两周给予地塞米松皮下注射;实验假给药组和对照假给药组小鼠连续两周给予生理盐水皮下注射。
4.超声心动图检测:超声心动图检测:按照实验计划进行超声心动图检查,测定如下指标:心率(HR)、左室重量指数(LVMI)、左心室舒张期末内径(LVEDD)、左心室收缩期末内径(LVESD)、左室舒张末容积(LVEDV)、左室收缩末容积(LVSDV)、左心室射血分数(LVEF)、左心室短轴缩短率(LVFS)等。
5.血流动力学检测:按照实验计划,在主动脉缩窄前、缩窄后和解除缩窄后等不同时间点通过超声探头检测左、右颈动脉血流。
6.实时定量RT-PCR法检测:分别从主动脉缩窄模型心室肌组织提取RNA,经逆转录反应得到cDNA,以GAPDH作为参照,通过real-time PCR技术检测βMHCmRNA、BNP mRNA、SMA mRNA、TIMP1 mRNA、TIMP2 mRNA和MMP2 mRNA等的表达。
7.心肌组织病理学检查:动物处死后,进行组织取材、固定、脱水、透明、浸蜡、石蜡包埋、切片,常规HE染色、Masson三色染色、凝集素染色,观察心室壁厚度变化,观察、测量心肌细胞面积。
结果
1.主动脉缩窄模型LVM/BW、HW/BW、左心室舒张末期前壁和后壁厚度:对照假手术组未发生明显改变;实验假手术组保持上升趋势,并在第5周达到高峰;实验组和对照组持续上升,在第4周达到峰值,但前者幅度较后者明显,在解除主动脉缩窄后,LVM/BW、HW/BW开始逐渐下降,对照组下降到对照假手术组水平,实验组下降到实验假手术组水平。
2.主动脉缩窄模型左、右颈动脉血流动力学检测:实验组和对照组主动脉缩窄手术后左颈动脉血流减速,而右颈动脉血流加速,VR╱VL即刻上升;在术后第4周,VR/VL下降,对照组和实验组右颈动脉血流速度下降,但前者幅度更大;主动脉缩窄解除后第2周,实验组和对照组VR/VL下降到正常水平,但颈动脉血流速度并没∑恢复到主动脉缩窄前基础值。对照假手术组和实验假手术组血流动力学不受手术影响,后者VR/VL虽然没有改变,但颈动脉血流速度随时间延长而逐渐增加,并在第6周达到高峰,之后时间点无明显变化。
3.心肌组织病理切片显示主动脉缩窄模型心室壁厚度:对照假手术组无明显变化;实验假手术组心室壁逐渐增厚,在第5周达到最厚;实验组逐渐增厚,在第4周解除主动脉缩窄前达到最厚,此时厚度远高于其他组水平,缩窄解除后,心室壁厚度下降,在缩窄解除后第2周和第4周,心室壁厚度与实验假手术组相近;对照组术后也逐渐增厚,在第4周解除主动脉缩窄前达到最厚,此时厚度远高于对照假手术组,但低于实验组和实验假手术组,主动脉缩窄解除后,心室壁厚度有所下降,在缩窄解除后第2周和第4周,心室壁厚度与对照假手术组相近。
4.心肌组织病理切片显示主动脉缩窄模型心肌组织横断面肌束:在主动脉狭窄后第4周,心肌束直径:实验组＞实验假手术组＞对照组＞对照假手术组;解除主动脉狭窄后第4周,心肌束直径:实验组=实验假手术组＞对照组=对照假手术组。
5.主动脉缩窄模型心肌细胞面积:对照假手术组前后无明显变化;对照组在主动脉狭窄术后第4周达到高峰而且在解除主动脉狭窄后逐渐恢复到正常大小;实验假手术组逐渐增大,第6周时为最大值,之后无明显变化;实验组在第4周达到高峰,且其面积明显高于其他组,在解除主动脉狭窄后,心肌细胞面积逐渐缩小,2周后接近实验假手术组。
6.主动脉缩窄模型βMHC mRNA、BNP mRNA、SMA mRNA、TIMP1 mRNA、TIMP2 mRNA和MMP2 mRNA等的表达:趋势一致,实验组和对照组各mRNA表达在第4周达到峰值,在解除主动脉狭窄后第2周均降低。实验假手术组各mRNA表达逐渐增高,在第6周达到峰值。
7.心肌萎缩动物模型超声心动图检查:对照组AWD、PWD、AWS、PWS、LVM/BW、LVW/TL和HW/BW等各指标较其他各组值均小,而实验假给药组以上指标较其他各组值明显偏高。
8.心肌组织病理切片显示心肌萎缩动物模型心室壁厚度:对照假给药组和实验组心室肌无明显变化;对照组心室肌出现萎缩变薄;实验假给药组心室肌出现心肌肥厚。
9.心肌萎缩动物模型心肌细胞面积:实验组和对照假给药组无明显变化;对照组明显变小;而实验假给药组明显变大。
结论
1.通过主动脉缩窄手术和地塞米松注射,成功建立了动物模型,为实验研究提供了可靠平台;
2.主动脉缩窄动物模型中VEGF-B过表达促进心肌肥大,小鼠心肌在去除主动脉缩窄后肥大不能有效缓解;
3.在心肌萎缩动物模型中,VEGF-B过表达可以有效抵抗地塞米松诱导的心肌萎缩;
4.VEGF-B具有诱导心肌肥大的作用。
PARTⅠEffects of VEGF on fatty acid metabolism during cardiac hypertrophy
Background
Cardiac hypertrophy is a response of the heart to a wide range of extrinsic stimuli,such as arterial hypertension,valvular heart disease,myocardial infarction,and cardiomyopathy. But the response is not infinite and the heart function will be affected without removal of the etiopathogenisis.Sometimes,it could cause sudden death.Usually cardiac hypertrophy is associated with an increase in glucose utilization and a decrease in fatty acid oxidation.That the changes in intracellular substrate and metabolite levels in cardiomyocytes are a consequence or the reason for cardiac hypertrophy is still unknown. However,not some single factor plays the whole role in the development of cardiac hypertrophy.Defects in mitochondrial fatty acid oxidation enzymes cause childhood hypertrophic cardiomyopathy,and perturbation of fatty acid oxidation in animal models causes cardiac hypertrophy,demonstrating that substrate utilization is important in the pathogenesis of hypertrophy.
Vascular endothelial growth factor(VEGF) was first found by Ferrara and Gospodarowicz in 1989.It is a sub-family of growth factors,more specifically of platelet-derived growth factor family of cystine-knot growth factors.They are important signaling proteins involved in both vasculogenesis(the de novo formation of the embryonic circulatory system) and angiogenesis(the growth of blood vessels from pre-existing vasculature).It was reported that VEGF was involved in the process of myocardial hypertrophy.
Peroxisome proliferator-activated receptors(PPARs) are ligand-activated transcription factors that regulate the expression of genes involved in fatty acid uptake and oxidation, and inflammation.The PPAR subfamily consists of three subtypes,PPARα,PPARβ,and PPARγ.And it has been certified that PPARβis the most important subtype in cardiac cells and plays a prominent role in the regulation of cardiac lipid metabolism.
Till now,there is no report about the effects of VEGF on fatty acid oxidation during cardiac hypertrophy.Our research observed the effects of VEGF on PPARβand fatty acid oxidation during cardiac hypertrophy,exploring a new way for cardiac hypertrophy prevention and cure.
Objective
1.To establish a cardiac hypertrophy animal model,and culture Neonatal rat ventricular myocytes and H9C2 cells.
2.To observe the changes of protein expression and fatty acid oxidation in cardiac hypertrophy model.
3.To observe the influence of VEGF on PPARβand fatty acid oxidation.
Methods
1.Establish a cardiac hypertrophy animal model
Thirty male Wistar rats were randomly divided into 3 groups:control group(n=8), operation group(n=8) and medicine group(n=8).They were fed a standard diet for 7 days before the studies began.Pressure overload was induced by constriction of the abdominal aorta at the suprarenal level with 7-0 nylon strings.For the other two groups, sham operations were done.And the rats in the medicine group were given VEGF inhibitor,pegaptanib.Hearts were collected 15 days later.
2.Neonatal rat ventricular myocytes culture
Neonatal rat ventricular myocytes from 1 to 2 day old Wistar rats were prepared and cultured in Dulbecco's modified Eagle's medium containing 10%fetal bovine serum. Cells were randomly divided into 3 groups:control group(n=10),PE group(n=10) and medicine group(n=10).Cells of PE group were cultured with PE(phenylephrine) and cells of medicine group were culture with PE and pegaptanib.Then the cells were treated like this:1.Cells of PE group were cultured with PE and[~3H]leuCine and cells of medicine group were culture with PE,pegaptanib and[~3H]leuCine for 24h.Then the protein was isolated and tested.2.Cells of PE group were cultured with PE and 9,10-[~3H]palmitate and cells of medicine group were culture with PE,pegaptanib and 9,10-[~3H]palmitate for 24h.Then the results were got.
3.H9C2 cells culture
H9C2 cells culture were cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum.Cells were randomly divided into 3 groups:control group(n=10), LPS group(n=10) and medicine group(n=10).Cells of LPS group were cultured with LPS and cells of medicine group were cultured with LPS and pegaptanib.
4.RT-PCR
The RNA was extracted from ventricles of different group rats.The mRNA expressions of ANF and PDK4 were determined by RT-PCR.
5.Western-blot analysis
Western-blot analysis was used to determine the protein expression of VEGF and PPARβ.
Results
1.Operation group showed a higher HW/BW and more ANF expression than control group,while the data of the medicine group were lower than those of the operation group.
2.PE induced the ANF expression and its effect was reversed by VEGF inhibitor, pegaptanib.
3.PE decreased neonatal rat cardiomyocytes fatty acid oxidation,and its effect was reversed by VEGF inhibitor,pegaptanib.
4.LPS increased the expression of VEGF and decreased the expression of PPARβ,and pegaptanib decreased the expression of VEGF and increased the expression of PPARβ.
Conclusion
1.A cardiac hypertrophy animal model was established by 15 days of constriction of the abdominal aorta in male Wistar rats.
2.VEGF expression was increased,PPARβexpression was decreased,and fatty acid oxidation was decreased during cardiac hypertrophy.While,all the results were reversed by VEGF inhibitor,pegaptanib.
3.VEGF inhibitor can promote the fatty acid oxidation of hypertrophic cardiomyocytes.
PARTⅡEffects of VEGF-B on inducing cardiac hypertrophy
Background
Pathologic cardiac hypertrophy develops in response to increases in afterload and represents a common intermediary in the development of heart failure.Left ventricular hypertrophy is an independent risk factor for several adverse outcomes,including cardiac mortality,arrhythmias,and myocardial infarction.Results from numerous studies suggest that reducing heart mass in patients with pathologic cardiac hypertrophy may reduce morbidity and mortality and improves patient outcomes.However,the only treatments currently proven to reverse both structural and functional cardiac abnormalities associated with pathologic cardiac hypertrophy are anti-hypertensive therapies and aortic valve replacement(for aortic stenosis),both of which have a limited success rate. Understanding the underlying processes regulating plasticity of the heart will allow us to identify specific pathways against which to target new therapies and may improve the long-term outcomes of patients with pathologic cardiac hypertrophy.
Vascular endothelial growth factor(VEGF) was first found by Ferrara and Gospodarowicz in 1989.Members of the vascular endothelial growth factor(VEGF) family,currently comprising 6 mammalian proteins,are major regulators of blood and lymphatic vessel development and growth.VEGF is essential for vasculogenesis and angiogenesis.VEGF-B has a wide tissue distribution,being most abundant in the myocardium,skeletal and vascular smooth muscle.VEGF-B has also been implicated in protecting the brain from ischemic injury.However,the ability of VEGF-B to stimulate angiogenesis directly is poor in many tissues.And role of VEGF-B was studied in various models of pathological angiogenesis using mice lacking VEGF-B or overexpressing VEGF-B,which suggested that VEGF-B having a relatively restricted angiogenic activity in the ischemic heart.VEGF-B did not stimulate vessel growth when delivered into muscle or periadventitial tissue via adenoviral vectors.On the contrary,VEGF-B overexpressed in endothelial cells of transgenic mice was able to potentiate,rather than initiate,angiogenesis.And unlike VEGF,VEGF-B did not increase vascular permeability. VEGF-B exists as 2 isoforms,VEGF-B167 and VEGF-B186,generated by alternative splicing.Both isoforms bind to VEGF receptor(VEGFR)-1 and neuropilin-1 but not to the major mitogenic endothelial cell receptors VEGFR-2 or VEGFR-3.
Here we have studied the effects of VEGF-B on inducing cardiac hypertrophy with mice overexpressing VEGF-B,exploring a new way for cardiac hypertrophy prevention and cure.
Objective
1.To establish a VEGF-B overexpression animal model.
2.To establish a cardiac hypertrophy reversal animal model.
3.To establish a cardiac atrophy animal model.
4.To explore the effects of VEGF-B on inducing cardiac hypertrophy by different index examination.
Methods
1.Establishment of the VEGF-B overexpression animal model VEGF-B overexpression mice were gift from another lab.We got the VEGF-B+/+ homozygote mice by mating and PCR genotyping.
2.Establishment of the cardiac hypertrophy reversal animal model Forty VEGF-B+/+ mice were randomly divided into 2 groups:experiment group(n=20) and experiment-sham group(n=20);and Forty wild type mice were randomly divided into 2 groups:control group(n=20) and control-sham group(n=20).Mice of experiment group and control groups were anesthetized,and a longitudinal incision was made at the level of the suprasternal notch,allowing for visualization of the aortic arch,left carotid, and innominate artery.An 8-0 suture was used to encircle the aorta between the origin of the left carotid and the innominate arteries.One end of the suture was cut short while the other was left longer,lying on top of the pretracheal muscle and underneath the skin for easy future removal according to the schedule.For the other two groups,sham operations were done.
3.Establishment of the cardiac atrophy animal model VEGF-B+/+ mice were randomly divided into 2 groups:experiment group(n=12) and experiment-sham group(n=12);and wild type mice were randomly divided into 2 groups: control group(n=12) and control-sham group(n=12).Mice of experiment group and control groups were given dexamethasone subcutaneous injection daily for 2 weeks;and the mice of the other two groups were given saline vehicle subcutaneous injection daily for 2 weeks.
4.Echocardiogram examination
According to the schedule,transthoracic echocardiogram was performed.Mice were placed supine and the anterior chest wall was shaved.Echocardiograms were performed. Conventional images included 2-dimensional,M-mode,and continuous wave and pulsed Doppler images.
5.Hemodynamic assessment of aorta flow
To assess the aortic constriction after TAC and TAC reversal,right and left carotid artery flow was assessed using a 20 MHz probe driven by a high frequency pulsed Doppler signal processing workstation.
6.Real-time RT-PCR
The RNA was extracted from ventricles of different group rats.The mRNA expressions of BNP andβMHC,etc.were determined by real-time RT-PCR.
7.Histology and staining
Hearts were perfused and processed for histology and stained with H&E or lectin.Cell area was determined.
Results
1.The HW/BW,LVM/BW and thickness of ventricular walls in the cardiac hypertrophy reversal animal model:no change happened on control-sham group;values of experiment group were higher than those of control group and reached their peak at 4W;the values of experiment-sham group reached their peak at 1WR.
2.Hemodynamic assessment of aorta flow:the VR/VL of control group and experiment group increased after TAC and decreased after TAC reveal;the VR/VL of control-sham group and experiment-sham group did not change.
3.Histology showing the thickness of the ventricles in the cardiac hypertrophy reversal animal model:no change happened on control-sham group;the value of experiment group was higher than that of control group and reached its peak at 4W;the value of experiment-sham group reached its peak at 1WR.
4.Histology showing cross section of muscle bundles:at 4W,experiment group＞experiment-sham group＞control-sham group＞control group;at 4WR,experiment group=experiment-sham group＞control-sham group=control group.
5.Cardiomyocyte area in the cardiac hypertrophy reversal animal model:no change happened on control-sham group;the value of experiment group was higher than that of control group and reached its peak at 4W;the value of experiment-sham group reached its peak at 2WR.
6.βMHC mRNA,BNP mRNA,SMA mRNA,TIMP1 mRNA,TIMP2 mRNA and MMP2 mRNA expression:the values of experiment group and control group reached their peak at 4W,and the values of experiment-sham group reached their peak at 2WR.
7.AWDA,PWD,AWS,PWS,LVM/BW,LVW/TL and HW/BW in the atrophy model: the values of control group were smaller than the others,and the values of experiment-sham group were larger than the others.
8.Histology showing the ventricle thickness in the atrophy model:experiment group and control-sham group had no change;control group got thinner ones,and experiment-sham group got thicker ones.
9.Cardiomyocyte area in the atrophy model:experiment group and control-sham group had no change;control group got smaller ones,and experiment-sham group got larger ones.
Conclusion
1.The models of VEGF-B overexpression,cardiac hypertrophy reversal,and cardiac atrophy were successfully established.
2.In the cardiac hypertrophy reversal animal model,VEGF-B overexpression induced cardiac hypertrophy and its effect was attenuated little after cardiac hypertrophy reversal.
3.In the cardiac atrophy animal model,VEGF-B overexpression neutralized the atrophy inducing effect of dexamethasone.
4.VEGF-B can induce cardiac hypertrophy.
引文
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