Role of cellular paracrine in the mechanism of cardiomyocyte hypertrophy induced by stretch

AIM: To investigate the role of cellular paracrine in the mechanism of cardiomyocyte hypertrophy induced by stretch. METHODS: [³H]-leu incorporation into cultured cardiomyocytes was measured when stimulated by conditioned-media of myocardial fibroblast and microvascular endothelial cell after stretch. RESULTS: [³H]-leu incorporation rate were both elevated significantly stimulated by conditioned-media of myocardial fibroblast and microvascular endothelial cell. And angiotensin II and endothelin of conditioned-media of myocardial fibroblast and microvascular endothelial cell were also elevated significantly. And [³H]-leu incorporation rate were inhibited significantly when the specific angiotensin II and endothelin receptor antagonist losartan(1μmol/L) and BQ123(1μmol/L) were added. [³H]-leu incorporation rate were inhibited over 80% when losartan(1μmol/L) and BQ123(1μmol/L) were added together.CONCLUSION: The activation of myocardial fibroblast and microvascular endothelial cell endocrine stimulated by stretch play a role through paracrine in the pathogenesis of pressure-overload heart hypertrophy.     

Inhibitory effect of hydrogen sulfide (H2S) on cultured rat aortic smooth muscle cells

AIM:To explore the effects of hydrogen sulfide (H₂S) on proliferation of vascular smooth muscle cells (VSMC) stimulated by endothelin (ET-1, 10^-7mol/L) and mitrogen-activated protein kinase (MAPK) activity in VSMCs.METHODS:Cultured VSMCs were divided into six groups: (1) control group, (2) serum group, (3) endothelin group, (4) NaHS groups, (5) serum+NaHS group, and (6) endothelin+NaHS group. VSMC proliferation was measured by[³H]-TdR incorporation and MAPK activity in VSMC was determined by radioactivity assay.RESULTS:ET-1 increased VSMC[³H]-TdR incorporation by 2.39 times (P＜0.01) and MAPK activity by 1.62 times(P＜0.01), as compared with control. H₂S (5×10^-5-5×10^-4mol/L) decreased VSMC[³H]-TdR incorporation and MAPK activity by 16.8%-37.4% and 7.4%-33.6%, respectively (P<0.05 or P＜0.01).CONCLUSION:This study demonstrates that H₂S inhibits ET-1-induced proliferation of VSMC, which might be mediated by the inhibition of MAPK.     

Yangxue qingnao-containing serum inhibits rat vascular smooth muscle cell proliferation induced by lysophosphatidic acid

AIM: To observe the effects of Yangxue qingnao-containing serum on rat vascular smooth muscle cell (VSMC) proliferation induced by lysophosphatidic acid (LPA). METHODS: The [³H]-TdR incorporation and mitogen-activated protein kinasc (MAPK) activity were measured in cultured VSMC. End product of lipid peroxidation-MDA levels were also detected. RESULTS: 1×10^－9,1×10^－8 and 1×10^－7 mol/L LPA enhanced the cultured VSMC [³H]-TdR incorporation, increased MAPK activity and MDA content in a concentration-dependent manner. 5％, 10％ and 15％ Yangxue qingnao-containing serum concentration-dependently inhibited the increase in VSMC [³H]-TdR incorporation, MAPK activity and MDA content induced by LPA. CONCLUSIONS: LPA has a stimulating effect on VSMC proliferation. The LPA-induced intracellular signal transduction may be related to MAPK activity. Yangxue-qingnao can efficiently inhibit LPA -induced VSMC proliferation,MAPK activity and lipid peroxidation.     

Effects of β3 integrin on adhesion and migration of vascular smooth muscle cells induced by growth factor

AIM: To investigate the effect of platelet-derived growth factor (PDGF) on β₃ integrin gene expression and the role of β₃ integrin on adhesion, migration and proliferation of vascular smooth muscle cells (VSMC) induced by PDGF. METHODS: β₃ integxin gene expression was detected by RT-PCr. After β₃ integrin extracellular do-main was blocks, VSMC adhesio, migration and proliferation were measured by adhesion assay awound-culture model an [³H]-TSR incorporation respectively.RESULTS: After the interaction between β₃ integrin and extracellular matrix was blocked, VSMC proliferation was inhibited in some degree and the rate of [³H]-TdR incorporation into VSMC decreased 39%. The cell adhesion and migration were significantly inhibited when 10 mg/L anti-β₃ integrin antibody was added (P＜0.05). When VSMC were treated by PDGF for 6 hours, the expression of β₃ integrin gene was 87% higher than that of control. CONCLUSION: PDGF significantly induces expression of β₃ integrin gene in VSMC, and the interaction between β₃ integrin and ECM protein may play an important role in VSMC adhesion and migration.     

Roles of ERKs and intracellular free calcium in cardiomyocyte hypertrophic response induced by endothelin-1

AIM: To study the roles and mechanisms of ERKs and intracellular free calcium in cardiomyocyte hypertrophic response induced by endothelin-1(ET-1). METHODS: (1) Neonatal rat cardiomyocyte hypertrophic response was assayed by measuring cell surface area and protein content; (2) ERKs activity was determined by Whatman Paper Filter method; (3) Intracellular free calcium concentration ([Ca²⁺]i) was measured using Fura-2/AM as a fluorescent indicator. RESULTS:(1)ET-1 could increase total protein production,surface area,ERKs activity and[Ca²⁺]i in cultured cardiomyocyte in dose-dependent manner at concentrations ranging from 10^-9to 10^-7mol/L.And this effect could be abolished by BQ123,an antagonist of ETA receptor,partly inhibited by PTX,but not by BQ788,an antagonist of ETB receptor.(2)The activation of ERKs and the increase of[Ca²⁺]i induced by ET-1 were obviously in hibited by PD98059,a selective ERKs kinase inhibitor,and nifedipine,a calcium channel blocker,respectively.Both antagonists partialy inhibited ET-1-stimulated cardiomyocyte hypertrophic response.(3)Staurosporine,a selective PKC inhibitor,could inhibit ET-1-stimulated cardiomyocyte hypertrophic response and increase of[Ca²⁺]i,but not af ect the activation of ERKs.CONCLUSION: Cardiomyocyte hypertrophic response induced by ET-1 is mediated by ET_A receptor coupled to PTX-sensitive G-protein, which involves at least two signalling pathways: PKC-mediated increase of [Ca²⁺]i , and PKC-independent activation of ERKs.     

Effects of inhibiting myosin light chain kinase on endothelin-1 induced proliferation and apoptosis of pulmonary arterial smooth muscle cells in rats

AIM: To investigate the effect of inhibiting myosin light chain kinase(MLCK) on endothelin-1(ET-1) induced proliferation and apoptosis of rat pulmonary artery smooth muscle cells(PASMCs). METHODS: Rat PASMCs were cultured and stimulated with ET-1. The cells were randomly divided into control group, ET-1 group and ET-1+MLCK inhibitor group(ET-1+M). Western blotting, MTT assay, [³H]-TdR incorporation and flow cytometry were employed to test the expression of myosin light chain(MLC) and MLCK, cell proliferation, cell cycle and apoptotic rate of PASMCs,respectively. The phosphorylation of MLC was determined by glycerol-PAGE coupled with Western blotting. RESULTS: Compared with control group, the protein expression of MLCK and MLC phosphorylation significantly enhanced after ET-1 stimulation. ET-1 markedly induced the proliferation and decreased the percentage of apoptotic rate in the PASMCs. However, pretreatment with ML-7, a MLCK inhibitor, significantly reversed the above effects induced by ET-1. CONCLUSION: MLCK inhibitor effectively inhibits the ET-1-induced proliferation and the cell cycle progression.     

Effects of adrenomedullin on proliferation of vascular smooth muscle cells induced by urotensin Ⅱ

AIM:To observe the effect of adrenomedullin(ADM)on proliferation of vascular smooth muscle cells(VSMC) induced by urotensin Ⅱ(UⅡ). METHODS:DNA synthesis of cultured rat aortic VSMC was measured by [³H]-TdR incorporation. The activities of mitogen activated protein kinase(MAPK) were determined by isotope tagged with [γ-³²P]-ATP. RESULTS:UⅡ(10^-8mol/L) significantly increased [³H]-TdR incorporation of VSMC and MAPK activities by 38%(P＜0.05) and 260%(P＜0.01) respectively compared with control group. Compared with UⅡ group, 10^-10,10^-9,10^-8mol/L ADM decreased [³H]-TdR incorporation of VSMC by 7%(P＞0.05), 32%(P＜0.05)and 41%(P＜0.01),respectively, and diminished MAPK activities by 24%(P＞0.05), 32%(P＜0.05)and 36%(P＜0.05),respectively. CONCLUSION:ADM inhibits proliferation of VSMC induced by urotensin Ⅱ through inhibiting MAPK activation.     

Effect of caveolin-1 and ERK1/2 on 17β-estradiol-induced inhibition of VSMC proliferation

AIM: To investigate the effect of caveolin-1 and phosphorylation of ERK1/2 on 17β-estradiol (E2) induced inhibition of vascular smooth muscle cells (VSMCs). METHODS: The proliferation in cultured VSMCs was determined by using ［3H］-thymidine incorporation. The expressions of caveolin-1, MKP-1 and ERK1/2 phosphorylation were measured by Western blotting. The expression of caveolin-1 mRNA was measured by RT-PCR. RESULTS: Exposed to fetal calf serum (FCS) for 24 h, the increase in proliferation of VSMCs was detected by ［3H］-thymidine incorporation. Pretreatment with various concentrations of E2 for 24 h inhibited VSMC proliferation induced by FCS. The results of Western blotting and RT-PCR showed that pretreated with 17β-estradiol for 24 h reserved the decrease in caveolin-1 induced by FCS. Western blotting results further proved that the expression of MKP-1 was significantly increased and the expression of ERK1/2 phosphorylation was decreased after incubated with 17β-estradiol. CONCLUSION: 17β-estradiol increases caveolin-1 and MKP-1 expressions, and decreases ERK1/2 phosphorylation, leading to the inhibition of VSMC proliferation.     

Bio-effects of salusins on isolated rat heart and neonatal cardiomyocytes

AIM: To investigate the bio-effects of salusins on rat heart and cardiomyocytes. METHODS: The cardiac function was determined by multipurpose polygraph in isolated rat heart treated with various concentrations of salusin-α or salusin-β.[⁴⁵Ca²⁺] and[³H]-Leu incorporation were determined in cultured neonatal rat cardiomyocytes with β-liquid scintillation counter. RESULTS: 10^-12-10^-7mol/L salusin-α and salusin-β had no effects on isolated rat cardiac function. However, salusin-α and salusin-β stimulated uptake and[³H]-Leu incorporation. The [⁴⁵Ca²⁺] uptake induced by salusins were inhibited by nicardipine, and were synergistically increased by endothelin-1. The[³H]-Leu incorporation induced by salusin-α and salusin-β was inhibited by nicardipine, FK506 (a special inhibitor of carcineulin), PD₉₈₀₅₉ (inhibitor of MAPK) and chelerthine (inhibitor of PKC). The effects of salusin-β[⁴⁵Ca²⁺] on uptake was stronger than those of salusin-α. But there were no statistical difference in[³H]-Leu incorporation between salusin-α and salusin-β. CONCLUSIONS: Salusin-α and salusin-β did not affect directly cardiac function in rat hearts. But salusins improved calcium uptake and protein synthesize in neonatal rat cardiomyocytes. Those effects of salusins were related with calcium channel, carcinuelin, MAPK and PKC signal pathways. Salusins may be the regulatory factors for myocardium growth and hypertrophy.     

Inhibitory effect of Salidroside on the proliferation of rabbit pulmonary artery smooth muscle cells under hypoxia

AIM: To investigate the effect of Salidroside on the proliferation, DNA synthesis, intracellular Ca²⁺ content of rabbit PASMC (pulmonary artery smooth muscle cells) under hypoxia. METHODS: Techniques of cell culture, MTT test, [³H][³H][³H]-TdR incorporation, fluo-3 and confocal laser scanning microscopy were used. RESULTS: The A value of MTT and [³H][³H]-TdR incorporation of PASMC increased significantly by 62% (P＜0.05) and 138% (P＜0.01) after 24 h hypoxia. Salidroside (32×10^-5 mol/L) inhibited the action of hypoxia on the proliferation of PASMC, the A value of MTT and [³H][³H]-TdR incorporation declined significantly by 29% (P＜0.05) and 37% (P＜0.01) compared with hypoxia group. A calcium channel blocker, verapamil could also inhibit the accelerative effect of hypoxia on the proliferation of PASMC. The intracelluler Ca²⁺ content of PASMC raised markedly under hypoxia, but the effect of hypoxia on the intracelluler Ca²⁺ content could be inhibited by Salidroside. CONCLUSION: Salidroside inhibited the proliferation, DNA synthesis of PASMC induced by hypoxia. The inhibitory action of Salidroside on the increase in intracellular Ca²⁺ concentration under hypoxia might be one of the mechenisms.     

Effects of thyroid hormone on the myosin heavy chain mRNA expression in cardiac myocytes induced by angiotensin Ⅱ

AIM: To study the effect of thyroid hormone on the expressional change of myosin heavy chain(MHC) gene in cardiomyocyte induced by angiotensinⅡ(AngⅡ) and its potential mechanism. METHODS: Cardiac myocyte was cultured according to the method of Simpson. 10^-8 mol/L T₃ and 10^-7 mol/L AngⅡ were added to the culture medium, respectively or synchronously. After 48 h, the expression of α and β-MHC mRNA in myocytes were detected by RT-PCR. The protein kinase C activation were detected by PepTag non-radioactive PKC assay. The incorporation of -Leucine and [³H]-thymine to test the protein and DNA synthesis in myocytes were also performed. RESULTS: AngⅡalone increased the incorporation of [³H]-Leucine of myocytes while it had no effect on the incorporation of [³H]-thy mine. The expression of β-MHC mRNA was increased and the expression of α-MHC mRNA was decreased significantly at the condition of AngⅡ. The enhanced PKC activation was induced by AngⅡalso. When AngⅡand T₃ were added to the culture medium synchronously, though the incorporation of [³H]-leucine and [³H]-thymine were not changed compared with AngⅡ treated alone. The α-MHC mRNA expression was increased and the β-MHC mRNA expression was decreased significantly. The PKC activation of the myocytes also was decreased. CONCLUSIONS: T₃ inhibited the expressional change of myosin heavy chain gene in cardiac myocytes induced by AngⅡ. The effect of T₃ on the change of PKC activation in cardiac myocytes may be one of its mechanisms.     

Inhibitory effects of Lobelia Chinensis Lour alkaloid on the proliferation of human umbilical artery vascular smooth muscle induced by endothelin-1

AIM: To investigate the effects of Lobelia Chinensis Lour Alkaloid (LCLA) on the proliferation of cultured vascular smooth muscle cells (VSMC) induced by ET-1. METHODS: Human umbilical artery VSMC was cultured and divided into five groups: ET group, ET+LCLA group, ET+BQ-123 group，ET+ staurosporine （ST） group and control group. The cell proliferation activity was subsequently quantified by cell counting kit-8 (CCK-8) and ［3H］-TdR incorporation. Flow cytometry was used to examine cell cycle. Quantitative immunohistochemical technique was used to investigate the expression of proliferating cell nuclear antigen (PCNA) and confocal microscope was used to measure the fluorescent intensity of Ca2+. Cytotoxicity was measured by Trypan blue exclusion and LDH colorimetry tests. RESULTS: BQ-123 (10-6mol/L), ST (10-7mol/L) and LCLA (100, 200 and 400 mg/L) inhibited the increase in cell number, ［3H］-TdR incorporation, the percentage of the S phase and markedly decreased the expression of PCNA and fluorescent intensity of Ca2+ in response to ET-1 of VSMC (P<0.05). CONCLUSION: LCLA (100-400 mg/L) inhibits ET-1-induced proliferation of VSMC in a dose-dependent manner and the anti-proliferative effect is realized by reducing the Ca2+ concentration in VSMC.     

Signal mechanism of endothelin-1-mediated activation of airway fibroblasts induced by injured airway epithelial cells

AIM: To explore the effects of p38 mitogen-activated protein kinases (MAPK) and phosphoinositide 3-kinases (PI3K)/Akt on interleukin (IL)-6, the endothelin (ET)-1-mediated process of airway fibroblast activation induced by injured human bronchial epithelial cells (HBE). METHODS: Human primary cultured airway fibroblasts were co-cultured with HBE pre-treated with or without poly-L-arginine (PLA). The procedure was also performed in the presence or absence of p38 MAPK selective inhibitor SB203580, PI3K selective inhibitor LY294002 or ETA receptor blocker BQ123, respectively. Immunostaining, Western blotting or ELISA were used for detecting α-smooth muscle actin (α-SMA) expression, the activities of p38 MAPK and Akt in fibroblasts or IL-6 levels in supernatants of fibroblasts. In addition, fibroblasts were mixed with soluble collagen and cultured with HBE treated as the same mentioned above, the gel contraction was measured by serial area measurements. RESULTS: ET-1 and IL-6 levels ［(13.69±1.36) ng/L, (56.7±10.7) ng/L］ in the supernatants of fibroblasts cultured with injured HBE were significantly higher than those in the supernatants of fibroblasts cultured with HBE ［(3.79±0.64) ng/L, (15.5±3.2) ng/L］. BQ123, SB203580 or LY294002 decreased IL-6 levels ［(27.2±3.1) ng/L, (31.5±3.6) ng/L, (41.3±3.2) ng/L］ differently in the supernatants of fibroblasts induced by injured HBE. Activation of p38 MAPK preceded Akt in fibroblasts cultured with injured HBE. BQ123 reduced the phosphorylation levels of p38 MAPK and Akt. SB203580 concentration-dependently attenuated Akt phosphorylation, while LY294002 had little effect on p38 MAPK phosphorylation. Fibroblasts expressed more α-SMA after cultured with injured HBE and showed significant increase in the gel contraction compared to fibroblasts cultured with HBE ［percentage of gel contraction: (61.2±2.7)% vs (15.4±7.3)%］, all these effects were diminished or inhibited by BQ123, SB203580 or LY294002. Furthermore, the effects of BQ123 and SB203580 on decreased gel contraction were stronger than the effect of LY294002. CONCLUSION: ET-1 exerts a key role in the airway fibroblasts activation induced by injured HBE through activating p38 MAPK, PI3K/Akt signaling and promoting IL-6 expression.     

Effects of three kinds of calcium activator on the proliferation of cultured vascular smooth muscle cells in rats

AIM: To investigate the effects of intracellular free calcium ([Ca²⁺]i) from different resources on the proliferation mediated by mitogen activated protein kinase (MAPK) in vascular smooth muscle cells (VSMCs). METHODS: Cultured VSMCs were used in all experiments. Calcium influx was stimulated by angiotension Ⅱ(Ang Ⅱ). The release of intracellular calcium stores was induced by inositol trisphosphate (IP₃) and ryanodine (RY). MAPK activity was measured by [γ-³²P]-ATP incorporation MAPK protein expression by western blot, VSMCs proliferation by [³H]-Leucine ([³H]-Leu) and [³H]-Thymidine ([³H]-TdR) incorporation. RESULTS: Compared to the control VSMCs, Ang Ⅱ, IP₃ and RY significantly increased [Ca²⁺]i concentration activity of MAPK and its protein content in VSMCs. The promotion of [³H]-Leu and [³H]-TdR incorporation in VSMCs was also observed (P<0.01). CONCLUSION: The study indicated that calcium activator-induced increase in the activity and protein content of MAPK was involved in the proliferation of VSMCs, which was closely related to the [Ca²⁺]i concentration but independent to its origin.     

Effects of Bene Jones protein and TGF-β1 on the proliferation of rat renal proximal tubular cells in vitro

AIM:To study the effect of Bene Jones protein (BJP) from multiple myeloma(MM) patient and TGF-β₁ on cultured renal proximal tubular cell(PTC) proliferation.METHODS:[H³]TdR incorporation was used to study the effect of λBJP and TGF-β₁ on cultured rat NRK.52E PTC proliferation, the expression of TGF-β₁ in the supernatant of PTC cultured with BJP was assessed with ELISA.RESULTS:① [H³]TdR incorporation of PTC was inhibited by BJP in a dose-dependent manner, when co-cultured with 100-800 μmol/L BJP and 2.0 μg/L TGF-β₁, the [H³]TdR incorporation was lower than that of BJP alone, especially when BJP≥400 μmol/L;②The expression of TGF-β₁ in the supernatant of PTC cultured with BJP was increased, especially when BJP≥400 μmol/L(P＜0.05);③ The [H³]TdR incorporation of PTC was also inhibited by exogenous TGF-β₁ in a dose-dependent manner.CONCLUSION:λBJP has antiproliferative effect on rat PTC in vitro, The effect is related with stimulating the PTC to produce excessive TGF-β₁, which also has antiproliferative effect on PTC in some degree.     

Cyclosporine A suppresses the hypertrophic effect of neuropeptide Y in rat cardiomyocytes

AIM:To investigate the effect of cyclosporine A on rat cardiomyocyte hypertrophy caused by neuropeptide Y (NPY).METHODS:Cardiomyocytes of neonatal Wistar rats were cultured with NPY or NPY together with CsA. For assessing protein synthesis rate and c-jun mRNA expression in cardiomyocytes, the methods of [³H]-Leu incorporation and RT-PCR were used.RESULTS:(1) [³H]-Leu incorporation in cardiomyocytes: [³H]-Leu incorporation in NPY (10 nmol/L) group was higher than that in control group, but there were no distinct changes between two groups. To compare with control group, [³H]-Leu incorporation in NPY (100 nmol/L) group were increased significantly (P＜0.05). There was no significant change between control group and CsA group; (2) c-jun mRNA expression in cardiomyocytes: RT-PCR production of c-jun mRNA in NPY group was enhanced considerably compared with CsA group and control group (P＜0.01). There was no significant change between CsA group and control group.CONCLUSIONS:NPY can induce cardiomyocyte hypertrophy. Cyclosporine A (inhibitor of CaN) can blunt the effect of NPY, suggesting that the Ca²⁺/CaM-dependent calcineurin (CaN) signaling pathway plays an important role in it.     

The synergistic effect of endothelin-1 and basic fibroblast growth factor on rat vascular smooth muscle cell proliferation

AIM: The synergistic effect of basic fibroblast growth factor (bFGF) and endothelin-1 (ET-1) on rat aortic vascular smooth muscle cells (VSMC) proliferation was observed. The possible mechanism of the synergism was also investigated. METHODS: BrdU incorporation and cell counting method were adopted to value the pro-proliferative effect of VSMC. Western blotting was used to observe the variation of bFGF and FGFR-1 isoforms expression. RESULTS: bFGF and ET-1 could promote VSMC proliferation separately, and synergistically in combination. The synergism was dose- and time-dependent. ET-1 increased all the three bFGF isoforms and FGFR-1 protein level in dose- and time-dependent manner. In addition, after exhaustion of intracellular PKC, the upregulation effects of ET-1 on bFGF and FGFR-1 expressions in VSMC both inclined. CONCLUSION: bFGF and ET-1 had synergistic effect on VSMC proliferation. ET-1 may increase the responsiveness of VSMC to bFGF through modulation of bFGF isoforms together with FGFR-1, which was PKC-dependent.     

Effect of trichosanthes injection on expression of proliferating cell nuclear antigen of vascular smooth muscle cell in rabbit

AIM: To observe the effect of thichosanthes injection on the expression of proliferating cell nuclear antigen (PCNA) of vascular smooth muscle cell (SMC). METHODS: The expression of PCNA of cultured rabbit aortic SMC was examined with LSAB immunohistochemical technique, and [³H]-thymidine( [³H]-TdR) incorporation data of SMC and the contents of superoxide dismutase (SOD), lipid peroxide (LPO), prostacyclin (PGI₂) and cyclic AMP (cAMP) in medium were simultaneously determined. RESULTS: Thichosanthes injection has an effects of increasing SOD activity, decreasing LPO, elevating PGI₂ and cAMP, reducing [³H]-TdR incorporation and expression of PCNA (all P＜0.05,P＜0.01). CONCLUSION: Thichosanthes could inhibit SMC proliferation.     

Taurine attenuated β-glycerophosphate-stimulated calcification in cultured rat vascular smooth muscle cells

AIM: To investigate the effect of taurine on calcification of vascular smooth muscle cells (VSMCs).METHODS: Calcified VSMCs of rat in vitro were induced by β-glycerophosphate. Cellular calcium content, alkaline phosphatase(ALP) activities and [⁴⁵Ca]accumulation were measured. DNA synthesis were evaluated by [³H]-thymidine ( [³H]-TdR) incorporation. RESULTS: Calcium content, ALP activities and [⁴⁵Ca]uptake of calcified VSMCs stimulated by taurine (5-20 mmol/L) were greatly decreased in a concentration-dependent manner as compared with calcified group (P＜0.01). Taurine also inhibited the proliferation of calcified cells in a concentration-dependent manner. Cell countingz, [³H]-TdR incorporation of calcified cells stimulated by taurine were greatly decreased as compared with calcified VSMCs (P＜0.01). CONCLUSION: It was demonstrated that calcification of VSMCs may be alleviated by taurine.     

番茄E8启动子乙烯应答元件克隆及DNA序列分析

E8启动子是常用的番茄果实特异表达启动子之一，是指番茄E8基因5’侧翼近2．2kb的DNA序列。前人的研究表明，E8基因5’侧翼-2181～-1088区段的删除使E8基因表达量大幅度下降(仅为完整E8启动子的1／10)，同时该区段还是E8基因对乙烯应答的充分必要区域；这说明了该区段是E8基因表达调控的重要元件。