血管平滑肌细胞增殖及分泌内皮素水平与氯沙坦和依拉普利的影响

目的:观察血管紧张素ⅡAT1受体阻滞剂氯沙坦及转换酶抑制剂依拉普利对培养的血管平滑肌细胞增殖的抑制作用及对血管平滑肌细胞分泌内皮素水平的影响。方法:实验于2004-03/11在华中科技大学生命学院生物物理与生物化学研究所实验室及武汉市七医院检验科完成。取大白鼠腹主动脉平滑肌细胞,用贴块法进行血管平滑肌细胞原代培养,进行消化传代后,取生长状态良好的3～6代血管平滑肌细胞,分别用含0.1,1.0,10,100μmol/L不同浓度的氯沙坦(氯沙坦组)和依拉普利(依拉普利组)的培养液培养,测定细胞倍增时间(TD=t犤log2/(logNt-logN0)犦,TD:细胞倍增时间,t:培养时间,No:接种后的细胞数,Nt:培养t小时后的细胞数),进行细胞增殖核抗原免疫组织化学检测,并计算增殖指数(增殖指数=增殖细胞核抗原阳性细胞核个数/400)。用均相竞争放射免疫分析法测定血管平滑肌细胞上清液内皮素-1的含量。结果:①培养的血管平滑肌细胞倍增时间:随氯沙坦和依拉普利浓度的逐渐增加,血管平滑肌细胞倍增时间逐渐延长(P<0.01),两组比较差异无显著性意义(P>0.05)。②增殖指数:氯沙坦组和依拉普利组增殖指数均显著降低(P<0.05或P<0.01),且呈剂量依赖性,两组间比较差异无显著性意义(P>0.05)。③培养的血管平滑肌细胞上清液内皮素-1的含量:氯沙坦组和依拉普利组在一定剂量范围内(氯沙坦组0.1～100μmol/L,依拉普利组1.0～100μmol/L)内皮素水平显著降低(P<0.05或P<0.01),两组之间比较,氯沙坦组显著低于依拉普利组(P<0.05)。结论:血管紧张素ⅡAT1受体抑制氯沙坦与血管紧张素转换酶抑制剂依拉普利均能有效抑制体外培养的血管平滑肌细胞增殖,两者作用差异无显者性,氯沙坦和依拉普利均能有效降低血管平滑肌细胞分泌内皮素水平,前者作用更显著。     

同型半胱氨酸对大鼠血管平滑肌细胞增殖及胶原生成的影响

目的:观察同型半胱氨酸的浓度对Ⅰ,Ⅲ,Ⅳ和Ⅵ型胶原的产生以及大鼠血管平滑肌细胞增殖效应的影响。方法:实验于2005-02/2006-04在瑞金医院心内科实验室完成。①采用组织块贴壁法原代培养大鼠胸主动脉平滑肌细胞,用不同浓度的同型半胱氨酸(0.025,0.05,0.1,0.2,0.5,1.0,1.5,2.0,3.0,5.0 mmol/L)刺激大鼠血管平滑肌细胞,并设对照孔(未加同型半胱氨酸)和空白孔(未加细胞)作对照。②分别作用12,24,48,72h,以四甲基偶氮唑盐法检测同型半胱氨酸对平滑肌细胞的活性细胞数量及细胞增殖情况;以5溴-2脱氧尿苷法检测同型半胱氨酸对大鼠血管平滑肌细胞DNA合成的作用;流式细胞仪观察细胞周期的变化;酶联免疫法测定胶原的含量。结果:①细胞增殖情况:在0.025,0.05 mmol/L的同型半胱氨酸浓度刺激下,12～48h血管平滑肌细胞增殖增加明显。②细胞DNA合成:与四甲基偶氮唑盐结果类似,24～48h时,在浓度为0.025,0.05 mmol/L的同型半胱氨酸刺激下细胞合成DNA增加(24h:432±33,774±52;48h:582±32,816±62),其促增殖作用增强(P<0.05);随着浓度的增加,大鼠血管平滑肌细胞合成DNA开始下降,至5 mmol/L浓度时最低。③细胞周期的变化:24h时在浓度为0.025,0.05 mmol/L的同型半胱氨酸刺激下增殖的细胞S期的百分含量较对照组和同型半胱氨酸其他浓度组明显增加。④胶原的含量:细胞的Ⅰ型和Ⅳ型胶原分泌随着同型半胱氨酸浓度的升高呈现剂量依赖性的增高模式。Ⅲ型胶原有轻度的升高,无统计学上意义。高浓度的同型半胱氨酸会减少Ⅵ型胶原的分泌,并呈剂量依赖性(r2=0.41;P<0.001)。结论:较低浓度的同型半胱氨酸刺激大鼠血管平滑肌细胞的增殖加速;并可能通过改变纤维斑块中的胶原构成类型导致了斑块的不稳定性和易损性,最终加速了粥样斑块的发生和发展。     

超声联合微泡对不同细胞周期血管平滑肌细胞增殖和凋亡的影响

目的 探讨超声联合微泡对不同细胞周期血管平滑肌细胞(VSMCs)增殖和凋亡的影响.方法 组织贴块法培养大鼠胸主动脉VSMCs,采用血清饥饿法和胸苷双阻断法使细胞同步化, 并用流式细胞仪分析同步化结果.以频率1 MHz、声强0.3 W/cm2的连续波超声联合脂质微泡辐照不同细胞周期的VSMCs 120 s,分别用噻唑蓝(MTT)比色法、流式细胞仪AnnexinV/PI染色、免疫细胞化学技术检测VSMCs的增殖、凋亡和增殖细胞核抗原(PCNA)表达.结果 成功获得同步化的G0/G1期和S期VSMCs,其同步化率分别为89.53%和66.87%.超声联合微泡可显著抑制S期细胞的增殖并下调PCNA蛋白表达,对G0/G1期细胞的增殖和PCNA表达无明显影响;G0/G1期和S期细胞的凋亡率均较辐照前增高,且对于S期细胞超声联合微泡诱导凋亡的作用更为显著.结论 超声联合微泡对处于增殖状态的VSMCs具有显著的抑制增殖和诱导凋亡的作用.     

蜂胶水提液影响血管紧张素Ⅱ促血管平滑肌细胞增殖的作用

目的：观察蜂胶水提液对血管紧张素Ⅱ诱导的人脐动脉平滑肌细胞增殖作用的影响。方法：实验于2005-03／2006-04在泰山医学院基础医学研究所完成。组织块法培养人脐动脉平滑肌细胞。取3～5代细胞进行实验。将培养的人脐动脉平滑肌细胞随机分为4组：①对照组：不加任何药物。②模型组：加入100nmol／L的血管紧张素Ⅱ。③蜂胶组：分别加入50mg／L、100mg／L、200mg,／L的蜂胶水提液预处理2h后，再加入终浓度为100nmol／L的血管紧张素Ⅱ。④氯沙坦组：加入1．5μmol／L的氯沙坦预处理2h后，再加入终浓度为100nmol／L的血管紧张素Ⅱ。同步化后，按分组分别加入处理药物孵育24h，倒置显微镜下动态观察细胞形态学的变化，同时计数细胞存活率，并用血细胞计数板计数各组细胞。采用流式细胞仪检测细胞周期，并分析细胞不同周期所占比例。采用免疫细胞化学检测增殖细胞核抗原。计算增殖细胞核抗原阳性细胞百分率。增殖细胞核抗原阳性细胞百分率（％）=增殖细胞核抗原阳性细胞总数／血管平滑肌细胞总数&;#215;100％。结果：①相差倒置显微镜下观察各组细胞加药前后形态学无明显变化，细胞存活率均达95．0％以上。②模型组细胞计数高于对照组和氯沙坦组（P〈0．01），100mg／L和200mg／L蜂胶组低于模型组（P〈0．01）；50mg／L和100mg／L蜂胶组高于氯沙坦组（P〈0．01），200mg／L蜂胶组与氯沙坦组差异无显著性（P〉0．05）。③模型组G0／G1期细胞百分比低于对照组、氯沙坦组（P〈0．01）；100mg／L和200mg／L蜂胶组高于模型组（P〈0.01）150mg／L蜂胶组低于氯沙坦组（P〈0.05），100mg／L、200mg／L蜂胶组与氯沙坦组差异显著性（P〉0．05）。④模型组增殖细胞核抗原阳性率高于对照组、氯沙坦组（P〈0．01）；100mg／L和200mg／L蜂胶组低于模型组（P〈0．01），蜂胶各浓度组与氯沙坦组间差异无显著性意义。结论：血管紧张素Ⅱ诱导血管平滑肌细胞的增殖，氯沙坦能阻滞该作用；一定浓度的蜂胶水提液可抑制血管紧张素Ⅱ诱导的血管平滑肌细胞的增殖，其机制可能与限制细胞由G1期向S期转变及增殖细胞核抗原的表达有关。     

氯沙坦对自发性高血压大鼠血管内皮功能和超微结构的影响

目的 :探讨氯沙坦 (lostartan)对自发性高血压大鼠 (SHR)血压、血管内皮细胞功能、内皮细胞超微结构及淋巴细胞钙 [Ca2 ] i的影响。方法 :SHR共 2 8只 ,分成 3组 ,分别为 3月龄对照组 (SHR1) ,6月龄对照组 (SHR2 )和losartan治疗组 (SHR3 )。治疗组从 3月龄开始予losartan 2 0mg·kg-1·d-1治疗至 6月龄。治疗前后检测鼠尾收缩压、淋巴细胞胞浆游离钙 [Ca2 ] i、ET 1、NO ,并观察大鼠肠系膜动脉内皮细胞超微结构。结果 :losartan对SHR有显著降压作用。治疗前SHR的淋巴细胞钙 [Ca2 ] i、ET 1水平均显著性增加 ,NO水平显著下降 ,随鼠龄增大而加大。肠系膜动脉内皮细胞出现明显肿胀、变形 ,比表面均显著减少。经losartan治疗后 ,在降压的同时 ,淋巴细胞[Ca2 ] i、ET 1显著下降 ,NO显著上升 ,血管内皮细胞超微结构的损害得到明显逆转。结论 :细胞内钙在losartan改善高血压血管内皮功能失调作用中可能起着重要的信使作用     

过氧化氢酶过度表达对血管平滑肌细胞增殖的影响

目的:探讨腺病毒载体介导的过氧化氢酶基因转染对体外培养的人血管平滑肌细胞增殖的影响。方法:用含过氧化氢酶基因的重组腺病毒(AdCat)转染人血管平滑肌细胞,应用四甲基偶氮唑蓝(MTT)方法观察血管平滑肌细胞的增殖活性,同时用流式细胞术观察血管平滑肌细胞细胞周期的变化。结果:MTT比色法分析显示AdCat组明显抑制细胞增殖,与对照组相比差异有显著性(P<0.05);细胞周期分析发现AdCat组G0/G1期分布百分率显著高于对照组,而S、G2/M期分布百分率显著低于对照组,细胞增殖能力下降(P<0.05)。结论:腺病毒载体介导的过氧化氢酶基因转染能抑制人血管平滑肌细胞的增殖。     

超声联合微泡对不同细胞周期血管平滑肌细胞增殖和凋亡的影响

Objective To investigate the effect of microbubbles mediated ultrasound insonation on proliferation and apoptosis of vascular smooth muscle cells (VSMCs) in different phase of cell cycle. Methods Rat thoracic aortic VSMCs were cultured in vitro by the method of tissue adherence. The cells were synchronized by the methods of serum starvation and double thymidine block. The synchronization results were detected by flow eytometer. VSMCs in different phases of cell cycle were exposed to 1 MHz continuous waves ultrasound for 120 s at intensity 0.3 W/cm2 in the presence of lipid-coated microbubbles (1 ml/L). Apoptosis of VSMCs was analyzed by AnnexinV/PI staining using flow eytometry. The proliferation and the proliferating cell nuclear antigen(PCNA) protein expression of VSMCs were detected by MTT assay and immunoeytochemistry, respectively. Results The synchronized G0/G1 and S phase VSMCs were achieved, with synchronized rates to 89.53 % and 66.87 %, respectively. Ultrasound sonication for 120 s with microbubbles could significantly inhibit the proliferation and downregulate the PCNA expression of S phase VSMCs,but the proliferation and PCNA expression of G0/G1 phase VSMCs were not affected. After treatment of ultrasound with microbubbles, the apoptotic ratio were found to reach (7.05 ± 2.04)% in G0/G1 phase VSMCs and (27.01 ±3.87)% in S phase VSMCs. Conclusions Microbubbles mediated ultrasound insonation can significantly inhabit the proliferation and induce apoptosis in VSMCs at proliferation stage.     

超声联合微泡对不同细胞周期血管平滑肌细胞增殖和凋亡的影响

Objective To investigate the effect of microbubbles mediated ultrasound insonation on proliferation and apoptosis of vascular smooth muscle cells (VSMCs) in different phase of cell cycle. Methods Rat thoracic aortic VSMCs were cultured in vitro by the method of tissue adherence. The cells were synchronized by the methods of serum starvation and double thymidine block. The synchronization results were detected by flow eytometer. VSMCs in different phases of cell cycle were exposed to 1 MHz continuous waves ultrasound for 120 s at intensity 0.3 W/cm2 in the presence of lipid-coated microbubbles (1 ml/L). Apoptosis of VSMCs was analyzed by AnnexinV/PI staining using flow eytometry. The proliferation and the proliferating cell nuclear antigen(PCNA) protein expression of VSMCs were detected by MTT assay and immunoeytochemistry, respectively. Results The synchronized G0/G1 and S phase VSMCs were achieved, with synchronized rates to 89.53 % and 66.87 %, respectively. Ultrasound sonication for 120 s with microbubbles could significantly inhibit the proliferation and downregulate the PCNA expression of S phase VSMCs,but the proliferation and PCNA expression of G0/G1 phase VSMCs were not affected. After treatment of ultrasound with microbubbles, the apoptotic ratio were found to reach (7.05 ± 2.04)% in G0/G1 phase VSMCs and (27.01 ±3.87)% in S phase VSMCs. Conclusions Microbubbles mediated ultrasound insonation can significantly inhabit the proliferation and induce apoptosis in VSMCs at proliferation stage.     

超声联合微泡对不同细胞周期血管平滑肌细胞增殖和凋亡的影响

Objective To investigate the effect of microbubbles mediated ultrasound insonation on proliferation and apoptosis of vascular smooth muscle cells (VSMCs) in different phase of cell cycle. Methods Rat thoracic aortic VSMCs were cultured in vitro by the method of tissue adherence. The cells were synchronized by the methods of serum starvation and double thymidine block. The synchronization results were detected by flow eytometer. VSMCs in different phases of cell cycle were exposed to 1 MHz continuous waves ultrasound for 120 s at intensity 0.3 W/cm2 in the presence of lipid-coated microbubbles (1 ml/L). Apoptosis of VSMCs was analyzed by AnnexinV/PI staining using flow eytometry. The proliferation and the proliferating cell nuclear antigen(PCNA) protein expression of VSMCs were detected by MTT assay and immunoeytochemistry, respectively. Results The synchronized G0/G1 and S phase VSMCs were achieved, with synchronized rates to 89.53 % and 66.87 %, respectively. Ultrasound sonication for 120 s with microbubbles could significantly inhibit the proliferation and downregulate the PCNA expression of S phase VSMCs,but the proliferation and PCNA expression of G0/G1 phase VSMCs were not affected. After treatment of ultrasound with microbubbles, the apoptotic ratio were found to reach (7.05 ± 2.04)% in G0/G1 phase VSMCs and (27.01 ±3.87)% in S phase VSMCs. Conclusions Microbubbles mediated ultrasound insonation can significantly inhabit the proliferation and induce apoptosis in VSMCs at proliferation stage.     

超声联合微泡对不同细胞周期血管平滑肌细胞增殖和凋亡的影响

Objective To investigate the effect of microbubbles mediated ultrasound insonation on proliferation and apoptosis of vascular smooth muscle cells (VSMCs) in different phase of cell cycle. Methods Rat thoracic aortic VSMCs were cultured in vitro by the method of tissue adherence. The cells were synchronized by the methods of serum starvation and double thymidine block. The synchronization results were detected by flow eytometer. VSMCs in different phases of cell cycle were exposed to 1 MHz continuous waves ultrasound for 120 s at intensity 0.3 W/cm2 in the presence of lipid-coated microbubbles (1 ml/L). Apoptosis of VSMCs was analyzed by AnnexinV/PI staining using flow eytometry. The proliferation and the proliferating cell nuclear antigen(PCNA) protein expression of VSMCs were detected by MTT assay and immunoeytochemistry, respectively. Results The synchronized G0/G1 and S phase VSMCs were achieved, with synchronized rates to 89.53 % and 66.87 %, respectively. Ultrasound sonication for 120 s with microbubbles could significantly inhibit the proliferation and downregulate the PCNA expression of S phase VSMCs,but the proliferation and PCNA expression of G0/G1 phase VSMCs were not affected. After treatment of ultrasound with microbubbles, the apoptotic ratio were found to reach (7.05 ± 2.04)% in G0/G1 phase VSMCs and (27.01 ±3.87)% in S phase VSMCs. Conclusions Microbubbles mediated ultrasound insonation can significantly inhabit the proliferation and induce apoptosis in VSMCs at proliferation stage.     

Effects of 2-deoxy-D-glucose on proliferation of vascular smooth muscle cells and endothelial cells

2-Deoxy-D-glucose (2-DG) is a glucose analogue that has been proposed for cancer therapy due to its cytostatic properties. Its effect on the proliferation of smooth muscle cells and endothelial cells has not been fully clarified. The aims of this study were to investigate the effects of 2-DG on the proliferation of porcine aortic endothelial cells (PAEC) and porcine smooth muscle cells (PSMC), to establish an overview of its dose-dependent inhibitory capacity and to examine whether the short-term incubation of cells with 2-DG has an impact on cell proliferation in culture. Our results showed a dose-dependent significant inhibitory effect on proliferation, which was more pronounced in PSMC than in PAEC. Even after short-term incubation of cells with 2-DG, relevant inhibition of proliferation was documented. The clinical application of 2-DG might be a promising concept by inhibiting cells that show a potentially rapid proliferation in response to non-malignant stimuli, such as smooth muscle cells after intracoronary stenting.     

Specific binding of endothelin on human vascular smooth muscle cells in culture.

Endothelin is a newly discovered, potent vasoconstrictor peptide secreted by endothelial cells. The binding of endothelin was studied on cultured human vascular smooth muscle cells obtained from umbilical veins. A single specific binding site for 125I-endothelin was identified, with an apparent Kd of 126 pM and a maximal binding capacity of approximately 10,000 sites per smooth muscle cell. At room temperature the binding was saturable, reached equilibrium at 2 h (using 20 pM endothelin), and was slowly and only partially reversed by unlabeled endothelin. The calcium antagonists nifedipine, nicardipine, and diltiazem did not compete for the same binding site. Conditioned medium from cultured human umbilical vein endothelial cells inhibited the binding of 125I-endothelin dose dependently. This effect was antagonized by anti-endothelin antiserum. We conclude that human umbilical vein smooth muscle cells possess specific binding sites for endothelin, and that human endothelial cells secrete an endothelinlike material.     

gax基因与血管平滑肌细胞增殖

gax基因是一个主要存在于心血管系统的同源盒基因,能显著抑制血管平滑肌细胞增殖,有望成为防治动脉粥样硬化和经皮血管介入治疗后再狭窄的靶基因。     

雷公藤内酯醇抑制血管平滑肌细胞增殖的研究

目的:探讨雷公藤内酯醇对血清诱导的大鼠血管平滑肌细胞(VSMC)增生的影响及其作用机制。方法:体外培养大鼠胸主动脉平滑肌细胞,用细胞计数法观察雷公藤内酯醇对细胞增生的抑制作用,采用流式细胞仪进行细胞周期分析,逆转录-聚合酶链反应(RT-PCR)法检测细胞c-fos的mRNA表达水平。结果:雷公藤内酯醇明显抑制血清诱导的大鼠VSMC增生;阻断细胞周期中细胞由G0/G1期向S期转化;RT-PCR检测显示雷公藤内酯醇能明显抑制原癌基因c-fos的表达,其作用呈剂量依赖性。结论:雷公藤内酯醇可抑制血清诱导的大鼠VSMC增生,下调原癌基因c-fos的表达。     

tMfn2基因抑制血管平滑肌细胞增殖的作用与机制

目的 比较线粒体融合素基因2(Mfn2)和去除穿膜区序列的大鼠线粒体融合素基因2(tMfn2)对大鼠血管平滑肌细胞(VSMCs)增殖的作用,探讨tMfn2基因对VSMCs增殖的影响及其相关的信号通路.方法 用携带tMfn2基因和Mfn2基因的重组腺病毒(Adv-tMfn2和Adv-Mfn2)感染VSMCs,检测tMfn2蛋白和Mfn2蛋白在细胞中的表达水平;细胞计数法、四甲基偶氮唑盐(MTT)法检测VSMCs的增殖;流式细胞术检测tMfn2基因对VSMCs周期的影响;Western blot分析各组磷酸化ERK1/2和磷酸化Raf-1蛋白表达水平的变化;采用方差分析对数据进行统计学处理.结果 Adv-tMfn2和Adv-Mfn2感染VSMCs后能有效表达出相应蛋白;细胞计数和MTT结果显示,tMfn2和Mfn2均使VSMCs增殖受到明显抑制(P<0.01),且前者较后者抑制效果更明显(P<0.01);流式细胞术结果表明tMfn2和Mfn2使多数VSMCs停滞于G0/G1期,细胞比例为(88.01±4.38)%和(67.43±6.21)%,可见tMfn2基因对细胞剧期的影响更明显(P<0.01).进一步研究表明tMfn2比Mfn2更能降低磷酸化ERK1/2(p-ERK1/2)和磷酸化Raf-1(p-Raf-1)的表达水平(P<0.01).结论 与Mfn2基因相比,tMfn2基因更能显著抑制VSMCs增殖,使细胞周期停滞于G0/G1期.这一作用主要通过抑制Ras-Raf-ERK1/2信号通路,下调磷酸化Raf-1蛋白表达,进而抑制ERK1/2的磷酸化而实现.     

动脉粥样硬化模型兔血管平滑肌细胞增殖与癫狂梦醒汤的干预

背景:现代临床研究表明癫狂梦醒汤能够治疗神经官能症、更年期综合征、癔病、老年痴呆等精神系统疾病。目的:观察癫狂梦醒汤对动脉粥样硬化模型兔血管平滑肌细胞增殖的影响。方法:将32只日本大耳白兔随机分成空白对照组、模型组、癫狂梦醒汤组、辛伐他汀组,分别给予普通饲料、高脂饲料、高脂饲料+癫狂梦醒汤、高脂饲料+辛伐他汀进行干预,喂养至第12周末。结果与结论:喂养高脂饲料成功建立动脉粥样硬化模型,模型组有严重的动脉粥样硬化病理改变,增殖细胞核抗原、血小板源生长因子B蛋白表达明显升高,平滑肌细胞呈合成型改变;癫狂梦醒汤组及辛伐他汀组动脉粥样硬化病变明显减轻,增殖细胞核抗原、血小板源生长因子B蛋白表达明显下降(P<0.01),平滑肌细胞接近"收缩型"改变。结果可见癫狂梦醒汤可抑制血管平滑肌细胞增殖,延缓动脉粥样硬化发生发展,这一作用可能是通过抑制增殖细胞核抗原、血小板源生长因子B蛋白表达来实现的。     

表没食子儿茶素没食子酸酯对同型半胱氨酸促血管平滑肌细胞增殖的保护作用

目的观察表没食子儿茶素没食子酸酯(EGCG)在同型半胱氨酸(Hcy)促血管平滑肌细胞(VSMCs)增殖中的保护作用。方法采用不同的实验试剂培养人主动脉平滑肌细胞(HASMCs),分为对照组(control)、Hcy组(Hcy 100、200、500、1 000μmol/L)、EGCG组(EGCG 5、10、20μmol/L)、Hcy+EGCG组(Hcy 500μmol/L+EGCG 5μmol/L、Hcy 500μmol/L+EGCG 10μmol/L、Hcy 500μmol/L+EGCG 20μmol/L),在培养的24 h,采用CCK-8法、5-溴脱氧尿嘧啶核苷(Brd U)标记法观察细胞增殖情况;酶联免疫吸附试验(ELISA)测定血管紧张素Ⅱ(Ang II)浓度,Western印迹法测定Ang II受体1(AT-1R)蛋白表达水平。结果干预24 h后,与对照组相比,Hcy各组细胞增殖均显著增加(P0.05),EGCG 10、20μmol/L组细胞增殖显著减少(P0.05);与Hcy 500μmol/L组相比,加入EGCG 10、20μmol/L干预后细胞增殖显著减少(P0.01),Ang II浓度及AT-1R蛋白表达水平显著降低(P0.01)。结论 EGCG可抑制Hcy诱导的VSMCs增殖。