Arterial Wall Adaptation under Elevated Longitudinal Stretch in Organ Culture

Arteries in vivo are subjected to large longitudinal stretch which may change significantly due to vascular disease and surgery. However, little is known about the effect of longitudinal stretch on vascular function and wall remodeling, although the effects of tensile and shear stress from blood pressure and flow have been well documented. To study the effect of longitudinal stretch on vascular function and wall remodeling, porcine carotid arteries were longitudinally stretched 20% more than in vivo for 5 days while being maintained in an ex vivo organ culture system under conditions of pulsatile flow at physiologic pressure. Vessel viability was demonstrated by strong vasomotor responses to norepinephrine (NE, 10^-6M), carbachol (10^-6M), and sodium nitroprusside (10^-5M), as well as by dense staining for mitochondrial activity and a low occurrence of cell necrosis. Cell proliferation was examined by incorporation of bromodeoxyuridine (BrdU). Results showed that arteries maintain normal structure and viability after 5 days in organ culture. Both the stretched and control arteries demonstrated significant contractile responses. For example, both stretched and control arteries showed approximately 10% diameter contraction in response to NE. Stretched arteries contained 8% BrdU-positive cells compared to 5% in controls (p < 0.05). These results indicate that longitudinal stretch promotes cell proliferation in arteries while maintaining arterial function. © 2003 Biomedical Engineering Society. PAC2003: 8719Rr, 8717Ee, 8719Uv     

FOXO1参与高血压条件下异常张应变诱导的血管平滑肌细胞增殖

目的 探讨高血压条件下异常升高的周期性张应变刺激对血管平滑肌细胞（vascular smooth muscle cells, VSMCs）增殖的影响,以及Forkhead转录因子1（FOXO1）在其中可能的作用。方法 构建腹主动脉缩窄高血压大鼠模型,并以假手术组为对照,应用FX-4000T体外周期性张应变加载系统,分别对VSMCs施加5%的生理性张应变和15%的高血压病理性张应变。Western blot检测VSMCs的FOXO1及p-FOXO1表达水平,BrdU法检测VSMCs 增殖活性。RNA干扰技术抑制VSMCs的FOXO1表达,检测FOXO1、p-FOXO1表达以及VSMCs增殖活性变化。结果 腹主动脉缩窄术后 2和4周,大鼠血压较假手术大鼠明显增高。与假手术大鼠相比,高血压大鼠血管壁细胞增殖活性明显增高,同时 FOXO1及 p-FOXO1表达水平也显著性升高。细胞实验表明,与5%张应变组相比,15%张应变加载显著上调VSMCs的FOXO1、p-FOXO1表达水平,以及VSMCs增殖活性。静态条件下RNA干扰抑制VSMCs的FOXO1及p-FOXO1表达,VSMCs的增殖活性明显降低。结论 高血压病理条件下,异常增高的周期性张应变可能通过促进 FOXO1表达和磷酸化诱导VSMCs增殖。以动物模型观察现象,在细胞分子水平探讨机制,旨在明确FOXO1在高血压血管重建中的作用及其力学生物学机制,为阐明高血压血管重建的发病机理和药物治疗靶标的研究提供新的实验依据。     

Cyclic stretch affects pulmonary endothelial cell control of pulmonary smooth muscle cell growth

Endothelial cells are subjected to mechanical forces in the form of cyclic stretch resulting from blood pulsatility. Pulmonary artery endothelial cells (PAECs) produce factors that stimulate and inhibit pulmonary artery smooth muscle cell (PASMC) growth. We hypothesized that PAECs exposed to cyclic stretch secrete proteins that inhibit PASMC growth. Media from PAECs exposed to cyclic stretch significantly inhibited PASMC growth in a time-dependent manner. Lyophilized material isolated from stretched PAEC-conditioned media significantly inhibited PASMC growth in a dose-dependent manner. This inhibition was reversed by trypsin inactivation, which is consistent with the relevant factor being a protein(s). To identify proteins that inhibited cell growth in conditioned media from stretched PAECs, we used proteomic techniques and found that thrombospondin (TSP)-1, a natural antiangiogenic factor, was up-regulated by stretch. In vitro, exogenous TSP-1 inhibited PASMC growth. TSP-1-blocking antibodies reversed conditioned media-induced inhibition of PASMC growth. Cyclic stretched PAECs secrete protein(s) that inhibit PASMC proliferation. TSP-1 may be, at least in part, responsible for this inhibition. The complete identification and understanding of the secreted proteome of stretched PAECs may lead to new insights into the pathophysiology of pulmonary vascular remodeling.     

microRNA-214-3p在周期性张应变诱导内皮祖细胞分化和增殖中的作用

目的探讨microRNA-214-3p(miR-214-3p)在周期性张应变诱导内皮祖细胞(endothelial progenitor cells, EPCs)分化和增殖中的作用。方法采用FX-5000T细胞周期性张应变加载装置对EPCs施加生理水平的周期性张应变(5%幅度、1.25 Hz频率),加载时间24 h。应用miRNAs芯片筛选周期性张应变调控下差异表达的miRNAs,并挑选miR-214-3p进行深入研究。实时荧光定量PCR方法检测EPCs内平滑肌细胞(vascular smooth muscle cells, VSMCs)相标志分子的表达,BrdU结合酶联免疫吸附ELISA法检测EPCs增殖功能。之后,使用miR-214-3p抑制剂抑制miR-214-3p的表达,检测EPC内VSMC相标志分子表达及EPCs增殖。结果周期性张应变显著抑制miR-214-3p表达,并抑制EPCs向VSMC相分化,同时显著促进EPCs增殖。在静态条件下,使用miR-214-3p抑制剂干扰miR-214-3p的表达,miR-214-3p水平下降同样会抑制EPCs向VSMC相分化,并且诱导EPCs增殖能力显著上升。结论生理水平的周期性张应变能够抑制EPCs内miR-214-3p表达,从而抑制EPCs向VSMC相分化,并且促进EPCs增殖。研究结果为血管损伤的治疗提供新的治疗靶点。     

Gastrodin inhibits cell proliferation in vascular smooth muscle cells and attenuates neointima formation in vivo

Vascular smooth muscle cell (VSMC) proliferation plays a critical role in the development of vascular diseases. In the present study, we tested the efficacy and the mechanisms of action of gastrodin, a bioactive component of the Chinese herb Gastrodia elata Bl, in relation to platelet-derived growth factor-BB (PDGF-BB)-dependent cell proliferation and neointima formation after acute vascular injury. Cell experiments were performed with VSMCs isolated from rat aortas. WST and BrdU incorporation assays were used to evaluate VSMC proliferation. Eight-week-old C57BL/6?mice were used for the animal experiments. Gastrodin (150?mg/kg/day) was administered in the animal chow for 14?days, and the mice were subjected to wire injury of the left carotid artery. Our data demonstrated that gastrodin attenuated the VSMC proliferation induced by PDGF-BB, as assessed by WST assay and BrdU incorporation. Gastrodin influenced the S-phase entry of VSMCs and stabilised p27Kip1 expression. In addition, pre-incubation with sinomenine prior to PDGF-BB stimulation led to increased smooth muscle-specific gene expression, thereby inhibiting VSMC dedifferentiation. Gastrodin treatment also reduced the intimal area and the number of PCNA-positive cells. Furthermore, PDGF-BB-induced phosphorylation of ERK1/2, p38 MAPK, Akt and GSK3β was suppressed by gastrodin. Our results suggest that gastrodin can inhibit VSMC proliferation and attenuate neointimal hyperplasia in response to vascular injury. Furthermore, the ERK1/2, p38 MAPK and Akt/GSK3β signalling pathways were found to be involved in the effects of gastrodin.     

Correlative association between circadian expression of mousePer2 gene and the proliferation of the neural stem cells

We examined the circadian expression of mousePeriod (mPer) genes (mPer1 and mPer2) and the proliferation of the neural stem cells in vitro. The neural stem cells from the ganglionic eminence of embryonic mice were expanded by the neurosphere method and then treated with epidermal growth factor (EGF) to stimulate their mitotic activity. The time courses of the proliferation were examined by WST-8 assay and bromodeoxyuridine (BrdU) incorporation assay and the expression of mPer1 and mPer2 genes was examined by RT-PCR and immunocytochemistry. We have found that EGF treatment elicited the circadian change in both the increase in viable cell number and DNA synthesis activity of the neural stem cells. Also, the gene expression of mPer2, but not mPer1, changed rhythmically with a period of 24 h and correlated negatively with the DNA synthesis activity rhythm. Furthermore, the treatment with an antisense oligonucleotide against mPer2 increased the DNA synthesis activity of the neural stem cells. These results suggest that mPer2 might periodically suppress the proliferation of neural stem cells.     

Mechanical stretching of human saphenous vein grafts induces expression and activation of matrix-degrading enzymes associated with vascular tissue injury and repair.

After coronary artery bypass surgery, saphenous vein graft occlusion occurs through tissue remodeling. Although a likely trigger, the role of preparative mechanical injury incurred by the graft is not yet understood. We studied the early effects of simple mechanical injury on human saphenous vein grafts by exposing them to longitudinal stretch, a deformation which potentially occurs during surgery. We then maintained ex vivo for up to 7 days matched pairs of experimentally stretched and nonstretched (control) vein segments and examined the expression and activation of matrix metalloproteinases (MMPs) and integrin alphav, molecules implicated in vascular remodeling. At peak expression on day 3, stretched vein secreted 177 +/- 16% active MMP-2 (P < 0.01), 161 +/- 36% (P < 0.05) pro-MMP-9, and contained 206 +/- 18% (P < 0.01) alphav, a receptor for active MMP-2, compared to control. In situ gelatinase activity was present in the intima and adventitia of stretched veins, but not of control, and correlated spatially with expression of alphav. Stretch also increased severalfold cell proliferation (1.27 +/- 0.4 vs. 0.23 +/- 0.05% in control, P < 0.05), as assessed by bromodeoxyuridine incorporation. Furthermore, we found that cell proliferation colocalized with gelatinase activity and alphav in the adventitia. Our results show that a single longitudinal stretch of vein grafts produces significant changes in the expression and activation of key molecules in vascular remodeling. We also found support for the notion that the adventitial layer contributes to vein graft remodeling.     

钙敏感受体通过PI3K信号通路介导缺氧诱导的大鼠肺动脉平滑肌细胞增殖

目的:探讨钙敏感受体(CaSR)在缺氧诱导的大鼠肺动脉平滑肌细胞(PASMCs)增殖中的信号转导途径。方法:Ⅱ型胶原酶消化法提取、培养大鼠PASMCs。通过缺氧培养箱内(93%N₂、2%O₂、5%CO₂)培养24h的方法复制细胞缺氧模型。应用Western blotting分析不同处理情况下细胞周期素D1(cyclin D1)及磷酸化的蛋白激酶B(p-Akt)在PASMCs中的表达;采用流式细胞术检测不同处理因素对细胞增殖周期及增殖指数的影响,应用BrdU掺入法分析不同处理因素对细胞DNA合成的影响。结果:缺氧引起PASMCs的cyclin D1及p-Akt表达水平上调,增加BrdU掺入量、S期细胞数量和细胞增殖指数,GdCl₃能够放大缺氧的作用,但上述效应可以被LY294002抑制。结论:CaSR通过PI3K/Akt信号通路参与缺氧诱导的大鼠PASMCs增殖。     

尼古丁对大鼠血管平滑肌细胞增殖和凋亡的影响

目的 探讨尼古丁对大鼠胸主动脉血管平滑肌细胞(VSMCs)增殖和凋亡的影响.方法用终浓度为100 μmol/L的尼古丁作用于体外培养的大鼠VSMCs 24h,不加尼古丁的细胞作为对照组,应用荧光显微镜和扫描电子显微镜观察各组细胞凋亡的形态,BrdU-ELISA和流式细胞术检测各组细胞增殖和凋亡率,进而确定尼古丁对VSM...     

趋化素通过上调磷酸化JNK促进小鼠血管平滑肌细胞的增殖

 目的: 利用慢病毒构建趋化素基因缺陷性小鼠血管平滑肌细胞株,观察沉默趋化素基因后血管平滑肌细胞的增殖情况并探讨其机制。方法: 将正常血管平滑肌细胞、趋化素基因干扰对照血管平滑肌细胞株和趋化素基因缺陷性血管平滑肌细胞株分成正常组、增殖组、对照组和沉默组,增殖组加入血小板源性生长因子BB促进增殖,采用细胞计数和BrdU法检测血管平滑肌细胞增殖,采用Western blot检测丝裂原激活蛋白激酶( MAPK)信号通路的蛋白水平。结果: 增殖组血管平滑肌细胞的细胞数目和BrdU的A值显著高于正常组(P<0.05);与正常组相比,沉默组的血管平滑肌细胞数目和BrdU的A值显著降低(P<0.05);与此同时,对照组与正常组之间的血管平滑肌细胞增殖情况无明显差异。各组血管平滑肌细胞之间的p-ERK1/2、ERK1/2、p-p38 MAPK和p38 MAPK水平无明显变化,增殖组血管平滑肌细胞的p-JNK蛋白表达增加,而沉默组血管平滑肌细胞的p-JNK水平下降。结论: 趋化素具有促进小鼠血管平滑肌细胞增殖的作用,该作用可能与p-JNK表达上调相关。     

Nitric oxide regulates stretch-induced proliferation in C2C12 myoblasts

Mechanical stretch of skeletal muscle activates nitric oxide (NO) production and is an important stimulator of satellite cell proliferation. Further, cyclooxygenase (COX) activity has been shown to promote satellite cell proliferation in response to stretch. Since COX-2 expression in skeletal muscle can be regulated by NO we sought to determine if NO is required for stretch-induced myoblast proliferation and whether supplemental NO can counter the effects of COX-2 and NF-κB inhibitors. C2C12 myoblasts were cultured for 24 h, then switched to medium containing either the NOS inhibitor, l-NAME (200 μM), the COX-2 specific inhibitor NS-398 (100 μM), the NF-κB inhibiting antioxidant, PDTC (5 mM), the nitric oxide donor, DETA-NONOate (10–100 μM) or no supplement (control) for 24 h. Subgroups of each treatment were exposed to 1 h of 15% cyclic stretch (1 Hz), and were then allowed to proliferate for 24 h before fixing. Proliferation was measured by BrdU incorporation during the last hour before fixing, and DAPI stain. Stretch induced a twofold increase in nuclear number compared to control, and this effect was completely inhibited by l-NAME, NS-398 or PDTC (P < 0.05). Although DETA-NONOate (10 μM) did not affect basal proliferation, the NO-donor augmented the stretch-induced increase in proliferation and rescued stretch-induced proliferation in NS-398-treated cells, but not in PDTC-treated cells. In conclusion, NO, COX-2, and NF-κB are necessary for stretch-induced proliferation of myoblasts. Although COX-2 and NF-κB are both involved in basal proliferation, NO does not affect basal growth. Thus, NO requires the synergistic effect of stretch in order to induce muscle cell proliferation.     

Mechanical stretch regulates TRPC expression and calcium entry in human myometrial smooth muscle cells

Stretch is known to stimulate myometrial hyperplasia and hypertrophy in early pregnancy and uterine contraction at term. We propose that transduction of the stretch signal involves alteration of intracellular calcium signalling, including changes in transient receptor potential canonical (TRPC) isoform expression. The aim of the present study was to investigate the effect of prolonged mechanical (tonic) stretch in vitro on human myometrial smooth muscle cell calcium signalling and TRPC expression. Cells were cultured from myometrial biopsies, obtained from women undergoing elective Caesarean section at term, grown on Flexiplates and subjected to 25% tonic mechanical stretch for 1, 4 and 14 h. Time-matched control cells were not stretched. Mechanical stretch (14 h) increased basal calcium entry and cyclopiazonic acid (CPA)-induced calcium/Mn(2+) entry (P < 0.05) in Fura-2 loaded cells. The calcium selectivity of CPA-thapsigarin induced inward currents, measured by patch clamp electrophysiology, was also increased in stretched cells compared with control cells (P < 0.05). Real time PCR and Western blot data demonstrated that TRPC3 and TRPC4 mRNA and TRPC3 protein expression were increased by stretch (P < 0.05), respectively. These data support the hypothesis that uterine stretch modulates uterine growth and contractility in pregnancy via alterations in calcium signalling.     

机械刺激对肝癌细胞形态及增殖周期的影响

本研究采用“四点弯曲梁加载装置” ,对培养的人肝癌细胞株SMMC 772 1施以拉伸刺激 ,通过显微计算机图像处理系统了解其形态变化 ,流式细胞仪了解其增殖行为 ,结果发现 (1)加载 2 4h后SMMC 772 1G2 -M期 8.6 3% ,对照组 15 .92 %。 (2 )加载 72h后SMMC 772 1铺展投影面积缩小。 (3)加载 2 4h后SMMC 772 1分裂指数 0 .4 6 ,对照组 0 .5 5。加载可部分抑制SMMC 772 1的生长。     

钙敏感受体通过PI3K/AKT通路对缺氧诱导的A549细胞增殖的影响

目的:探讨钙敏感受体(calcium-sensing receptor,CaSR)在缺氧诱导的A549及A549/DDP细胞增殖中的信号转导途径。方法:通过缺氧培养箱内(93%N_2、2%O_2、5%CO_2)培养24 h的方法复制细胞缺氧模型。应用Western blot技术分析PCNA及p-AKT蛋白不同处理情况下的表达水平;采用流式细胞技术检测不同处理因素对细胞周期及增殖指数的影响,应用BrdU掺入法分析不同处理因素对细胞DNA合成的影响。结果:缺氧引起A549及A549/DDP细胞PCNA及p-AKT蛋白水平上调,增加BrdU掺入量、S期细胞数量和细胞增殖指数,GdCl_3能够增强缺氧的作用,但上述效应可以被LY294002抑制。结论:PI3K/AKT信号通路在缺氧活化CaSR并促进A549及A549/DDP细胞增殖中起重要作用。     

Mechanical stimulation induces morphological and phenotypic changes in bone marrow-derived progenitor cells within a three-dimensional fibrin matrix

One of the major limitations in tissue engineering is cell sourcing. Multipotent progenitor cells appear to have many promising features for that purpose. Mechanical stimulation is known to play an important role in determining cell phenotype. The aim of this work was to investigate the effects of cyclic stretch on rat bone marrow derived progenitor cell (BMPC) morphology and smooth muscle-directed differentiation within a three-dimensional fibrin matrix. BMPCs were suspended in a fibrin gel, pipetted into the trough of Flexcell Tissue-Train plates, and stimulated with 10% longitudinal cyclic stretch at 1 Hz for 6 days. Unconstrained (stress- and strain-free) and static anchored (constrained but not stretched) samples were used as controls. Stress filament area per cell was increased in the stretched samples compared to static anchored and free-float controls. Cells in the free float controls were randomly aligned, while they aligned parallel to the direction of the stress or strain in the other groups. Immunofluorescence suggested an increased expression of smooth muscle markers (smooth muscle alpha actin and h1-calponin) in both stretched and constrained control samples, but not in unconstrained controls. Qualitative assessment suggested that collagen production was increased in both mechanically stimulated samples. Proliferation was inhibited in stretched samples compared to the constrained controls. This work suggests an ability of rat BMPCs to differentiate toward a smooth-muscle-cell-like lineage when exposed to biomechanical stimulation in a three-dimensional model. The observation that the constrained samples induced changes in BMPCs suggests that stress alone may be stimulatory, but addition of cyclic stretch appears to augment the responses.     

Myofibroblast and endothelial cell proliferation during murine myocardial infarct repair

Granulation tissue formation is a critical step in infarct repair, however, the kinetics of cell replication and the molecules that regulate this process are poorly understood. In uninjured mouse hearts and at 2 days post-infarction, very little DNA synthesis (measured by incorporation of a BrdU pulse) was detected in any cell type. Four days after permanent coronary occlusion, the rates of myofibroblast (smooth muscle alpha-actin and BrdU double-positive) and endothelial cell (CD31 and BrdU double-positive) proliferation were 15.4 +/- 1.1% and 2.9 +/- 0.5%, respectively. Most proliferating cells were located at the interface of the infarct and viable tissue. By 1 week, fibroblast and endothelial cell proliferation declined to 4.1 +/- 0.6% and 0.7 +/- 0.1%, respectively. In the 2-week infarct, the remaining necrosis had been phagocytosed, and fibroblast and endothelial cell proliferation were <0.5%. Although leukocytes were abundant throughout infarct repair, no significant proliferation was detected at any time in cells expressing CD45 or mac-3. Infarct size at 4 days was 38 +/- 5% of the left ventricle and contracted to 20 +/- 4% by 4 weeks. After 4 days, the chamber dilated to four times that of the control hearts and remained so for the duration of the time course. The vascular density (per mm(2)) declined from 3643 +/- 82 in control hearts to 2716 +/- 197 at 1 week and 1010 +/- 47 at 4 weeks post-myocardial infarction (MI). The average percent area occupied by vessels did not change significantly between the groups but the area/vessel ( micro m(2)) increased from 14.1 +/- 0.3 in control hearts to 16.9 +/- 1.9 at 1 week and 38.7 +/- 7.9 at 4 weeks post-MI. These data indicate that mitogens for fibroblasts and endothelial cells peak within 4 days of infarction in the mouse heart. This provides the basis for identifying the responsible molecules and developing strategies to alter wound repair and improve cardiac function.     

Protein kinase G activity prevents pathological-level nitric oxide-induced apoptosis and promotes DNA synthesis/cell proliferation in vascular smooth muscle cells

BackgroundProtein kinase G (PKG), a recognized downstream mediator of nitric oxide, is a key regulator of cardiovascular physiology and pathology. High-level stimulation of cyclic guanosine monophosphate/PKG signaling using high concentrations of nitric oxide donors, mimicking pathological conditions, induces apoptosis in vascular smooth muscle cells. In contrast, we have found that PKG at basal and moderately elevated activity prevents both spontaneous and toxin-induced apoptosis in many other cells. We hypothesized that PKG's apoptosis-regulatory role in vascular smooth muscle cells depends on PKG activation levels [low/basal-level activation prevents apoptosis, whereas high-level activation (hyperactivation) causes apoptosis]. Furthermore, we hypothesized that, although PKG hyperactivation inhibits vascular smooth muscle cell proliferation (potentially causing anti-atherogenic effects), basal PKG activity may promote vascular smooth muscle cell proliferation/atherogenesis.MethodsInvolvement of PKG in apoptosis and proliferation was determined in unpassaged vascular smooth muscle cells from mouse aorta. Western blot analysis was used to determine PKG expression, and activators/inhibitors of PKG activity were used to determine involvement in apoptosis (Hoechst staining and DNA-fragmentation ELISAs) and proliferation (cell count, MTT assay, and BrdU incorporation).ResultsBoth PKG-Iα and PKG-Iβ isoforms were expressed. Lower-level stimulation of PKG using the nitric oxide donor S-nitroso-acetylpenacillamine (10, 50 μM) significantly (P<.05) lowered spontaneous apoptosis, whereas S-nitroso-acetylpenacillamine at higher concentrations (500, 1000 μM) elevated apoptosis. Twenty-four-hour pretreatment with atrial natriuretic peptide, a PKG activator, completely prevented high-concentration, nitric oxide-induced apoptosis. Inhibition of basal PKG activity using highly selective PKG inhibitors, DT-2 and DT-3, significantly (P<.001) increased apoptosis and inhibited DNA synthesis/proliferation.ConclusionThe data suggest that basal/moderately elevated PKG activity protects against high/pathological-level nitric oxide-induced apoptosis and promotes DNA synthesis/proliferation in vascular smooth muscle cells, potentially important for atherogenesis.     

Lithium stimulates progenitor proliferation in cultured brain neurons

The number of neurons in the brain is controlled by production of new neurons and neuronal death. Neural progenitor proliferation in the developing and adult brain plays a prominent role in the production of new neurons. Here, we examined the effects of lithium, a mood-stabilizing drug, on neuronal proliferation in rat primary neuronal cultures. The incorporation of 5-bromo-2'-deoxyuridine (BrdU) into replicating DNA was used to label proliferating cells. BrdU incorporation was detected by immunocytochemistry in cerebellar granule cells prepared from postnatal rats and cerebral cortical cultures prepared from embryonic rats. Quantification of BrdU incorporation into cultures was performed by counting BrdU-positive cells and BrdU-coupled enzyme-linked immunosorbent assay. Both methods revealed that lithium increased BrdU incorporation in cerebellar granule cells and cerebral cortical cultures. Most BrdU-positive cells colocalized with nestin, a neuroblast cell marker, in cerebral cortical cultures. Blockade of DNA replication by cytosine arabinoside almost completely abolished BrdU incorporation, suggesting that lithium-induced BrdU incorporation was mainly due to enhanced DNA replication. Glutamate, glucocorticoids and haloperidol were found to markedly reduce neural progenitor proliferation in cerebellar granule cells. The presence of lithium prevented the loss of proliferation induced by these agents. Lithium-induced neural progenitor proliferation in vitro suggests that similar effects might occur in vivo and this action could also be related to its clinical efficacy. Cultured brain neurons may provide a valuable model for studying the molecular mechanisms underlying lithium-induced up-regulation of neural proliferation.     

血管组织工程生物支架材料细胞生物相容性实验研究

目的采用新方法研究天然生物支架材料胶原/透明质酸膜,明胶海绵的细胞相容性。方法应用WST-1法测定平滑肌细胞与材料的粘附率,增殖力,^3H-TDR掺入法测定DNA合成率,BrdU细胞标记免疫组化鉴定,分析组织工程生物支架材料的细胞相容性。结果WST-1法测定,^3H-TDR掺入法测定DNA合成率,BrdU细胞标记结果表明：胶原/透明质酸膜与平滑肌细胞的粘附率最高,细胞的增殖和代谢状况较好,明胶海绵较低。结论应用WST-1法测定,^3H-TDR掺入法测定DNA合成率,BrdU细胞标记方法研究细胞相容性方法简便可行;天然复合生物材料胶原/透明质酸膜具有较理想的细胞相容性。