Abstract:Aim To investigate the mitogenic effect of urotensin II on cells. Methods In cultured rat aorta smooth muscle cells (VSMC), tracheal smooth muscle cells (TSMC), cardiac fibroblasts (CF) and glomerular mesagial cells (GMC), UⅡ was used to stimulate these cells and levels of 3 H-TdR incorporation were used to evaluate the speed of DNA synthesis. Results UⅡ increased levels in concentration-dependent manner of 3 H-TdR incorporation of these cells significantly. But in different cells, UⅡ of same concentration did not induce same effect. 10 -10 mol/L UⅡ could increase levels of 3 H-TdR incorporation of CF and TSMC only, with the incorporation of CF higher than TSMC, while 10 -9 ～10 -8 mol/L UⅡ induced effect in the following order:CF>TSMC>GMC>VSMC. However, 10 -6 ～10 -7 mol/L UⅡ showed weaker stimulating effects on CF than lower concentration of UⅡ(10 -10 ～10 -8 mol/L). Conclusion These study provides evidence that urotensin II is an endogenous mitogen for some cells and the contribution of mitogenic effect of UⅡ to diseases deserves investigating greatly.

Abstract:Aim To investigate the role of angiotensin Ⅱ receptor antagonist losartan on the protein and mRNA expression of monnocyte chemoattractant protein 1 (MCP 1) in cultured rabbit aortic smooth muscle cells (SMC). Methods The levels of protein and mRNA expression of MCP 1 in cultured SMC and the contents of MCP 1 in the cultured media of SMC were detected by cytochemistry,situ hybridization and enzyme linked immunosorbent assay. Results 10 -6 ～10 -10 mol/L angiotensin Ⅱ(ATⅡ) increased the levels of protein and mRNA expression of MCP 1 in the cultured rabbit aortic SMC in a dose dependent manner and the co)ntents of MCP 1 in the cultured media of of SMC (P<0.001). Losartan markedly reduced the protein and mRNA expression of MCP 1 in the cultured rabbit aortic SMC and the contents of MCP 1 in the cultured media of of SMC induced by ATⅡ. Conclusions Losartan may antagonist ATⅡ induced protein and mRNA expression and secretion of MCP 1 in the cultured rabbit aortic SMC,which might play an important role in preventing the early atherosclerosis and the restenosis after angioplasty.

Abstract:Aim To ascertain whether vascular smooth muscle cells inhibit vascular smooth muscle cell proliferation by autocrine or paracrine of growth inhibitors. Methods Conditioned medium from rabbit aortic smooth muscle cell was used in this study. The conditioned medium was filtered by cut off M.W. 100 kDa or 10 kDa (Millipore). Smooth muscle cell proliferation was assayed by the measurement of XTT (Boehringer Mannhein). Results Rabbit aortic smooth muscle cell conditioned medium inhibited smooth muscle cell proliferation, 50% smooth muscle cell conditioned medium achieved 45% inhibitory rate of smooth muscle cell proliferation. This inhibition activity substance is dose dependent, 56℃, 30 min heat stable and M.W.less than 10 kDa. Conclusions Rabbit aortic smooth muscle cell could inhibit smooth muscle cell proliferation by autocrine or paracrine growth inhibitors.

Abstract:Aim [WT5”BZ]To study the influence of thrombin on gene expression of platelet derived growth factor(PDGF) in cultured vascular smooth muscle cells and probe into the mechanism of proliferation of vascular smooth cells induced by thrombin . [WT5”HZ]Methods [WT5”BZ]Take the incoporation of 3 H-thymidine as the target to evaluate vascular smooth muscle cells proliferation; thrombin-induced expression of PDGF-A mRNA in the vascular smooth muscle cells was detected by RT-PCR, while PDGF-B mRNA expression by Dot blot hybridization. [WT5”HZ]Results [WT5”BZ]Thrombin remarkedly stimulated proliferation of SD rat vascular smooth muscle cells in a dose-depedent and a time-dependent manner; PDGF-A and PDGF-B mRNA was detected in quiescent cultured vascular smooth muscle cells in serum-free medium for 48 hours,the expression of PDGF-A mRNA was increased in VSMC after exposure to thrombin for two hours, and reachd a peak levels after 4～6 houres exposure to thrombin. The rising level of PDGF -A mRNA continued for 12 hours,and felt to the base level 24～48 hours afterwards. [WT5”HZ] Conclusion [WT5”BZ] Thrombin remarkedly stimulated proliferation of SD rat vascular smooth muscle cells in a dose-depedent and a time-dependent manner, thrombin-induced vascular smooth muscle cells proliferation was partially mediated by expression of PDGF- A mRNA.

Abstract:Aim [WT5”BZ]To investigate the protective effect of Panax Notoginseng Saponins (PNS) on the cultured aortic smooth muscle cells (SMC). [WT5”HZ]Methods [WT5”BZ]In this study, cell culture technique was used in vitro. The protective effect of PNS on the proliferation of SMC was observed by measuring MTT metabolism and cell numbers and observing cell ultrastructure under TEM. [WT5”HZ]Results[WT5”BZ] The serum hyperlipidemia caused the increases in cell numbers and MTT metabolism of SMC. Under TEM, there are numerous rough endoplasmic reticulum and mitochondria and lipids in the cytoplasm of the cells cultured by serumof hyperlipidemia. The PNS can inhibit the proliferation of SMC dose dependently and can inhibit the proliferation of SMC stimulated by serumof hyperlipidemia significantly. [WT5”HZ]Conclusions[WT5”BZ] The PNS may prevent atherosclerosis and inhibit progression of the atheroslerotic lesions by interfering with the proliferation of arterial SMC.

Abstract:Aim To investigate the effect and significance of glucose and insulin on phospholipase A 2 (PLA 2) activities of vascular smooth muscle cells(VSMC). Methods VSMCs in rats were incubated with the DEME which had different concentration glucose or/and insulin for 72 h PLA 2 activities were detected with [ 3 H]-Oleate radioactivity(cpm). Results PLA 2 activities increased with high concentration of glucose or/and insulin and there were dose-dependent relationship. Conclusion The increased PLA 2 activities were associated with atherosclerosis in diabetes, so treatment with PLA 2 inhibitor could prevent the pathological progress of athcrosclerosis in diabetes.

Abstract:Aim and Methods Endothelin 1 (Et-1) is a potent vasoconstriction peptide which was firstly isolated from the conditioned medium of porcine aortic endothelial cells. Hypoxia can induce Et-1 gene expression in rat lung tissue and pulmonary artery. In order to assess the role of Et-1 in processes of pulmonary vasoconstriction and pulmonary vessel remodeling induced by hypoxia, the effects of ET-1 on contraction of pulmonary artery in rat and proliferation of pulmonary arterial smooth muscle cells in cultured of rabbit are investigated. Results ET-1 at concentrations ranged from 1× -9 to 12×10 9 mol/L caused-depended contration of vessel rings of rat pulmonary artery (r=0.935,P<0.05). When rabbit pulmonary arterial smooth muscle cells were cultured in the presence of 0.5% fetal calf serum (FCS), ET-1 at concentrations ranged from 1×10 11 to 1×10 -8 mol/L also stimulated 3 H-thymidine and 3 H- leucine incorporation in confluent quiescent monolayers in a dose-dependent manner (r=0.756 and 0.840, respectively), with EC50 being 10.87 nmol/L and 8.54 nmol/L. Conclusion Endothelin-1 may play a certain role in the hypoxic pulmonary hypertension.

Abstract:Aim To investigate the effects of phosphatidylinositol 3-kinase (PI3K)/protein kinase C-ζ (PKC-ζ)complex on regulating angiotensin Ⅱ(AngⅡ) activation of p70 ribosomal S6 kinase (p70S6K) in vascular smooth muscle cells(VSMC). Methods VSMC isolated from 200 g to 250 g male Sprague-Dawley rats were cultured to 70% to 80% confluence and were growth-arrested by incubation in 0.1% calf serum/DMEM for 48 h before use. Both 3 H-TdR incorporation and cell counting were used to estimate the proliferation of VSMC. Western blot, immunoprecipitation and immunoblot analyses were performed to valuate the AngⅡ-stimulated kinase expression and Ras-PI3K-PKC-ζ association of VSMC. Phosphotransferase assay by using S6 peptide as substrate was employed to measure the p70 S6K activity. Results VSMC expressed p85PI3K, PKC-ζ and p70S6K; AngⅡ and PDGF stimulation did not affect the p85PI3K, PKC-ζ and p70S6K expression. 2) 100 nmol AngⅡ

Abstract:Aim The effects of tetramethylpyrazine (TMP) on vascular smooth muscle cells (VSMC) proliferation were studied. Methods A cells proliferating model of rabbit aorta VSMC induced by thrombin were established; the effect of tetramethylpyrazine on c-myc gene expression in VSMC was observed by immunocytochemical method; the effect of tetramethylpyrazine on proliferation cycle of VSMC was observed by flow cytomytry technique. Results the highly expression of c-myc gene protein induced by thrombin can be inhibited by tetramethylpyrazine significantly, and the cells numbers of G1 phase were increased and the cells numbers of G1+M phase were decreased markedly. Conclusion The VSMC proliferation induced by thrombin can be inhibited by tetramethylpyrazine significantly, and the inhibited c-myc gene expression may contribute to the explanation of one of the mechanism of the inhibited VSMC proliferation.

Abstract:Aim To explore the molecular mechanisms of cultured rat vascular smooth muscle cell (VSMC) migration stimulated by newborn calf serum (NCS) or basic fibroblast growth factor (bFGF) and the mechanism of heparin inhibition on VSMC migration induced by NCS. Methods Rat osteopontin cDNA probe was amplified by RT PCR. After hydroxyurea inhibited VSMC proliferation induced by bFGF and NCS, osteopontin gene expression and cell energy exchange were respectively analyzed by Northern blotting and creatine kinase NAC kit. Results Northern blotting results showed that bFGF and NCS could induce VSMC osteopontin gene expression. However, heparin could inhibit osteopontin gene expression induced by NCS. Creatine kinase activity in VSMC stimulated by bFGFand NCS increased by 76% and 61%, respectively, as compared with that of the control (P<0.05), and creatine kinase activity of the NCS+heparin group was 22% lower than that of the NCS group. Conclusion VSMC migration stimulated by NCS or bFGF and heparin inhibition on VSMC migration induced by NCS were related with osteopontin gene expression and increased energy exchange.