Intravitreal fibrin clots were produced by intravitreal injection of 0.2 ml autologous plasma in 18 rabbit eyes. Subsequently these eyes were treated by intravitreal injection of either tissue plasminogin activator(t-PA) or saline. In the t-PA(12.5mu;g) group(n=10),intravitreal fibrin clots of 6 eyes cleared up within 6 hours, and that of the other 4 eyes within 1 day. In the saline group( n=7), the complete clearallce was not seen after 7 days. The difference of time between two groups was significant ( P＜0. 05), and no evidence of toxic effect was observed as measured by slit-lamp biomicrocopy, ERG, light microcopy and transmission electron microscopy.One eye treated with 100mu;g t-PA also resulted in a total clearance within 6 hours,but retinal toxicity was demonstrated with ophthalmoscopy and light microscopy. （Chin J Ocul Fundus Dis,1994,10:14-16）
Abstract: Objective To investigate the messenger ribonucleic acid (mRNA) expression level of tissue-type plasminogen activator (t-PA) in endothelial cells derived from adult mesenchymal stem cells (MSCs) after fluid shear stress loading which is within the physiological range. Methods After culturing in vitro, bone marrow MSCs of SD rats were seeded on slides.When it come to 80% confluence,26 slides were exposed to 5dyn/cm2 fluid shear stress for 3h in a flow chamber, and then induced to endothelial cells. Among them,13 slides constituted group Ⅰ, and the rest 13 slides set up group Ⅱ, which would be cultured for 3-4d further and passaged in 1∶3. At the same time, control group was set up, which including the cells never exposed to fluid shear stress before the endothelial differentiation. Fluid shear stress were exerting to cells in a specially made flow chamber. The expression level of t-PA mRNA of all groups were measured by real-time fluorescent quantitation reverse transcriptionpolymerase chain reaction (RTPCR). Results After endothelial differentiation for 7 days, the SD rats bone marrow MSCs acquired typical endothelial cell appearance. The t-PA mRNA expression level of group Ⅰ and group Ⅱ have an obviously enhance compared with control group(P＜0.05). The t-PA mRNA expression level of group Ⅱ step down a little (P＞0.05), but it is still significantly higher than that of control group (P＜0.05). Conclusion Fluid shear stress could provide a protective action on the endothelial cells induced from MSCs in vitro, and the effect maintains with the cells passages. This formulates a theoretical foundation to the therapeutics of atherosclerosis and selection of seed cells in vascular tissue engineering.
Objective To explore the effect of xue-shuan-tong(panax notoginsang saponins,PNS)or isovalaemic haemodilution(IHD)and PNS combining IHD treatment on activities of fibrinolysis and hemorrheology in patients with retinal vein occlusion (RVO). Methods Seventy-three patients with RVO were allocated at random to 3 groups which were treated with PNS,IHD and PNS combining IHD.The activities of t-PA and PAI,rheological parameters and visual acuity before and after treatment were observed. Results At the end of treatment,significantly increased activity of t-PA and decrease of PAI was found in combined treatment group and PNS group,but the difference before and after treatment was not significant in IHD group.Furthermore,except the plasma viscosity in IHD group,the other hemorrheological parameters in all the petients of 3 groups revealed to be improving.One month after treatment,the parameters return completely to normal in both PNS and IHD groups; while the whole blood apparent relative viscosity in low shear rate,RBC aggregation and RBC deformability maintained still in lower level,and also the visual acuity resumed better and quicker in combined group. Conclusion Combined treatment of PNS and IHD can both regulate the activity of fibrinolysis and decrease the blood viscosity of patients with RVO for a period of relatively long time and increase the effect of treatment. (Chin J Ocul Fundus Dis,1998,14:7-9)
Objective To reveal the fibrillar network in vitreous and the effect of plasmin on this network.Methods 20 vitreous gels of freshly slaughtered pigs were divided into 2 groups, the gels in first group were digested by 3 Uplasmin (3 U/ml) at 37c for 24 hours respectively, the second group received the same PBS as control. After digestion, gels were fixed in neutral buffered formalin solution. Samples from vitreous base, cortex and the central region were observed by the technique of freeze etching electron microscopy.Results In vitreous collagen fibril network was in a three-dimensional array, collagen fibril density showed marked differences, central vitreous had the sparse fibril density, the cortex denser and the basal vitreous densest. After digestion by plasmin, the collagen fibrillar network was destructed.Conclusion Collagen fibrils in vitreous present spatial arrangement regularly, plasmin can lead to destruction of the fibrillar network.(Chin J Ocul Fundus Dis，2003，19：179-181)
Objective To observe the inhibitory effects of local co-transfection of tissuetype plasminogen activator(tPA) gene and proliferating cell nuclear antigen antisense oligodeoxynucleotides(PCNA-ASODN) on the intima proliferation and restenosis of autograft artery in rabbits. Methods One hundred and twenty male Zelanian rabbits were randomly divided into four groups(n=30, in each group): control group, PCNA-ASODN group, tPA group and tPA+PCNAASODN group. The left and right external iliac arteries (length 1.0 cm) were transplanted reciprocally. The transplanted arteries were respectively soaked in lipofection, PCNAASODN, pBudCE4.1/tPA and pBudCE4.1/tPA+PCNA-ASODN solution about 15 minutes. The transplanted arteries were sutured with 9-0 sutures soaked in PCNA-ASODN and pBudCE4.1/tPA solution. Each group were divided into five subgroups(n=6, in each subgroup) according to the sacrifice time (3 d, 7 d, 14 d, 28 d and 56 d after operation). On every sacrifice time point, the vascular specimens were harvested. The thrombocyte assembling and thrombus forming lining vessel wall were observed by scanning electron microscope. The pathological morphology of transplanted arteries were observed under microscope(HE). The intimal areas and stenosis ratio(%) of transplanted arteries were calculate and analyzed statistically among groups by computer system. The mRNA expression of tPA gene in transplanted ressel wall was detected with vevere transcriptionPCR(RT-PCR). The number of PCNA positive cells in transplanted vessel wall was counted by SP immunochemisty.Results The mRNA expression of tPA gene in the transplanted vessel wall in tPA and tPA+PCNA-ASODN groups was higher than that of the other two groups(P＜0.01).The number of PCNA positive cells in the transplanted arteries in PCNAASODN, tPA and tPA+PCNAASODN groups were significantly lower than that of control group(P＜0.05，P＜0.01). The intimal areas and degrees of luminal stenosis of PCNAASODN, tPA and tPA+PCNAASODN groups were lower than those of control group(P＜0.05，P＜0.01), and those of tPA＋ PCNA-ASODN group were lower than those of PCNA-ASODN and tPA groups(P＜0.05). Scanning electron microscopy showed that there were a few thrombocytes lining the vessel wall of tPA group and tPA+PCNAASODN group and no thrombus, whereas there were abundant thrombocytes and thrombi lining the vessel wall of the control group. Conclusion Co-transfection of tPA gene and PCNA-ASODN can effectively inhibit the proliferation of VSMC, hyperplasia of intima and restenosis of transplanted artery.
Objective To determine whether kringle 4-5 could inhibit choroidal neovascularization (CNV) in mice induced by argon laser photocoagulat ion. Methods Fundus laser photocoagulation was performed on C57BL/6J mice to induce CNV. In treatment group, 20 μg (low dosage group) and 50 μg (high dosage group) kringle 4-5 were injected retrobulbarly after photocoagulation. In control group, equilibrium liquid was injected retrobulbarly. Choroidal neovascularization was evaluated on the 7th and 14th day after photocoagulation by fundus fluorescein ang iography. The mice were killed on the 14th day after photocoagulation, the lesions were evaluated histologically and immunohistochemically, and the expression of CD105 was detected. The Expression of VEGF and bFGF was detected by immunohist ochemistry on the 4th day after photocoagulation.Results The incidence of CNV was 64.3% in control group, 51.2%（P＜0.05）in low dosage group, and 44. 1% (P＜0.01) in high dosage group. The CNV lesions were smaller in kringle 4-5 injected eyes in a dose-dependent manner and the number of proliferative vascular endothelial cells in the subretinal membrane of the treated eyes was smaller than that of the control eyes. There was no significant difference of the expression of VEGF and bFGF between the mice in control and treatment group.Conclus ions Kringle 4-5 could inhibit the development of choroidal neovascularization in the experimental mice model.(Chin J Ocul Fundus Dis，2003，19：201-268)
Objective To investigate the dosage, efficacy and safety of intrav itreal injection of plasmin in producing posterior vitreous detachment (PVD), an d the possible role of plasmin in degrading adhesion glycoproteins of inner limiting membrane (ILM).Methods Twenty eyes of young human cadavers within 24 hours after death were divided into 4 groups that received 0.1 ml balanced salt solution (group 1) as control, 1 (group 2), 2 (group 3), or 3 (group 4) U of human plasmin. Optical and transmission electron microcopies were performed to examine the ultrastructure of the vitreoretinal interface. Electron-immunocytochemical techniques were carried out on ILM to estimate the content of fibronectin (FN) and laminin (LN). Flow cytometry was used for cell viability analysis of variance (ANOVA) and Tukey-test was employed for statistical analysis. Results Microscopy demonstrated that plasmin especially in group 4 cleaved the attachment of the vitreous collagen fibrils to the ILM with no evident damage to the inner retina. The content of LN, FN in ILM decreased with injection of plasmin (group 3 and 4 had statistical significance from control group for FN,P＜0.05; for LN in group 4, P＜0.05). Retinal cell viability was similar for plasmin-treated and control eyes. Conclusion Human plasmin disrupts the attachment of posterior hyaloid to the ILM with no morphologic changes of the inner retina. PVD is induced mostly with injection of 3 U plasmin. (Chin J Ocul Fundus Dis，2003，19：42-45)