| Diabetes characterizes the sweet metabolism turbulence, which causes many ocular complications. Among them, DR is the most serious. In normal ocular tissues, angiogenic nomeostasis is controlled by the balance between angiogenic stimulators, such as VEDF and angiogenic inhibitors, such as PEDF. The balance between angiogenic stimulators and angiogenic inhibitors leads to DR formatting and developing under pathological condition. VEGF is the most potent angiogenic stimulator, which can stimulate vascular endothelial cell proliferation and migration and induce retinal neovascularization. Many studied showed that VEGF plays an important role in retinal neovascularization, especially under hypoxia. PEDF was first identified as RPE - derived protein with potent incuronal differentiating activity. Study showed that RPE cell could secret PEDF in vivo and in vitro. At the same time, PEDF is an effective angiogenesis inhibitor and could inhibit endothelial cell migration during the neovasculation. Retinal neovascularization is induced by the combing effect of angiogenesis (PEDF) decreasing and angiogenesis stimulators increasing. At present, there are many researches about the pathogenesis of DR and related elements, but no related reports about the dynamic change of VEGF and PEDF, the two antrary factor during DR generating and developing. So we induced diabetes rat models and detected the dynar-mic change of VEGF and PEDF mRNA expression at one month, two months and six months, respectively to investigate the relationship between its change and DR.Material and methods: 1. animal grouping and preparing diabetes rat model. Rat: 48 male WISTAR rats about 12 weeks, weight 180-220g. The rats were divided into normal control (CON1,CON3, CON6) , diabetes for 1 month (DM1) , 3 months (DM3) , 6 months ( DM6). The rats were injected 2% STZ according to 60mg/Kg through abdominal cavity and detected the blood the blood sugar and urine sugar after a week. The rats were considered as diabetes rats if its urine sugar exceeded + + + and blood sugar exceeded 16. 7mmol/L. 2. methods: Executing 8 CON, DM1, DM3 and DM6 rats respectively and taking out eyes instantly. The left eyes were used to prepare digestive extend slide and stained with PAS routinely. Selecting five fields of vision at random at microscope and calculating the number of circuit cells and endotherial cell. The right eyes were fixed with 10% polyformalin in situ hybridization the next day. Selecting five fields to calculate the positive cells and performed quality and semi - quantitive analysis at random with microscope.Results: A: The morphology observation of Retinal digestive extend slides. 1. Quality observation; observation the retinal vascular morphology change of the normal rats. (1) Observation the integrated vascular net, the retinal capillary is the same diameter. ( 2 ) There were two kinds of cells, one was endotherial cells in the center of the blood vessel with large nucleus and weak stain; the other was circuit cells with strong stain. There were morphological change of the retinal vascular of the diabetes rats. (1) capillary became circuitous and roughly with irregular marchiny. (2) the diameter was the same various. ( 3 ) AU the change was the most obvious at 6 months and there was longer capillary without tube. 2. Observation; the circuit cells significantly quantitive observasion with the increasing of the disease duration. The circuit cells at 6 months were significantly less than that of the rats in 1 month and 3 month and also less than that of the normal control.There were no significant difference of the number of the endotherial cells between different group rats and different disease duration. B; Expression of VEGF and PEDF mRNA: The expression of VEGF mRNA of the 1 month rats was no significant difference compared with the control. The VEGF mRNA only expressed at ginant cells and inner nuclear. Besides, inner nuclear and ginant cells RPE lay expressed a little VEGF mRNA, too at 3 months. There more positive cells at inner nuclear... |
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