Experimental Study Of Vascular Endothelial Growth Factor And Thrombospondin-1 In The Diabetic Retinopathy

Objectives :To study the expression of VEGF and TSP-1 in the retinas of the early diabetic rats , approach the role of their balance in the diabetic retinopathy , thus provide a new idea for the clinical prevention and cure of the early diabetic retinopathy .Methods: select healthy male Wistar rats which were randomly divided into diabetic group and normal control group and were injected with large-dose STZ by intraperitoneal injection to induce the diabetic rat model. After model was succeeded, the diabetic rats were divided into one-month,two-month,three-month diabetic and drug-interfered groups on average . Sacrifice the rats and fix their eyeballs. Retina sections were stained by HE and retina tissue structure were observed by the light microscope; ultramicrostructure were observed by transmission electron microscope(TEM); the expression of VEGF and TSP-1 in the diabetic retinopathy was detected by immunohistochemistry.Results:1 From three-month diabetes , the retinas by HE stained in the light microscope begin to appear dropsy ,cells alinement disorder etal ,the pathological changes aggravate with the prolonged course of disease.2 From one month experimental diabetes, by transmission electron microscope(TEM) , The changes of DR have already begun. The pathological changes aggravate with the prolonged course of disease. There were significant deviation compared with control group(P<0.05).3 Immunohistochemistry : From three-month diabetes , the positive expression of VEGF was remarkably higher more than control group (P<0.05)。And the positive staining density of VEGF in retina increased gradually with the prolonged course of disease(P<0.05), but only in three-month group of drug-interfered ,the expression of VEGF was lower than three-month diabetic group.4 The positive expression of TSP-1 was seen in normal control group ,the expression of TSP-1 in every diabetic group was lower than normal control group(P<0.05), the expression of TSP-1 decreased with the prolonged course of disease(P<0.05),but only in three-month group of drug-interfered ,the expression of TSP-1 increased than the three-month diabetic group.Conclusions:The diabetic rat retinopathy model induced successfully by STZ can be used in the relevant study of early DR .The changes of diabetic diabetic retinopathy is more obvious with the development of course of diseases. In the early diabetic retinopathy , VEGF plays an important role in neovascularization.TSP-1 takes in part in the early DR, and it's expression decreases with the development of diabetic retinopathy, which clews that the deficiency of TSP-1 may be one of important causes in DR.In a word, this expreriment combands morphology with molecular biology, and approaches the expression of VEGF and TSP-1 in DR, and provides theory evidence to prevent and cure the DR in the early period from molecular level.