The Mechanism Of Action Of P38 Mapk Signaling System In Diabetic Retinopathy Experimental Research

PART 1 EFFECTS OF HIGH GLUCOSE CONCENTRATION ON P38MAPK SIGNAL SYSTEM EXPRESSION IN CULTURED HMAN UMBILICAL VEIN ENDOTHELIAL CELLSObjective: We detected the effect on p38 mitogen-activated protein kinase(p38 MAPK) signal system expression with high concentration glucose in cultured human umbilical vein endothelial cells , in order to approach the role of p38 MAPK signal system in diabetic retinopathy induced by high concentration glucose.Methods: Adopted cultured human umbilical vein endothelial cells as the research object, excited HUVEC with high concentration glucose in the condition of analogued diabetes. Detected the variation of p38MAPK,transforming growth factorβ2 (TGFβ2),matrix metalloproteinase-2 (MMP-2) activity and protein expression with RT-PCR and Western-blot. Observed the ultramicrostructure with electron microscope and detected the alternation of cell cycle with flow cytometry.Results: Expression of p38MAPK,MMP-2 and TGFβ2 increased , ultramicrostructure and cell cycle altered in endothelial cell with high concentration glucose.Conclusions: p38MAPK signal system expression increased was possible to participate the pathogenesy of diabetic retinopathy induced by high concentration glucose. PART 2 THE ALTERNATION OF P38MAPK SIGNAL SYSTEM EXPRESSION IN RETINA OF EXPERIMENTAL DIABETES HAMSTERSObjective: To explore the role and mechanism of p38MAPK signal system in the onset and development of diabetic retinopathy (DR) by detecting the alternation of p38MAPK signal system expression in retina of experimental diabetes hamsters.Methods: Hamsters were used to induce diabetic models by Streptozotocin (STZ 40mg/kg), morphologic characteristics and changes of retina was observed by HE staining, and ultramicrostructure of retina with electron microscope, detected the expression of TGF-β2 in retina with immunohistochemical method between normal control group and diabetes animal model group. The changes of triglyceride (TG),cholesterol total (TC) were tested serologically and insulin were tested by electrochemiluminescence.Total RNA of retina was collected. The expression of p38 MAPK,MMP-2 and TGFβ2 mRNA in retina was observed by using semi-quantitative RT-PCR , and the expression of protein of p38 MAPK,MMP-2 and TGFβ2 with Western-blot in retina of diabetes hamsters.Results: Diabetes hamsters not only showed hyperglycaemia, but also hyperlipemia. The reaction for TGF-β2 was negative in normal retina. However, TGF-β2 did express in the retina of diabetic hamsters. Ultrastructure made evident changes. Membranous disc structure delaminated and quantity was rare; ganglionic layer endocytoplasmic reticulum broadened, perinuclear space enlarged, mitochondria engorged and so on. The quantity of p38 MAPK,MMP-2,TGF-β2 mRNA and protein expressed more than the normal control group in retina of diabetes hamsters and the difference between the experiment group(16w) and the normal control group had statistical significance(P<0.05).Conclusions: This experiment provides the basements of p38 MAPK signal pathway which participates in the pathogenesy of DR.