| Diabetic retinopathy (DR) is a vasoproliferative disorder of the retina. It is one of the major causes of blindness worldwide. Today, there is an increase in DR due to the fact that the quality of life is advanced in recent years in our country. So far, the exact pathogenesis is not clear, but it is proved by many researches that the regulation of enzymes, kinases, various sorts of growth factors, inflammation and immunological reaction play important role in the process of retinal vascularization. In the present study, we investigated the expression and distribution of erythropoietin (EPO), growth related oncogene-alpha (Gro-a), delta-like 4 ligan- Notch (D114/Notch-1) in retinas of diabetic rats.Part I Investigation of concentration of erythropoietin and growth related oncogene-alpha in plasma and vitreous body in patients with diabetic retinopathyObjective:To measure the concentration of erythropoietin (EPO) and growth related oncogene-alpha (Gro-a) in plasma and vitreous body in patients with diabetic retinopathy(DR) and find the role they play in the development of DR.Methods:It was a case-control study. Patients were divided into three groups: non-proliferative diabetic retinopathy group (NPDR), proliferative diabetic retinopathy group (PDR) and control group. The concentration of EPO and Gro-a in plasma and vitreous was measured by ELISA.Results:The concentration of EPO in plasma was (22.16±4.85) mIU/ml in NPDR group, (25.46±8.83) mIU/ml in PDR group, and (23.52±7.27) mIU/ml in control group; The concentration of EPO in vitreous body was (461.36±101.20) mIU/ml in PDR group and (36.78±10.19) mIU/ml in control group. The concentration of Gro-a in plasma was (81.95±38.08) pg/ml in NPDR group, (82.61±25.26) pg/ml in PDR group, and (55.68±22.53) pg/ml in control group; The concentration of Gro-a in vitreous body was (327.74±216.29) pg/ml in PDR group and (81.95±47.59) pg/ml in the control group. In plasma, there was no significant difference among the three groups in EPO concentration (P>0.05), but in Gro-a there was significant difference (P<0.05).In vitreous, there was significant difference between the two groups in both EPO and Gro-a(P<0.05). Positive correlation was found between EPO/Gro-a and HbAlc(%) in plasma and vitreous.Conclusions:For patients with PDR, the concentrations of Gro-a in plasma, EPO and Gro-a in vitreous body increase significantly, and the concentrations correlate with the value of HbAlc(%).Part II The expression of GRO-a, EPO in the retina of diabetic rats and the effect of celecoxib on the expression of EPO and GRO-aObjective:To investigate the expression of EPO/GRO-a and the effect of celecoxib on the expression of EPO and GRO-a in retina of diabetic rats.Methods:Forty healthy male SD rats were chosen and divided randomly into 4 groups: normal control group, diabetes group (DM, n=10),diabetes+distilled water group, diabetes+ celecoxib group, with 10 rats in each group. Diabetes were induced by a single intraperitoneal injection of streptozotocin (STZ) (50mg/kg).All of the rats were executed 3 months later. The expression of COX-2, VEGF, EPO and GRO-a mRNA was evaluated by real-time SYBR Green fluorescent quantitative polymerase chain reaction Western blot was used to examine the expression of COX-2, VEGF, EPO and GRO-a protein.Results:After 3 months, the expression of COX-2, VEGF, EPO and GRO-a (mRNA /protein) was significantly increased in diabetes group and diabetes+distilled water group (compared with the normal group. The expression of COX-2,VEGF, EPO, GRO-a mRNA/protein was significantly deceased in diabetes+ celecoxib group (compared with diabetes+distilled water group). However, The expression of COX-2,VEGF,EPO, GRO-a mRNA/protein was still increased (compared with the normal group.)Conclusion:EPO, GRO-a may play an important role in diabetic rats, celecoxib can decrease the expression of EPO and GRO-a, and then inhibit the retinal the expression of VEGF.PartⅢThe effect of celecoxib on the expression of dll4 and Notch-1 in the retina of diabetic ratsObjective:To investigate the effect of celecoxib (a selective cyclooxygenase-2 enzyme inhibitor) on the expression of delta-like 4 ligan-Notch (D114/Notch-1) in retinas of diabetic rats.Methods:Forty healthy male SD rats were chosen and randomly divided into 4 groups: normal control group, diabetes group (DM,n=10), diabetes+distilled water group and diabetes+celecoxib group. Diabetes were induced by a single intraperitoneal injection of streptozotocin (STZ)(50mg/kg). All of the rats were executed after 12 weeks intraperitoneal injection of STZ. The expression of Cyclooxygenase-2(COX-2), vascular endothelial growth factor (VEGF), Notch-1 and D114 mRNA was evaluated by real-time SYBR Green fluorescent quantitative polymerase chain reaction. Western blotting was used to examine the expression of COX-2, VEGF, Notch-1 and D114 protein.Results:After 12 weeks, the expression of COX-2, VEGF, D114 and Notch-1 (mRNA /protein) was significantly increased in diabetes group and diabetes+distilled water group (compared with the normal group). The expression of COX-2 and VEGF mRNA/protein was significantly deceased in diabetes+ celecoxib group (compared with diabetes+distilled water group. However, The expression of Notch-1 and D114 mRNA/protein was increased in diabetes+celecoxib group (compared with diabetes group and diabetes+distilled water group)Conclusion:Notch-1 and D114 play an important role on retinal angiogenesis. The selected inhibition of COX-2 can increase the expression of Notch-1 and D114 mRNA/protein and then inhibit the VEGF expression in retina of diabetic rats. |
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