Study On The Apoptosis Of Diabetic Retinal Neurocyte And The Efficacy Of Aminoguanidine

[Objective] To observe the retinal ultrastructural changes and investigate the expression of apoptosis associated gene C-myc,apoptosis factor LaminB in the retina of diabetic rats and the effects of aminoguanidine .To study the pathogenesis of diabetic retinopathy and the therapeutical effect of aminoguanidine in early diabetic retinopathy.[Method] Wister rats were randomly divided into normal group, diabetic mellitus (DM) group and aminoguanidine (AG) group . Diabetes was induced in rats by the intraperitoneal injection of streptozotocin (STZ). The rats were killed separately after 1 , 3 and 6 months, we observe the ultrastructural changes in electron microscope and observe the cell apoptosis in fluoTescent microscope in the method of TUNEL. And the expression of C-myc LaminB was studied by strept avidin-biotin complex (SABC)immunohistochemistry.[Result] 1. DM1, Electromicroscope: DM1 month, cytoplasm appear asymmetry in the inner nuclear layer, the ganglion cells change is slight;DM3 month, nuclear condensation of visual cyte can be observed in the inner nuclear layer, and the changes appear in ganglion cells.; DM6 month, the changes aggravate and apoptotic body can be found in the inner nuclear layers. While in treatment of the same month the situation was better. 2. TUNEL: there were positive expression in 3 month group and more positive expression in 6 month group, and the TUNEL cells were in the ganglion cells and the inner nuclear layers.while in treatment group the positive expression was less to the rats in untreated group of the same month. 3. Immunohistochemistry : (1)expression of C-myc : No positive cells were observed in the normal retina. Positive expression of C-myc gradually increased in DM3 group and DM6 group .In DM3 group, positive expression of C-myc was found in ganglion cells and inner nuclear cells . In DM6 group, positive expression of C-myc increase. While in the same month of treatment group,the expression of C-myc was less (p<0.05) .(2) No LaminB positive cells were observed in the normal retina and in DM3 group . In DM6 group , the expression of LaminB increase in ganglion cell layer and inner nuclear layer. While in the same month of treatment group,the expression of LaminB was less(p<0.05).[Conclusion] the retina of diabetic rats changes in ultrastructure and apoptotic cells were found in the inner nuclear layers.Diabetes elevated the expression of C-myc ,LaminBin the retina. C-myc, LaminB may play a role in the early events of the diabetic retinal apoptotic pathway. Aminoguanidine may cure diabetic retinopathy through its inhibition on the expression of C-myc, LaminB in early diabetic retinopathy.