| Objective:To establish diabetes mellitus and diabetic retinopathy animal models on Wistar rats, and discuss effect of diabetic retinopathy on EPCs. To analysis the role of EPCs in pathogenesis of DR, and explore new ideas, provide a theoretical basis for the treatment of DR.Methods:Sixty weight between 250g to 350g,2 month old, male Wistar rats were involved in this study. Twelve rats was randomly selected as control group were given intraperitoneal injection withcitral-natrium citricum buffer solution, and the other 96 eyes of 48 rats as experimental group were given intraperitoneal injection with streptozotocin (STZ). According to different time points after injection,24 rats were divided into one week, one month, three month and six month groups,12 rats in each group. Blood glucose concentration, body weight and EPCs were tested at different time points in all rats. Flow cytometry was used to identify and count the number of EPCs from peripheral blood. All eyeballs were examined by HE dying, retinal vessels stretched preparation PAS staining and transmission electron microscop. Statistical analysis was used to analyze the data.Results:1.Seventy-two hours after intraperitoneal injection of streptozotocin, glucose (fasting glucose greater than 16.65mmol/L) level reached the standard model. One week after injection, rats drinking more, eating more, and more urinary symptoms, body mass decreases, which was similar to the symptoms of diabetic. The rats in control group appeared drinking less water per day, less urine output, having much more smooth fur, body mass increases steadily with the time pass by. Compared with the blood glucose of rats in control group, those in 1 week,1,3,6 month after intraperitoneal injection of STZ groups were significantly different (P<0.05), so were their weight (P<0.05).2.EPCs count by flow cytometry:The number of EPCs from peripheral blood in one week, one month, three month, six month and control groups were 25±7,28±8,39±7,43±7,45±4 respectively. Compared with the control group, EPCs in experiment groups were decreased. The number of EPCs was gradually increased in 1 week,1,3,6 month groups. EPCs count in peripheral blood were sifnificantly different among those groups (P<0.05).3.HE staining:There was no obvious different changes in retinal layers among the control group,1 week group and one-month group. In 3 month group, the thickness of retinal layers began to reduce obviously, in a disorder arrangement, with vasodilatation. In 6 month group, the retinal layers became thinner, in a much more obvious disorder arrangement, with more pronounced vasodilatation, and even a trend of protrude and rupture. The thickness of retina in early DR rats was reduced. The number of retinal ganglial cells reduced, with the time pass by.4.Retinal vascular Digest Preparations:Inl week group, thickness of retinal capillary network diameter was uniform, cell nucleus of endothelial cells was in a shape of long oval, pale staining. Pericyte was round and stained deeply. In 3 month group, cell nucleus of pericyte in retinal capillary was similar to the normal group, with slightly larger size of individual nuclei, stained slightly, capillary lumen patency. In 6 month group, it appeared nucleus swelling in retinal capillary, the volume increases, dyeing slightly, obstruction of focal PMN in the lumen of capillaries, with atresia capillaries occasionally.5.Transmission electron microscopy detection:In 1 month group, capillary endothelial cells and nuclear membrane of pericyte were mild introcession, heterochromatin clustered and margination, the lumen is not deformed; The ridge of mitochondria was clear, some mitochondria in homogeneous solution. In 3 month group, endothelial cells were edema, nuclear chromatin clustered and margination, the lumen has no significant deformation; There were a great quantity of vacuolus in the inner plexiform layer, mitochondrial was swollen, cristae was disappeared, the capillary basement membrane was thicken, the electron density significantly increased. In 6 month group, endothelial cells were edema and deformed, nuclear chromatin clustered and margination, the nuclear was deformed, the mitochondria was swollen, vacuolar degeneration was shown. The capillary basement membrane was thicken, the electron density significantly increased; endothelial cell cytoplasm was finger-like processes to the lumen, which has significant stenosis and even occlusion. In ganglion cell layer, ganglion cells in the nucleus can be seen depression, with the formation of false packet ring body. Golgi vesicle was expanded. Conclusions:1. One week after intraperitoneal injection of STZ, a stable diabetic rats'model was established.2. The change of DR was occurred 1 week,1,3,6 month after intraperitoneal injection of STZ and the degrees were aggravated gradually with time pass by.3. The count of EPCs after injection was decreased. The number of EPCs was gradually increased in 1 week,1,3,6 month groups.4. EPCs maybe plays an important role in the pathogenesis of diabetic retinopathy. The mobilization and survival time of EPCs lead to impaired process of vascular re-endothelialization, and accelerated the development of ischemic disease. EPCs involved in the process of DR.5.Analysis the role of EPCs in pathogenesis of DR, and explore new ideas, provide a theoretical basis for the treatment of DR. |
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