Objective To observe whether theograde axial flow of retinal ganglion cells (RGC) in diabetic rats at the early stage was damaged. Methods Diabetic model was induced by streptozotocin in 6 adult male Sprague-Dawley (SD)rats. Fluorogold (FG) was injected to the superior colliculi 4 weeks later.Streched preparation of retina was made 12 and 72 hours after the injection, and was stained after photographed by fluorescent microscope. The proportion of RGC with different sizes labeled by FG was calculated. Other 6 normal adult male SD rats were in the control group. Results Twelve hours after injection with FG, there was no difference of the total number of RGC in experimental and control group, but the ratio of small RGC was lower in experimental group than that in the control group; 72 hours after injection with FG, The number of RGC, especially the small RGC, decreased obviously in experimental group compared with the control group. Conclusion The speed of the retrograde axial flow of RGC in diabetic rats at the early stage is affected, and the small RGC are damageable. (Chin J Ocul Fundus Dis, 2006, 22: 4-6)
ObjectiveTo observe the effects of Rhodiola on the rat retinal tissue morphology and the hypoxia-inducible factor (HIF)-1α at simulated hypoxia at different altitudes. Methods Forty-eight adult female Sprague Dawley rats were randomly divided into the Rhodiola Intervention group (intervention group) and the control group, each group had 24 rats. The intervention group rats were treated with intraperitoneal injection of 10 ml/kg of large plants Rhodiola solution, and the control group rats were injected with same volume of saline. One hour after the injection, six rats were randomly selected from both of the two groups and reared in the plateau environment simulation laboratory modules with the oxygen partial pressure of 17.4, 14.6, 11.3 and 7.4 kPa, which simulated the altitudes of 1500, 3000, 5000 and 8000 meters indoor respectively. Six hours later the rat eyeballs were harvested for paraffin sections and analyzed by hematoxylin and eosin staining, and immunohistochemical staining to observe the expression of HIF-1α and p53. ResultsIn the control group, the rat retinal layers were edema and loose, the retinal thickness increased, the retinal structure was disorganized, the ganglion cells were swollen and degenerated, and some can observe the karyopyknosis, karyolysis and the reduced cells number. As the altitude increased, the pathological changes of retinal became more obvious. In the intervention group, the characteristics of rat retinal morphology were same with the control group, while the degree of morphology changes was lighter than the control group. HIF-1α and p53 expressed mainly in the ganglion cell layer and inner nuclear layer of rat retina in the control group. As altitude increased, the expression of HIF-1α and p53 were increased too, which was positive correlated (r=0.9846, P < 0.05). Compared with the control group, the rat retinal expression of HIF-1α increased, while expression of p53 decreased in the intervention group, and the differences were statistically significant (P < 0.05). ConclusionRhodiola can reduce the retinal tissue pathology damage caused by high altitude hypoxia, and its mechanism may be related to the increasing expression of HIF-1α and reducing expression of p53.
Objective To observe the morphological changes of dendrite and soma in retinal ganglion cells (RGCs) which subsisted in early diabetic rats. Methods The RGCs of 3-months-course diabetic rats and coeval normal rats were marked by gene gun techniques. To collect RGCs photographs by Leica microscope with Z axis and CCD camera；to observe the changes of diameter, variance of structural features in dendritic field and somata after classification which according to the size and morphology. Thy-1 antibody marks on the retinal RGCs, taking a photograph under fluorescent microscope, counting the changes of retinal RGCs density in early diabetic rat. Results In three-month diabetic rats,the density of retinal RGCs was decreased obviously. Morphological changes of RGCs in the dendritic fields were observed with gene gun technique. There was no severe variation in all kinds of the bole of cell dendrite, in which some only showed crispation partially and sparseness also twisting in the dendritic ramus. The mean diameter of dendritic field and soma in class A of diabetic rats was (401plusmn;86) mu;m, the mean diameter of dendritic field in control group was (315plusmn;72) mu;m,compared with each other, there is statistically significant differences (t=21.249，Plt;0.001); the mean diameter of soma in class A of diabetic rats was (24plusmn;6) mu;m, the mean diameter of soma in control group was (22plusmn;5) mu;m, compared with each other, there is no statistically significant differences (t=0.927，Pgt;0.05); the mean diameter of dendritic field and soma in class B of diabetic rats were (170plusmn;36)、(14plusmn;2) mu;m respectively, in control group were (165plusmn;36)、(16plusmn;2) mu;m, the mean diameter of dendritic field and soma in class C of diabetic group were(265plusmn;78)、(17plusmn;5) mu;m respectively, in control group were (251plusmn;57)、(17plusmn;4) mu;m , compared with each other, there are on statistically significant differences(t=1.357，0.798，0.835，1.104，Pgt;0.05). Conclusions In short-term diabetes, the survived RGCs show good plasticity in adult diabetic rats, especially in class A. The changes of dendrites were more sensitive than the soma, which could be the leading index of the morphologic changes of RGCs in the early stage. The good plasticity showed by the RGCs and the time window from changing in dendrite to cell death provide us many evidences not only for the research but also for the nerve protection in clinic. (Chin J Ocul Fundus Dis,2008,24:249-254)
Objective To investigate the effect of pigment epitheliumderived factor (PEDF）on the expression of glutamine synthetase in retinal Muuml;ller cells of diabetic rats.Methods Diabetic rats were induced with streptozotocin injection.Before and after injection of 10 mu;l (0.1 mu;g/mu;l) PEDF (experimental group) or 10 mu;l PBS (control group) into the vitreous cavities of diabetic rats respectively for 48 hours,the expressions of GS and IL-1beta; in retina were analyzed by immunohistochemistry and real time RTPCR techniques. After being treated with 100 ng/ml PEDF for 24 hours in high glucose conditions,the expressions of GS and IL-1beta; in cultured Muuml;ller cells were studied by western blot and real time RT-PCR techniques. Apoptosis was analyzed by flow cytometry after Annexin V fluorescein isothiocyanate/Propidium idoium (Annexin V-FITC/PI) staining.Results By immunohistochemistry (the protein level) and real time RT-PCR (the mRNA level),it was found that the expression of GS decreased and the expression of IL-1beta; increased obviously (real time RT-PCR：GS:t=4.23,P＜0.01；IL-1beta;:t=16.73,P＜0.01；immunohistochemistry：GS: t=5.13,P＜0.01；IL-1beta;:t=9.32,P＜0.01) in diabetic rats. After injection of 10 mu;l (0.1 mu;g/mu;l) PEDF into the vitreous cavities of diabetic rats for 48 hours,it was found that the expression of GS increased and the expression of IL-1beta; decreased significantly(RT-PCR GS:t=3.87,P＜0.01IL-1beta;:t=3.61,P＜0.05;immunohistochemistry:GS:t=3.32, P＜0.05；IL-1beta;: t=2.63,P＜0.05). Under high glucose conditions, 100 ng/ml PEDF induced decreasing expression of IL-1beta; and increasing expression of GS significantly (RT-PCR：GS: t=2.89, P＜0.05；IL-1beta;: t=3.37,P＜0.05；Western blot：GS:t=2.66,P＜0.05;IL-1beta;:t=3.23,P＜0.05).Apoptosis of Muuml;ller cells under high glucose conditions was inhibited significantly by the treatment with 100 nmol/ml PEDF (t=3.21,P＜0.05). Conclusions In diabetic rats,PEDF may decrease expression of IL-1beta; in rat retinal Muuml;ller cells, which may result in increasing expression of GS.To some degree,it inhibits possibly the death of retinal ganglion cells.
Purpose To investigate the clinical features and pathogenesis of acute posterior multifocal placoid pigment epitheliopathy(APMPPE). Methods To observe the features in 8 eyes of 6 cases of APMPPE with fundus fluorescein angiography(FFA) and indocyanine green angiography(ICGA).One of the cases had been observed continuously for 160 days. Results 1.FFA: at the acute stage of APMPPE,the affected foci showed low fluorescence in the early phase and stained gradually in 3 eyes;the fluorescence of recessive foci were still lower in 4 eyes,and the stale one showed window defect fluorescence due to some RPE fading and fluorescence sheltering due to pigment deposit.2.ICGA:at acuted stage,the fluorescence of choroid lobules was ofen defected untill in late period of pathogenical changes. Conclusion The findings demonstrate the obstruction of choriocapillaries may be the primary pathogenesis of APMPPE. (Chin J Ocul Fundus Dis,1998,14:84-87)