Impairment Of Retinal Ganglion Cells In The Short-term Diabetic Rats

Purpose. To study the early impairment of retinal ganglion cells (RGCs) in the short term streptozotocin (STZ)-induced diabetic rats. The morphological changes of RGCs and their dendrites position in the inner plexiform layer were examined and the retrograde axonal transport abilities of different kind of RGCs were evaluated. Method. 1) The Sprague-Dawley (SD) rat model of STZ-induced diabetes was combined with gene gun techniques to label the somata and dendritic fields of RGCs in the isolated retinae in detail. Data from three types of RGCs were collected and compared using a Leica DMRA microscope equipped with a spot cooled CCD camera. 2) Flurogold (FG) was injected into the superior colliculi in adult SD rats 4 weeks after diabetes induced by STZ.12 hours, 3 days (3d) and 7 days (7d) later, retinas were isolated and photos were taken with Leica flurorecent scope. Percentages of FG-labeled large-sized, medium-sized and small-sized RGCs per total population were calculated in different parts of retinas.Results. 1) morphological changes of RGCs : ?Increase, decrease and obvious damage in dendritic fields were all observed in early diabetic rat RGCs and RGCs with partial dendrites shrinkage without obvious soma changes, were also found in this study, significant increases in the mean diameter of dendritic fields of classified RG_As (P<0. 001) and RGcs (P<0. 01) were detected in 3-month diabetic rats . (2) The dendrites positions of OFF-center RGCs shifted towards inner nuclear layer in the 1-month and 3-month diabetes, especially in RG_Bs and RGcs (P<0.001). (3) Strange RGCs appeared in the 1-month and 3-month diabetes. 2) the retrograde axonal transport abilities of different kind of RGCs: the mean percentage of small-sized RGCs was smaller than control at 12h after FG injection (P<0. 001), but same at 7d after FG injection (P>0. 05). The mean percentage of large-sized RGCs decreased at 7d after FG injection (P<0. 01).Conclusion. 1) In short-term diabetes, dying and surviving RGCs with compensatory coexisted in the same retina. Dendrites degeneration and compensatory...