The Effects Of Glucocorticoids On Retina In Diabetic Rats

Objective To investigate the effects of glucocorticoids on retinal nerve tissue in diabetic rats.Methods The diabetic model was established by a single injection of streptozotocin. Diabetic rats were intravitrealy injected with adenovirus vehicle(DM group), carried glucocorticoids receptor antisense(si GR group), or scrambled nucleotide(sc RNA group). Control group(CON group) were na?ve rats intravitreal injected with adenovirus vehicle. Twelve weeks later, the density of retinal ganglion cell(RGC) and thickness of retina were detected by HE staining, and the expression of ROCK was observed by Immunohistochemical staining and Western blot.Results HE staining showed that, the retinal RGC cells were arranged regularly, uniform density in CON group and si GR group, while the number of retinal RGC cells decreased, uneven density in DM group and sc RNA group. CON group, DM group, sc RNA group and si GR group of retinal RGC density were(1209±295),(843±236),(861±263),(1139±304) /mm2 respectively.Compared with CON group, retinal RGC cells density decreased significantly in DM group and sc RNA group(P<0.01),and the density of RGC in si GR group had no significant differences(P>0.05). The results of immunohistochemistry detection showed that, compared with CON group,there were found plenty ofROCK positive neurons in DM group and sc RNA group of stratum ganglionare retinae and inner nuclear layer, they were more and hyperchromatic,while there did not change significantly coloring in si GR group and CON group. Western-blots were used for ROCK expression assays in the retina of rats,relative quantitative expression of ROCK in CON group, DM group, sc RNA group and si GR group were(20.1±4.6)%,(28.6±3.3)% 、(29.1±4.7)%,(19.6±3.4)% respectively. Compared with CON group, DM group and sc RNA group increased expression of retinal ROCK(P<0.01), si GR group had no significant differences(P>0.05).The measurement results of rat retinal inner layer thickness showed that, compared with CON group, retinal thickness were significantly thinner in four quadrants of retinal nasal sidel and temporal sides of DM group and sc RNA group(P<0.01), while si GR group had no significant differences(P>0.05).Conclusions Inhibition of glucocorticoids in diabetes reverses the expression of retinal ROCK, RGC density, and retinal thickness.