Changes Of Retinal Morphology And Expression Of Brn-3a In Chronic High Intraocular Pressure Rats

ObjectiveThe purpose of this paper was to investigate the changes of intraocular pressure(IOP) and morphology of retina and the expression of Brn-3a in chronic ocular hypertension rats.MethodsExperimental glaucoma was induced unilaterally in left eyes of 30 health adult SD rats by cauterizing sup-scleral veins, and the right eyes were as control.IOP was measured using the Tono-Pen before and 30 minutes,1 day,3,7,14,28 day after surgery. Rat models were sacrificed in 1day,3,5,7,14,28 day after operation. Morphology of retinal every layer was investigated and retinal ganglian cells (RGCs) were counted by hematoxylin- eosine and Toluidine blue staining of retinal paraffin section respectively. Expression of Brn-3a was measured by immunohistochemical method.ResultsIOP of basal line was 13.61±1.60 mmHg with the top IOP 34.46±4.65 mmHg and the 28day IOP 21.60±0.89 mmHg.IOP of the experimental eyes was higher than that of the control eyes. In the normal group,there were ganglion cell layer(GCL),inner nuclear layer(INL) and outer nuclear layer(ONL) in retina of rat. GCL was monolayer,alignment rarefaction. In the experimental group,fiber layer showed dropsy ,Vacuole , the size of cell bady was not uniform. Chromatospherite was not clear or lost.The counting of RGCs in the normal contral eyes was 29.08±1.98(n=5, cells×400),reducing 3.17%,7.84%,14.60%,22.40% at 1 day, 7, 14, 28 day respectively.Comparing to the normal contral group,a significant difference was seen among model group except the 1day group(p<0.05).The portain of Brn-3a only resided in the GCL of retina.The expression of Brn-3a with a considerable difference among the glaucoma eyes and the normal control eyes(p<0.01).Conclusion Establishment of chronic glaucoma model using Shareef-Sharma model successfully, the IOP presents moderate increase in an injury eye by cauterizing sup-scleral veins. Conspicuous dependablity is existence between the apoptosis of RGCs and the duration of intraocular hypertension. The counting of RGCs and the expression of Brn-3a appear to be a descending tendency. This approach is facilitated by the fact that the Brn-3a signal is nuclear.