Objective To investigate the alteration of protein kinase C (PKC) and endothelin system in early diabetic rats, and the effect of specific PKC inhibitor on the expression of retinal endothelin-1 (ET-1). Methods The rats model with streptozotocin(STZ)-induced diabetes were set up. The expression of retinal PKC was detected by enzyme-linked immunoabsorbent assay (ELISA). The expression of retinal ET-1, ET-3, ET-A and ET-B receptor mRNA was determined by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The alteration of retinal ET-1 mRNA after intravitreal injection of PKC inhibitor GF109203X in diabetic rats was also observed. Results The activities of membranous PKC were significantly increased in 2-week diabetic rats compared with that in normal rats（t=3.296 , P=0.008）, while activities of cytosolic PKC were unchangeable（t=0.138, P=0.894）. The expression of retinal ET-1 mRNA was significantly increased（P=0.008）, while no change was found in expression of ET-3, ET-A and ET-B mRNA（P=0.918，P=0.889，P=0.500）. After intravitreal in jection of 10-5、10-6、10-7 mol/L PKC inhibitor GF109203X in diabetic rats, the expression of retinal ET-1 mRNA was decreased in a dose-dependent manner compared with the control rats. Conclusion Activation of PKC and increased expression of ET-1 could be found in the retina of early diabetic rats, and PKC inhibitor could inhibit the expression of retinal ET-1. (Chin J Ocul Fundus Dis，2004，20：168-171)
Objectives To investigate the expression of pax-6 in ret ina of in fant monkeys with myopia induced by optical defocus, and to determine the role of pax-6 would play or not in onset and development of myopia and emmetropization.Methods Nine healthy infant rhesus monkeys, aged from 1 to 3 months, were selected and wore spectacle lenses or underwent photorefractive keratectomy (PRK).Transcription polymerase chain reaction method and quantitative analysis were used to determine the expression of pax-6 in the retina with myopia induced by optical defocus in different time, and the result was compared with that in retina without myopia.Results The myopia caused by hyperopic defocus was found. The expression of pax-6 in the retina with myopia induced by optical defocus was significantly higher than that in the retina without myopia（t=3.480，P=0.004）.Conclusions The expression of pax-6 is enhanced by hyperopic defocus in the infant monkey retina, which suggests that pax-6 may be involved in vision-dependent eye growth and emmetropization. (Chin J Ocul Fundus Dis，2003，19：201-268)
Objective To set up a new animal model of branch retinal vein occlusion (BRVO), which was quite similar to the clinical features and pathogenesis of this disease. Methods The animal model was set up by laser (krypton green 90 ～150 mW) irradiating a branch of central retinal vein after intravenous injection of photochemical drug (3% rose bengal) to 5 pigmented rabbits, and the model was confirmed by fundus fluorescein angiography (FFA) and pathological examination. Results The model of BRVO was successfully set up, which was confirmed by clinical examination and FFA. Pathological examination showed that the occlusion was caused by intra-venousthrombosis. Conclusion An experimental BRVO model, which has the similar pathological processes of occlusion of central retinal vein and intra-venous thrombosis as those in clinic can be set up by using photochemical method. The method is quite simple, and it offers a better animal model for clinical therapeutic research. (Chin J Ocul Fundus Dis,2002,18:23-25)