Objective To investigate the protective effect of recombinant erythropoietin (EPO) on the photoreceptor cells in rat with retinal detachment (RD).Methods One hundred and sixtytwo normal male rats were randomly divided into normal control (NC) group, RD model group, RD+phosphate buffer solution （RD+PBS） group, RD+EPO 100 ng group, RD+EPO 200 ng group and RD+EPO 400 ng group. Three days after RD, activated caspase3 and bclXL were detected by Western blot and/or immunofluorescence, and apoptosis were measured by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate digoxigenin nick-end labeling（TUNEL）. Fourteen and 28 days and two months after RD, the outer nuclear layer （ONL）thickness was measured by histopathologic method.Results Western bolt indicated that the protein level of activated caspase-3 and bcl-XL between six groups were statistically significant（F=35.96, 30.75；P＜0.01）. The number of TUNEL positive cells and activated caspase-3 positive cells are consistent with each other in different groups. Fourteen days and two months after RD，the differences of ONL thickness between six groups were statistically significant（F=21.52，96.25；P＜0.01）.Conclusion Supplement of EPO after RD can alleviate apoptosis by inhibiting of the caspase-3 activity and increasing the expression of bcl-XL,thus exerts protective effect on photoreceptor cells.
ObjectiveTo investigate the expression of interleukin-18（IL-18）and signal transducers and activators of transcription 5（STAT5）in retina of 4-24-week-old diabetic rats, and explore the potential molecular mechanisms involved in diabetic retinopathy (DR).MethodsRetinal gene expression profile of healthy and 8-week-old diabetic rats was established with restriction fragment differential displaypolymerase chained reaction (RFDD-PCR), and the differences was analyzed by bioinformatics. IL-18 and STAT5 were filtrated as the candidate genes of DR. The expression of IL-18 and STAT5 in retina of diabetic rats with the age of 4, 8, and 24 weeks was observed by semi-quantitative reverse transcriptase-polymerase chain reaction（RT-PCR）.ResultsThe result of RFDD-PCR showed:expression of IL-18 was higher in healthy retina than that in diabetic one; expression of STAT5 was not found in healthy rats but in diabetic ones. The result of RT-PCR showed：compared with the normal, high expression of IL-18 was found in 4-week diabetic retina, reduced in 8-week one, and decreased to the lowest in 24-week one. The expression of STAT5 was not observed in healthy or 4week diabetic retina, but occurred in 8-week one, and increased in 24-week one. ConclusionThe expression of IL-18 and the activation of STAT5 may relate to the occurrance of DR. The expression of IL-18 doesn′t depend on the activation of STAT5. (Chin J Ocul Fundus Dis, 2005,21:258-260)
ObjectiveTo evaluate Micron Ⅳ retinal imaging system in three mouse models of retinal diseases. MethodsMouse models of oxygen induced retinopathy (OIR) model (OIR group), N-methyl-N nitrosourea (MNU) model (MNU group) and N-methyl-D-aspartate (NMDA) model (NMDA group) were induced in 24 healthy male C57BL/6J mice. Fundus photograph, fundus fluorescein angiography (FFA) and optical coherence tomography (OCT) and electroretinogram (ERG) were used to evaluate these mice. All the imaging examinations were performed by Micron Ⅳ retinal imaging system. ResultsOIR mice showed tortuous and dilated retinal vessels in fundus photograph, neovascularization plexus and vascular leakage in FFA, and epiretinal fibrovascular tissue and tortuous expansion vascular vessels in OCT. MNU mice showed wax yellow optic disk without retinal pigmentary changes, slight thinning of retinal blood vessels in FFA, and normal structure and thickness in OCT. The a-wave amplitudes of the maximum mixed response decreased significantly, and were (15.38±4.36) μV and (13.78±5.52) μV at 2 or 3 days of modeling, respectively. NMDA mice showed a pale retina with vasospasm. ERG revealed that there was no obvious change in latency of a- and b-wave, but significantly decreased amplitude of b-wave at 12 hours and 24 hours after modeling with (72.28±7.18) μV and (65.35±9.18) μV, respectively. ConclusionMicron Ⅳ retinal imaging system is a real-time, non-invasive tool to study the retinal structure and function in animal models of retinal diseases.
Retinal ischemia is the common pathologic process in many ophthalmic diseases, including ischemic optic neuropathy, retinal artery and vein occlusion, carotid artery obstructive disease, retinopathy of prematurity, chronic diabetic retinopathy and glaucoma. It is very important to establish animal models to investigate pathology mechanism and explore the treatment of retinal ischemia disease. At present, the commonly used methods for establishing retinal ischemia animal models include increasing intraocular pressure, ligating of blood vessels, suture method, photochemical method, and drug injection etc. This article summarizes the methods to establish the animal models and analyzes the indication for each animal model. It is expected that the method of establishing a retinal ischemic animal model will be helpful to the experimental design of follow-up retinal ischemia studies.