Microparticles are small vesicles that are released by budding of the plasma membrane during cellular activation and apoptotic cell breakdown. A spectrum of cell types can release microparticles including endothelial cells, platelets, macrophages, lymphocytes and tumor cells. Biological effects of microparticles mainly include procoagulant activity, inhibition of inflammation and cancer progression. The present study shows that vitreous microparticles isolated from proliferative diabetic retinopathy (PDR) stimulated endothelial cell proliferation and increased new vessel formation, promoting the pathological neovascularization in PDR patients. Oxidative stress induces the formation of retina pigment epithelium-derived microparticles carrying membrane complement regulatory proteins, which is associated with drusen formation and age related macular degeneration. Microparticles from lymphocyte (LMP) play an important role in anti-angiogenesis by altering the gene expression pattern of angiogenesis-related factors in macrophages. Besides, LMP are important proapoptotic regulators for retinoblastoma cells through reduction of spleen tyrosine kinase expression and upregulation of the p53-p21 pathway which ultimately activates caspase-3. However, how to apply the microparticles in the prevention and treatment of retinal diseases is a major challenge, because the study of the microparticles in the fundus diseases is still limited. Further studies conducted would certainly enhance the application of microparticles in the fundus diseases.
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)
The prevalence of diabetes mellitus in adults of China has reached 12.8%. Diabetic retinopathy (DR) accounts for approximately 1/4-1/3 of the diabetic population. Several millions of people are estimated suffering the advanced stage of DR, including severe non-proliferative DR (NPDR), proliferative DR (PDR) and diabetic macular edema (DME), which seriously threat to the patients’ vision. On the basis of systematic prevention and control of diabetes and its complications, prevention of the moderate and high-risk NPDR from progressing to the advanced stage is the final efforts to avoid diabetic blindness. The implementation of the DR severity scale is helpful to assess the severity, risk factors for its progression, treatment efficacy and prognosis. In the eyes with vision-threatening DR, early application of biotherapy of anti-vascular endothelial growth factor can improve DR with regression of retinal neovascularization, but whether it is possible to induce capillary re-canalization in the non-perfusion area needs more investigation. Laser photocoagulation remains the mainstay treatment for non-center-involved DME and PDR.
Objective To explore the effect of oxygen inhalation on the retinae of newborn rats and its mechanism.Methods We mimicked the retinopathy of prematurity(ROP) by putting the newborn rats in high concentrated oxygen. One-day old rats were put into the oxygen box with the oxygen concentration of 80% for continuous 7 days; then in air condition for 7 days. The arterial blood oxygen pressure, retinal superoxide dismutase (SOD), and malondialdehyde (MDA) of the rats (1,2,4,7,8,9,11,14 days old) were examined. The diameter of retinal vessels′main branch and the coverage rate of peripheral vessels were measured in 7- and 14-day-old rats by ink perfusion. The retinal neovascularization of rats (8,9,11, 14 days old) were observed by HE staining. The rats of the same age fed in air condition were in the control group.Results The differential pressures of blood oxygen of rats (1,2,4,7 days old) in study group were significantly higher than those in the control group (P＜0.01), while the differential pressures of blood oxygen of rats (8,9,11,14 days old) in study group were lower than those in the control group (P＞0.05). The contents of SOD of the retinae in the rats ( 1,2,4,7,8 days old) were significantly lower than those in the control group(P＜0.01, P＜0.05 ), while the contents of MDA were significantly higher than those in the control group (P＜0.01,P＜0.05). The diameter of retinal vessels′main branch in 7-day rats was 75% of the control group, and the coverage rate of peripheral vessels was 22% of the control group; and was 61% and 73% respectively in 14-day-old rats. The neovascularization could be seen in 16.7% of the rats in the study group and nought in the control group.Conclusion The damage of free radical of the retina in high concentrated oxygen and hypoxia situation after oxygen supply may be one of the most important mechanism of ROP. (Chin J Ocul Fundus Dis，2003，19：269-332)
Purpose To clarify the relationship between diabetic retinopathy (DR) and maculopathy (DM) and explore the clinical implication of independent graduation of DM. Methods Fundus fluorescein angiography and routine ophthalmological examination were performed on 582 cases of diabetes.Their ocular fundi and macular impairments were graded. Results In general,the severity of diabetic macular impairment was accompanied by retinal involvement,but discrepancy existed between DM and DR.Degree I DM occurred in 5.4% (16/294) among cases without DR,in stage IV DR,degree Ⅲ DM accounted for the most part ,54.5% (116/213).There were still 5.1% (2/39) cases without DM in stage Ⅴ DR. Conclusion The degree of the macular lesions in DM is often not in parallel with the gradation of general affections in retinal tissue other than in macular region in DR,therefore,independentg radation of diabetic maculopathy has its clinical significance for choosing the optimal period of treating maculopathy and preserving the macular function. (Chin J Ocul Fundus Dis,2000,16:153-154)
ObjectiveTo investigate the expression and relation of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in rats with diabetic retinopathy.MethodFifty-five Wistar rats were randomly divided into the control group (10 rats), and 1, 3, and 5-month-diabetes group (15 rats in each diabetes group), and the diabetic models were set up. The expressions of VEGF and bFGF were detected by situ hybridation and immunohistochemistry on retinal paraffin sections.ResultsThe results of situ hybridation showed that expression of bFGF was found in 3-month-deatbtes group with the percentage of 77.8%, and 88.9% in 5-month-deatbtes group; the positive expression of VEGF was not found in 3-month-deatbtes group but in 5-month-deatbtes group with the percentage of 66.7%. Immunohistochemistry indicated that the positive expression of bFGF started in 3-month-deatbtes group with the percentage of 55.6%, and 88.9% in 5-month-deatbtes group; the percentage of the expression of VEGF was 33.3% in 3-month-deatbtes group and 88.9% in 5-month-deatbtes group.ConclusionThe expression of VEGF occurs after the expression of bFGF in rats with DR.(Chin J Ocul Fundus Dis, 2005,21:37-40)
ObjectiveTo analysis the fundus characteristics of fundus fluorescein angiography (FFA) of retinopathy of prematurity (ROP). MethodsEighty-four cases (168 eyes) who were diagnosed with ROP by a binocular indirect ophthalmoscope were included in the study. Among the 84 cases, there were 2 cases (4 eyes) of stage 1 ROP, 26 cases (52 eyes) of stage 2 ROP, 40 cases (80 eyes) of stage 3 ROP, 4 cases (8 eyes) of stage 4 ROP, and 4 cases (8 eyes) of stage 5 ROP, 9 cases (18 eyes) of plus disease, 8 cases (16 eyes) of aggressive posterior ROP (APROP). All infants received FFA with RetCam Ⅱ under general anesthesia and mydriasis. The retinal vein morphology, capillary filling state, neovascularization morphology and fluorescein leakage were observed. ResultsFFA revealed increased branching, expansion and tortuous peripheral retinal capillaries, increased capillary permeability with a small amount of fluorescein leakage in stage 1 ROP. There was a clear dividing line between the vascular area and the remote avascular area. In stage 2, the peripheral branches of temporal retinal blood vessels increased, and parallel distributed like a broom. The capillary end anastomosed with each other to form a loop. The fibrous tissues at the lesion edge proliferated as a ridge, with popcorn phenomenon. In stage 3, the ridge continued broadening, and the neovascular fibrous membrane formed breakthrough internal limiting membrane, stretched into the vitreous with a lot of fluorescein leakage. The ridge and remote avascular zone demarcated clearly. In stage 4 and 5, the vessel changes had similar phenomenon with the stage 2 and 3 in undetached retina, but the vessels in the detached retina expanded with fluorescein leakage. As for plus disease, the retinal arterioles in the posterior pole were tortuous, there were a large number of non-perfusion area in the peripheral retina with hemorrhage and obscured fluorescence. The retinal vessels in posterior pole in AP-ROP were also tortuous, and the capillaries were extreme expanded, while there were very few tortuous vessels and no capillary formation in the other part of retina.At the avascular zone boundaries, there were a large group of neovascularization with fluorescein leakage. ConclusionsThe demarcation line separating the avascular from the vascularized retinal regions is formed in stage 1, 2 and 3, and the amount of fluorescein leakage gradually increase from stage 1 to stage 3 ROP. The detached retina of stage 4 and stage 5 has an unclear focal length in the FFA. The plus disease mainly has arteriolar tortuosity in the posterior pole retina. In the AP-ROP cases, both of the arterioles and venules in posterior pole of retina are tortuous and expanding with neovascularization leakage of fluorescein.
Objective To observe the oxidative damage of mtDNA, apoptosis and expression of adhesion molecules in retinal capillary cells of diabetic rat with different disease courses. Methods One hundred Sprague-Dawley rats were randomly divided into the control group and the experimental group. The rats of experimental group were induced with streptozotocin (STZ) injection creating a diabetic model. Then they were divided into DR1m, DR2m DR3m group according to disease courses. The rats of control group were divided into NR1m, NR2m, NR3m group. Rat retinal capillaries were prepared, and then the contents of undamaged mtDNA were examined by Southern blot combined with Fpg. The expression of cyclooxygenase (COX)-1 encoded by mtDNA and transcription factors A (mtTFA) mRNA were detected by real-time quantitative polymerase chain reaction (RT-PCR). Apoptosis and expression of intercellular adhesion molecule-1 (ICAM-1) were detected by terminal dUT nick endlabeling (TUNEL) immuno-fluorescence and immunohistochemistry respectively. Results The contents of undamaged mtDNA in rats of DR1m, DR2m, DR3m were less than those of NR1m、NR2m、NR3m. The contents of undamaged mtDNA in diabetic rats decreased with the increase of disease courses. In addition, the mRNA levels of COX-1 and mtTFA were downregulated in diabetic rats. The positive cells of TUNEL and ICAM-1TUNEL and ICAM-1 in diabetic rats increased with the increase of disease courses. Conclusion With the increase of disease courses, mtDNA damage and apoptotic cells are increased, while the expression of mRNA encoded by mtDNA and ICAM-1 decreased in retinal capillary cells in diabetic rats.