The pathogenesis of diabetic retinopathy is complicated. The vast network of multiple factors including unifying mechanism, inflammatory reaction, neuron degeneration and metabolic memory of glucose, and the four established pathogenic molecular pathways are hotspots of mechanism research for diabetic retinopathy. Nevertheless, these researches may be only one corner of the ldquo;icebergrdquo; of DR mechanism, and we still face enormous challenges in DR mechanism research. Collaboration with multiple disciplines to study the relationship between DR and diabetes and other systemic diseases, search novel therapy targets may increase the result in an unexpected windfall for DR basic research.
Objective To investigate Kir4.1 expressions in Muuml;ller cells under high glucose conditions and treatment of pigment epitheliumderived factor (PEDF）. Methods Cultured rat Muuml;ller cells were divided into control group (5 mmol/L glucose), high glucose group (25 mmol/L glucose), PEDF treatment group (25 mmol/L glucose+100 ng/ml PEDF) and intervention control group（25 mmol/L glucose+phosphate buffer solution）. Kir4.1 expressions were measured by Western blot and real-time reverse transcription polymerase chain reaction (RT-PCR). Reactive oxygen species (ROS) productions were measured using 2prime;7prime;dichlorofluorescin diacetate and glutathione peroxidase （GPx）expressions were studied by real-time RT-PCR. Results By Western blot and real-time RT-PCR, it was found the expressions of Kir4.1 decreased obviously under high glucose conditions (real-time RT-PCR: t=4.12, P＜0.05; Western blot: t=3.53,P＜0.05); simultaneously, ROS generation was increased （t=3.76,P＜0.05）and GPx level was decreased （t=3.18,P＜0.05）. PEDF treatment inhibited the high glucose-induced Kir4.1 down regulation (real-time RT-PCR: t=3.66, P＜0.05; Western blot: t=6.43,P＜0.01) and decreased ROS generations （t=4.11,P＜0.05） and increased GPx levels (t=5.12,P＜0.01）. Conclusions The high glucose can supress Kir4.1 expressions in Muuml;ller cells by oxidative stress, and PEDF can ameliorate these effects.
Objective To observe the influence of interleukin-1beta; (IL-1beta;) on the expression of phosphorylated signal transducers and activators of transcription 3 (pSTAT 3) in rat retinal Muuml;ller cells.Methods For in vitro study cultured Muuml;ller cells were treated with IL-1beta; of different concentrations (0, 0.1, 1, 5 and 10 ng/ml) for 24 hours. For in vivo study, 32 Sprague-Dawley（SD）rats were divided into 4 groups randomly (control group，100，500 and 1000 ng/ml group) with 8 rats in each group. After 24 hours of injection with phosphate buffered solution (PBS), or 100,500,1000 ng/ml IL-1beta; into the vitreous cavities of the above rats, retinas were harvested. The expressions of pSTAT3 in cultured Muuml;ller cells or treated retinas were evaluated by indirect immunofluorescence and western blotting.Results After 24 hours of incubation without IL-1beta;, pSTAT3 has little expression in cultured Muuml;ller cells, but was upregulated by 1 ng/ml or higher IL-1beta; in a dosagedependent manner (F=46.64, 43.78;P＜0.01). pSTAT3 was not expressed in adult rat retina, but was upregulated by vitreous injection of 100 ng/ml or higher IL-1beta; in a dosagedependent manner (F=73.53,43.70;P＜0.01).pSTAT3 expressed mainly in inner nuclear layer and ganglion cell layer. Doublelabeling showed that there was no costaining of pSTAT3 and glial fibrillary acidic protein (GFAP) in retina of control group, but there were many costained Muuml;ller cells in retinas treated with IL-1beta;.Conclusions Expression of pSTAT3 in Muuml;ller cells could be activated by IL-1beta; which may represent one pathway link to reactive gliosis.
Objective To observe the changes of expression of glutamine synthetase (GS) in early diabetic ratsprime; retina and investigate its possible mechanism. Methods Three groups of streptozotocininduced diabetic models of SpragueDawley (SD) rats with different diseased courses, ie, 1 month, 2 months, and 3 months, respectively, with 8 rats in each group, and 8 normal ones as control were examined. The expressions of GS, interleukin-1beta; (IL-1beta;) and c-Jun in retina in the 4 groups were detected by indirect immunofluorescence and western blotting techniques. Meanwhile, different doses of IL-1beta;（0,100,500,and 1000 ng/ml） were injected into the vitreous cavities of 32 normal rats (8 rats in each group), and 24 hours later, the expressions of GS and c-Jun in retina were detected by the same methods. Results The expression of GS in retina did not changed in control group or in 1 month and 2 months group, but decreased obviously in 3 months group comparing with which in the control group (Plt;0.01).The expressions of c-Jun and IL-1beta; in retina in control group were very low, but increased gradually in diabetic rats in 1-3 months group, which significantly differed from which in the control group (Plt;0.01). Vitreous injection with IL-1beta; (500 and 1000 ng/ml) down regulated the expressions of GS, and the expression of c-Jun increased in a dose-dependent way after injection with IL-1beta; at the concentration of 100 ng/ml. Conclusions In early diabetic ratsrsquo; retina, IL-1beta; may down regulate the expression of GS. The possible mechanism may be the activation of c-Jun by IL-1beta;. (Chin J Ocul Fundus Dis,2007,23:260-264)
ObjectiveTo observe and analyze the clinical features and prognosis of endogenous klebsiella pneumoniae endophthalmitis (EKPE).MethodsThis is a retrospective case series study. Seven patients (8 eyes) with EKPE were enrolled in this study. There were 3 males (4 eyes) and 4 females (4 eyes). The ages were from 39 to 76 years, the mean age was 57.29 years. All these cases had no history of trauma and surgery. Meanwhile, they all had some risk factors, such as infection, diabetes mellitus, systemic lupus erythematosus, liver abscess, renal insufficiency undergoing dialysis treatment, Hodgkin lymphoma and so on. All the eyes were undertaken visual acuity, slit lamp and fundus examination to observe the eye conditions. Seven eyes were undertaken pars plana vitrectomy with intravitreal injection of antibiotics from 2 days to 2 weeks after onset. And only one eye was undertaken intravitreal injection of antibiotics without surgery. Microbial stains and culture were performed for 7 eyes using vitreous and aqueous fluid samples from the procedures of vitrectomy. Meanwhile, culture and drug sensitive tests were performed from blood samples. According to the result of the drug sensitive tests, carbapenems such as imipenem and meropenem were used in each patient through intravenous injection from 1 to 2 weeks. During the follow up period from 3 days to 1 year, prognosis was observed at each office visit.ResultsFrom these eight eyes, presenting visual acuity was light perception (4 eyes), hand motion (3 eyes), 0.1 (1 eye). Hypopyon (6 eyes), aqueous fluid opacity (2 eyes) and diffuse vitreous opacity (8 eyes) were found. Changes in fundus like optic disc, macular edema and retinal vascular occlusion could be observed. Cultures of the vitreous and aqueous fluid samples from vitrectomy were all point out to klebsiella pneumoniae. At last office visit, the visual acuity of patients with hypopyon was no light perception (1 eye), light perception (1 eye), hand motion (1 eye). The visual acuity of patients without hypopyon was 0.05 (1 eye) and 0.5(1 eye). Finally, 1 eye was underwent enucleation and one patient with binocular disease was died of multiple organ failure.ConclusionsEKPE is almost unilateral attacked. Changes in fundus like optic disc, macular edema and retinal vascular occlusion can be observed. EKPE is commonly associated with poor visual outcomes. It is useful to save patients’ visual acuity by performing vitrectomy before hypopyon happened.
Alzheimer's disease is a common neuro-degenerative disease. The clinical diagnosis mainly depends on the patient's complaint, the score of mini-mental state examination and Montreal cognitive assessment scale, and the comprehensive judgment of MRI and other imaging examinations. Retina is homologous to brain tissue, and their vascular systems have similar physiological characteristics to small blood vessels in the brain. Numerous studies found that the thickness of retinal nerve fiber layer, visual function, retinal blood vessels and retinal oxygen saturation were changed in AD patients to different degrees. To explore the formation mechanism and significance of ocular fundus changes in AD patients will be helpful to select specific, sensitive and simple methods for early observation and evaluation of AD.
Ischemic retinopathy, resulting in multiple lesions like microvasculature damage, inflammation and neovascularization, is a major contributor of vision damage. In these pathological changes, retinal glia cannot be ignored in the development of retinopathy. They constitute a highly versatile population that interacts with various cells to maintain homeostasis and limit disease. Therefore, glial activation and gliosis are strikingly ubiquitous responses to almost every form of retinal disease. Both of microglial cells and Müller cells are major intrinsic retinal glial cells and they are in close relationship, which means they can influence each other, make joint action or even become interdependent. They exhibit morphological and functional changes to have an impact on degree of retinal injury through different responses, which mediated by glial cells are important not only for course of disease progression, but also for the maintenance of neuronal and photoreceptor survival. Thus, defining the mechanisms that underlie communications between microglial cells and Müller cells could enable the development of more selective therapeutic targets, with great potential clinical applications.
Objective To compare the outcomes of 23G and 20G vitrectomy in treatment of proliferative diabetic retinopathy (PDR). Methods This was a prospective randomized study. One hundred twenty six patients (142 eyes) suffering from PDR with symptoms requiring vitrectomy were randomly divided into 20G vitrectomy group (66 patients, 74 eyes) and 23G vitrectomy group (60patients,68eyes). Visual acuity, intraocular pressures,indirect ophthalmoscopy, B-scan ultrasound, tear film break up time (BUT), Schirmer Ⅰ test (S Ⅰ T), astigmatic power and the astigmatic axial at 6 mm area of anterior and posterior corneal surface were observed and measured before surgery. The follow-up period was 15.0 and 12.5 months separately in 20G and 23G groups. Intraoperative complications, operation time, postoperative visual acuity, intraocular pressure, postoperative complications, reoperation, and postoperative ocular conditions including changes of astigmatic power and the astigmatic axial measurements were analyzed. Results At last follow-up, there was 49 eyes (66.2%) and 47 eyes (69.1%) with visual acuity ge;0.05 in 20G and 23G groups. Comparing visual acuity ge;0.05, there was no statistical difference between the groups (chi;2=0.14, P＞0.05). The eyes suffering from iatrogenic injuries were 18 (24.3%) and seven (10.3%). There was obvious difference in iatrogenic injury between the two groups (chi;2=4.81, P＜0.05). The mean surgical times were (69.0plusmn;8.2) and (51.0plusmn;6.3) minutes in 20G and 23G group, which was significantly different (t=3.65, P＜0.05). The postoperative third day, hypotony was detected in three (4.1%) and 11 eyes (14.7%) in 20G and 23G group, which was a significantly different (chi;2=5.85, P＜0.05). Postoperatively high intraocular pressures were not significantly different between the two groups (chi;2=2.54,P＞0.05). There were 24 (32.4%) and 14 eyes (20.6%) in 20G and 23G group. There were significant differences in BUT, SⅠT, astigmatic power and the astigmatic axial measurements compared with those preoperatively at the first month after operation (t=3.35, 4.12, -3.12, -3.22; P＜0.05), but no significant differences in them at the third and sixth month after operation (third month: t=0.45, 0.98, -2.12, -1.02; P＞0.05, and the sixth month: t=0.95, 1.48, -1.02, -2.11; P＞0.05). In 23G group, there were no significant differences in BUT, SⅠT, astigmatic power and the astigmatic axial measurements compared with those preoperatively at the first, third and sixth month after operation (first month: t=1.21, 1.46, -2.32, -1.61; P＞0.05, third month: t=1.45, 2.21, -2.19, -1.89; P＞0.05, and sixth month: t=1.92, 1.25, -1.76, -2.35; P＞0.05). Conclusion 23G vitrectomy is a safe and effective treatment for PDR with shorter surgery time, fewer surgical complications and postoperative ocular surface changes.
Objective To observe the effect of pigment epithelium-derived factor (PEDF）on glutamate metabolism in diabetic rat retina. Methods 78 Sprague-Dawley rats were randomly divided into the model group, model control group, PEDF intervention group and intervention control group. There were some dead and euglycemia rats at the end of experiment, so only 12 rats in each group were included in the statistical analysis. The diabetic retinopathy rat model of the model, PEDF intervention and intervention control group were induced with streptozotocin injection. The rats in the model group were not intervened. The monthly-age matched normal rats of model group were in the model control group. The left eyes of rats were received intravitreal injection with 5 mu;l (0.1 mu;g/mu;l) PEDF (PEDF intervention group) or 5 mu;l phosphate buffer solution (intervention control group). The expressions of L-glutamate/L-aspartate transporter in retina were analyzed by western blot and real time RT-PCR techniques and glutamate content in retina was analyzed by high-pressure liquid chromatography (HPLC). Cultured rat Muuml;ller cells were divided into the control,experimental, PEDF intervention and intervention control group, GLAST expressions were detected by fluorescence immunofluorescence and real-time RT-PCR techniques. The glutamate up-take activity of Muuml;ller cells was determined by intracellular [3H] labeled D, L-glutamate concentration with scintillation counting. Results Western blot and real-time RT-PCR showed that GLAST expression decreased (real-time RT-PCR：t=8.86,Plt;0.01；Western blot：t=3.42,P＜0.05), glutamate content increased（t=4.01,P＜0.05）in model group compared with the model control group; GLAST expression increased (real-time RT-PCR：t=3.56,P＜0.05；Western blot：t=3.52,P＜0.05), glutamate content decreased（t=4.36,P＜0.05）in the PEDF intervention group compared with the intervention control group. Real-time RT-PCR and fluorescence immunofluorescence showed that high glucose down-regulate GLAST expressions in Muuml;ller cells (rea-time RT-PCR：t=3.48,P＜0.05；fluorescence immunofluorescence：t=4.72,P＜0.05 ) and impair glutamate uptake activity of Muuml;ller cells (t=3.81, Plt;0.05). Under high glucose conditions, PEDF up-regulated GLAST expression significantly (real-time RT-PCR：t=6.82,P＜0.01；fluorescence immunofluorescence：t=3.72,P＜0.05) and ameliorated the glutamate up-take activity of Muuml;ller cells（t=4.14, Plt;0.05). Conclusions In diabetic rats, PEDF may improve the activity of GLAST in Muuml;ller cells, thus ameliorate retinal glutamate metabolism and inhibit death of retinal ganglion cells.
Objective To investigate the effect of pigment epitheliumderived factor (PEDF）on the expression of glutamine synthetase in retinal Muuml;ller cells of diabetic rats.Methods Diabetic rats were induced with streptozotocin injection.Before and after injection of 10 mu;l (0.1 mu;g/mu;l) PEDF (experimental group) or 10 mu;l PBS (control group) into the vitreous cavities of diabetic rats respectively for 48 hours,the expressions of GS and IL-1beta; in retina were analyzed by immunohistochemistry and real time RTPCR techniques. After being treated with 100 ng/ml PEDF for 24 hours in high glucose conditions,the expressions of GS and IL-1beta; in cultured Muuml;ller cells were studied by western blot and real time RT-PCR techniques. Apoptosis was analyzed by flow cytometry after Annexin V fluorescein isothiocyanate/Propidium idoium (Annexin V-FITC/PI) staining.Results By immunohistochemistry (the protein level) and real time RT-PCR (the mRNA level),it was found that the expression of GS decreased and the expression of IL-1beta; increased obviously (real time RT-PCR：GS:t=4.23,P＜0.01；IL-1beta;:t=16.73,P＜0.01；immunohistochemistry：GS: t=5.13,P＜0.01；IL-1beta;:t=9.32,P＜0.01) in diabetic rats. After injection of 10 mu;l (0.1 mu;g/mu;l) PEDF into the vitreous cavities of diabetic rats for 48 hours,it was found that the expression of GS increased and the expression of IL-1beta; decreased significantly(RT-PCR GS:t=3.87,P＜0.01IL-1beta;:t=3.61,P＜0.05;immunohistochemistry:GS:t=3.32, P＜0.05；IL-1beta;: t=2.63,P＜0.05). Under high glucose conditions, 100 ng/ml PEDF induced decreasing expression of IL-1beta; and increasing expression of GS significantly (RT-PCR：GS: t=2.89, P＜0.05；IL-1beta;: t=3.37,P＜0.05；Western blot：GS:t=2.66,P＜0.05;IL-1beta;:t=3.23,P＜0.05).Apoptosis of Muuml;ller cells under high glucose conditions was inhibited significantly by the treatment with 100 nmol/ml PEDF (t=3.21,P＜0.05). Conclusions In diabetic rats,PEDF may decrease expression of IL-1beta; in rat retinal Muuml;ller cells, which may result in increasing expression of GS.To some degree,it inhibits possibly the death of retinal ganglion cells.