Objective To investigate the effect of methylprednisolone on the expression of glial fibrillary acidic protein (GFAP) and proliferating cell nuclear antigen (PCNA) in Müller cells of rats’ retinae injured by laser. Methods Forty SD rats were randomly divided into two groups and inflicted with laser photocoagulation.The rats in treatment group were given methylprednisolone by intraperitoneal injection with a dose of 30 mg/kg for 3 days.At the 3rd,7th,14th,and 28th day after photocoagulation respectively, the eyes were enucleated,fixed and cut into sections.Immunohistochemical examination was used to detect the expression of PCNA and GFAP. Results After photocoagulation the Müller cells expressed PCNA both in the treatment and control group,and the expression of PCNA decreased sharply after 3 days. The expression of PCNA in treatment group was less than that in control group. After photocoagulation the Müller cells also expressed GFAP and the expression of GFAP lasted for at least 28 days ,and the expression of GFAP expression in the treatment group was less than that in the control group. Conclusion Methylprednisolone can reduce the expression of GFAP and PCNA in Müller cells of rats’ retinae injured by laser. (Chin J Ocul Fundus Dis, 2002, 18: 299-301)
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 develop a method for the primary culture of retinal Muuml;ller cells of adult rabbit in vitro. Methods Retina was isolated from adult rabbit, cut into 1 mm times; 1 mm pieces, and placed into Dulbecco modified Eagle medium/F12 containing 20% fetal bovine serum to culture. Cultured cells were identified by inverted phase contrast microscope, transmissim electron microscope and immunohistochemistry staining method. Results Visible cell processes grew out from the retinal tissues after three days culture, and more cells grew radically around the retina after seven days culture. The cultured cells were often inflated at one side and had one long process at another side, and the nuclei were elliptical and there were two or more than two nucleoli under inverted phase contrast microscope. The cytoplasm was rich and contained abundant microfilaments in eight to ten nanometers under transmission electron microscope. Immunohistochemistry assay showed that 95% of the cells were positive for glial fibrillary acidic protein and cellular retinaldehydebinding protein. Conclusion Rabbit retinal Muuml;ller cells can be cultured by the explant culture method.
Müller cells are glial cells of the retina, whose major processes cross the internal and external limiting membranes of the retina, maintaining the function and metabolism of retinal photoreceptors and neurons. Their structure and function are closely related to the development of macular hole (MH). Müller cells are involved in the formation and recovery of MH from the aspect of traction and protein, and their morphology and biological function also influence the regression of MH. The current treatment modality for MH is vitrectomy combined with internal limiting membrane (ILM) peeling, in which Müller cells play a dual role after ILM peeling in different stages of MH. And its potential to re-acquire a progenitor-like state following retinal injury with the ability to proliferate and generate new neurons making it a current research hot topic, which can be a reference and inspiration for clinical treatment.
ObjectiveTo observe the effect of tert-Butylhydroquinone (tBHQ) on the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase (HO)-1 and phosphatidylinositol 3-kinase (PI3K) in high glucose cultured retinal Müller cells; and to investigate the anti-oxidative stress and anti-apoptotic effects of tBHQ.MethodsRetinal Müller cells were divided into normal glucose group (5.5 mmol/L, N group), high glucose group (45 mmol/L, HG group) and tBHQ intervention group (HG+tBHQ group). After retinal Müller cells were cultured with high glucose for 48 hours, the pretreatment with tBHQ (20 μmol/L) induced the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and HO-1. The Müller cells were identified by immunofluorescence staining. The expressions of Nrf2, HO-1, PI3K, B-cell lymphoma-2 (Bcl-2) and Bax were detected by Western blot and real-time fluorescence quantitative PCR. Flow cytometry was used to detect the apoptosis of retinal Müller cells in rats.ResultsMüller cytoplasm and nucleus GS showed strong positive, large cell body, abundant cytoplasm, uniform green fluorescence; nuclear DAPI staining round or oval, clear boundary. The expression of Nrf2 protein (t=4.114, P=0.006), HO-1 protein (t=9.275, P=0.000), Nrf2 mRNA (t=7.292, P=0.000) and HO-1 mRNA (t=15.014, P=0.000) in the HG group were higher than those in the N group. The expressions of Nrf2 protein (t=7.847, P=0.000) ,HO-1 protein (t=7.947, P=0.000), PI3K protein (t=5.397, P=0.002), Bcl-2 protein (t=6.825, P=0.000), Nrf2 mRNA (t=18.046, P=0.000), HO-1 mRNA (t=39.458, P=0.000), PI3K mRNA (t=4.979, P=0.003) and Bcl-2 mRNA (t=9.535, P=0.000) in the HG+tBHQ group were significantly higher than those in the HG group. The protein and mRNA expressions of Bax protein in the HG+tBHQ group were significantly lower than those in the HG group (t=14.998, 16.520; P=0.000, 0.000). Flow cytometry showed that the apoptosis rate of Müller cells in the HG group was significantly higher than that in the N group (t=39.905, P=0.000). The apoptosis rate of Müller cells in the HG+tBHQ group was significantly lower than that in the HG group (t=21.083, P=0.000).ConclusiontBHQ can inhibit the apoptosis of retinal Müller cells by up-regulating the expression of Nrf2, HO-1 and PI3K.
ObjectiveTo observe the protective effect of Zhicao Tea Mixture on Müller cells and the expression of inflammatory factors in mice with diabetic retinopathy.MethodsSeventy-five C57BL/6J mice were randomly divided into the normal control group, diabetes mellitus (DM) group, low concentrations group, medium concentrations group and high concentrations group, with 16 mice in each group. The diabetes model of mice in all groups except the normal control group were established by intraperitoneal injection of STZ (60 mg/kg). Four weeks after the successful modeling, the Zhicao Tea Mixture with low (30 ml/kg), medium (60 ml/kg) and high concentrations (120 ml/kg) were respectively administered by gavage. Weight and blood glucose of mice in each group were measured every two weeks. After 8 weeks, Western blot method was used to detect the mice retina Müller cells activation marker gelatinous fibrous acidic protein (GFAP). Immunofluorescence was performed to detect the expression GFAP and glutamine synthetase (GS). Real-time quantitative PCR (RT-qPCR) and ELISA were used to determine the mRNA and protein expression levels of mouse retinal VEGF, TNF-α, IL-1β and IL-6 respectively.ResultsThe weight of mice in the DM group was lower than that of the normal control group, and the blood glucose was increased. Zhicao Tea Mixture had no effect on the weight of DM mice, but had a significant hypoglycemic effect. The GFAP expression (t=38.318, P＜0.001) in the retina of mice in the DM group was increased and GS expression (t=29.737, P＜0.001) was decreased compared with the control group. The GFAP expression (t=13.677, 19.387, 16.305; P＜0.05) in the retina of mice in the low, medium and high concentrations group were decreased and GS expression (t=5.170, 19.399, 6.705; P＜0.05) were increased compared with the DM group. The expressions of retinal inflammatory factors VEGF, TNF-α, IL-1β and IL-6 in DM group all increased, while the expressions of the above-mentioned inflammatory factors in the retina of mice decreased in the low, medium and high concentrations group.ConclusionZhicao Tea Mixture can decrease the blood glucose of DM mice and reduces the diabetic retinal inflammatory response.
ObjectiveTo observe the expression of probucol on high glucose-induced specificity protein 1(SP1), kelchlike ECH associated protein1 (Keap1), NF-E2-related factor 2 (Nrf2) and glutamate-cysteine ligase catalytic (GCLC) in the cultured human müller cells and preliminary study the antioxidation of the probucol on müller cells.MethodsPrimary cultured human müller cells were randomly divided into four groups: normoglycaemia group (5.5 mmol/L glucose), normoglycaemia with probucol group (5.5 mmol/L glucose+100 μmol/L probucol), hyperglycemia group (25.0 mmol/L glucose), hyperglycemia with probucol group (25.0 mmol/L glucose + 100 μmol/L probucol). Immunofluorescence staining was used to assess distribution of SP1, Keap1, Nrf2, GCLC in human Müller cells. SP1, Keap1, Nrf2 and GCLC messenger RNA (mRNA) expression was evaluated by quantitative real-time RT-PCR (qRT-PCR). Independent sample t test was used to compare the data between the two groups.ResultsAll müller cells expressed glutamine synthetase (＞95%), which confirmed the cultured cells in vitro were the purification of generations of müller cells. The expressions of SP1, Keap1, Nrf2, and GCLC protein were positive in human müller cells. qRT-PCR indicated that SP1 (t=28.30, P＜0.000), Keap1 (t=5.369, P=0.006), and Nrf2 (t=10.59, P=0.001) mRNA in the hyperglycemia group increased obviously compared with the normoglycaemia group; GCLC (t=4.633, P=0.010) mRNA in the hyperglycemia group decreased significantly compared with the normoglycaemia group. However, SP1 (t=12.60, P=0.000) and Keap1 (t=4.076, P=0.015) in the hyperglycemia with probucol group decreased significantly compared with the hyperglycemia group; Nrf2 (t=12.90, P=0.000) and GCLC (t=15.96, P＜0.000) mRNA in the hyperglycemia with probucol group increased obviously compared with with the hyperglycemia group.ConclusionProbucol plays an antioxidant role by inhibiting the expression of SP1, Keap1 and up-regulating the expression of Nrf2, GCLC in müller cells induced by high glucose.
ObjectiveTo observe the protective effect of dl-3-n-Butylphthalide (NBP) on apoptosis of retinal Müller cells induced by hydrogen peroxide (H2O2).MethodsHuman retinal Müller cells cultured in vitro were divided into normal control group, model group (H2O2 group) and experimental group (H2O2+NBP group). The cells in the H2O2 group and H2O2+NBP group were cultured with 200 μmol/L H2O2 for 2 h. Then the culture solution of the H2O2 group replace with complete medium and the H2O2+NBP group replace with complete medium containing 1 μmol/L NBP. The normal control group was a conventional cultured cells. Müller cells were identified by immunofluorescence staining. Hematoxylin-eosin (HE) staining was used to observe the apoptosis morphological changes. MTT assay was used to detect the activity of of retinal Müller cells after after 24 h and 48 h of NBP intervention. Hoechst33258 staining was used to observe the apoptosis. LIVE/DEAD ® cell activity/cytotoxicity kit was used to detect cell viability. Dichlorofluorescein diacetate (DCFH-DA) + endoplasmic reticulum (ER) red fluorescent probe (ER-Tracker Red) double staining was used to observe the expression level of reactive oxygen species (ROS) in ER of cells. One-way ANOVA combined with Dunnett statistical method were used for data analysis.ResultsHE staining showed that the number of cells in H2O2+NBP group was higher than that in H2O2 group. MTT assay showed that after 24 h and 48 h of NBP intervention, the differences in cell viability between the normal control group and the H2O2 group, the H2O2 group and the H2O2+NBP group were statistically significant (t=28.96, 3.658, 47.58, 20.33; P＜0.001, 0.022). The results of Hoechst33258 showed that the nuclear nucleus of a few cells in the H2O2+NBP group was crescent-shaped and the nuclear fragmentation was reduced, and the blue fluorescence of the remaining cells was uniform. The LIVE/DEAD ® cell activity/cytotoxicity kit showed that the number of dead cells with red fluorescence in the H2O2 group increased significantly, and the number of viable cells with green fluorescence decreased significantly. In the H2O2+NBP group, the number of viable cells with green fluorescence increased, and the number of dead cells with red fluorescence decreased. The double staining results of DCFH-DA+ER-Tracker Red showed that the green fluorescence intensity of H2O2 group was significantly enhanced; the green fluorescence intensity of H2O2+NBP group was lower than that of H2O2 group.ConclusionNBP alleviates H2O2-induced apoptosis of human retinal Müller cells by inhibiting ROS production.
ObjectiveTo observe the effect of polypyramidine tract binding protein-associated splicing factor (PSF) towards advanced glycation end products (AGEs) induced the apoptosis of Müller cells in vitro.MethodsExperimental study. Müller cells were cultured and divided into groups according to the project design, plasmid enhanced green fluorescent protein-PSF were transfected into the cells to achieve the overexpression of PSF Müller cells in vitro, then cells were exposed to AGEs and the Morphological changes were observed by HE staining and Hoechst 33258 staining while the survival rate of cells were detected by MTT assay. The effects of PSF on AGEs-induced Müller apoptosis was measured by Cell Death Detection ELISA kit. Meanwhile, 2′,7′-dichlorofluorescin diacetate staining was performed to monitor the protective effects of PSF on AGEs-induced Müller cells ROS.ResultsThe morphology of cells in normal group was full and the cytoplasm staining was uniform. In N+AGEs group and Vec+AGEs group, cell volume decreased, cytoplasm was dense and concentrated, and eosinophilic staining was enhanced. The cell morphology of PSF+AGEs group was still full, with uniform cytoplasm staining and uniform nucleus staining. The viability of N+AGEs group, Vec+AGEs group and PSF+AGEs group were 0.42±0.11, 0.35±0.12 and 0.68±0.12. The apoptosis values were 1.08±0.16, 0.96±0.20 and 0.44±0.08. The intracellular ROS levels were 28 833.67±3 550.06, 28 356.67±4 854.81, 186 163.00±382.54. Compared with N+AGEs group and Vec+AGEs group, the cell viability of PSF+AGEs group was significantly improved (F=20.65, P=0.000), cell apoptosis value (F=43.43, P=0.000) and intracellular ROS level (F=18.86, P=0.000).ConclusionPSF overexpression play a protective role in AGEs-induced apoptosis by inhibiting the production of ROS in Müller cells.
Objective To investigate the effect of astragaloside A (AS-A) on the photoreceptor degeneration induced by sodium iodate (NaIO3) and its related mechanism. MethodsSixty healthy male C57BL/6J mice, aged 6-8 weeks, were randomly divided into normal control (NC) group, NaIO3 group, and AS-A group, with twenty mice in each group. 30 min before modeling, AS-A group mice were intraperitoneally injected with 100 μl AS-A at a dose of 100 mg/kg body weight. 30 min later, mice in NaIO3 group and AS-A group were intraperitoneally injected with 100 μl NaIO3 at a dose of 30 mg/kg body weight. Subsequently, AS-A group mice were administered AS-A twice daily at 12 h intervals until the end of the experiment. On day 1 post-modeling, zonula occludens-1 (ZO-1) immunohistochemistry was performed to observe the structure of retinal pigment epithelium (RPE) cells; real-time quantitative polymerase chain reaction (qPCR) was conducted to detect the mRNA expression of various retinal chemokine ligand-2 (Ccl2), interleukin-1 beta (Il-1β), mixed lineage kinase domain-like protein (Mlkl), receptor-interacting protein kinase 3 (Ripk3), and tumor necrosis factor (Tnf). On day 3 post-modeling, immunohistochemistry was performed to observe the expression of ionized calcium binding adaptor molecule 1 (Iba1) and glial fibrillary acid protein (GFAP) in the retina; TdT-mediated dUTP nick-end labeling (TUNEL) assay was used to detect photoreceptor cell death in each group. On day 4 post-modeling, fundus morphology of mice in each group was observed by fundus color photography and optical coherence tomography (OCT). Hematoxylin-eosin staining (HE) was used to observe the morphological structure of the retina in each group. Inter-group comparisons between two groups were conducted using independent samples t-test, while comparisons among three groups were performed using one-way ANOVA. ResultsFundus color photography and OCT examination showed that a large number of scattered yellow-white subretinal nodular structures in the fundus of NaIO3 group mice, and a large number of strong reflection areas in the RPE layer. The number of strong reflection areas in the RPE layer was reduced in the AS-A group. Immunohistochemical analysis of ZO-1 showed that ZO-1 was largely lost on the RPE cell membrane in that NaIO3 group; whereas in the AS-A group, ZO-1 was evenly distributed on the RPE cell membrane. HE staining results showed circular black deposits were visible in the RPE layer of the NaIO3 group, and the inner and outer segments of photoreceptors were severely damaged, with a significant decrease in the number of outer nuclear layer (ONL) cell nuclei; whereas in the AS-A group, the RPE layer pigments were orderly, the inner and outer segments of photoreceptors were intact, and the number of ONL cell nuclei significantly increased. The results of TUNEL staining show that numerous TUNEL-positive cell nuclei were observed in the ONL of the retina in the NaIO3 group, while the number of TUNEL-positive cell nuclei in the ONL of the retina was significantly reduced in the AS-A group, with statistically significant differences (t=2.66, P＜0.05). The analysis of qPCR data showed that compared with the AS-A group, the relative expression levels of Mlkl, Ripk3, Ccl2, Il-1β and Tnf mRNA in the retina were significantly increased in the NaIO3 group, with statistically significant differences (F=39.18, 10.66, 53.51, 41.40, 24.13; P＜0.001). Immunohistochemical staining results showed that compared with NC group and AS-A group, the positive expression of GFAP in retina of NaIO3 group was significantly increased, and the difference was statistically significant (F=9.62, P＜0.05). ConclusionAS-A antagonizes NaIO3-induced photoreceptor degeneration in part by inhibiting photoreceptor cell death and neuroinflammation. Meanwhile, AS-A treatment protects against NaIO3-triggered perturbation of retinal homeostasis.