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 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 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.
ObjectiveTo investigate the effects of targeted regulation of SMAD9 expression by bone morphogenetic protein 4 (BMP4) on Müller cell migration, reactive oxygen species (ROS) generation and vascular endothelial growth factor (VEGF) expression. MethodsMüller cells cultured in vitro were divided into normal control group, BMP4 group, BMP4+ no-load plasmid group (BMP4+NC group) and BMP4+SMAD9 small interference plasmid group (BMP4+siSMAD9). Cells in BMP4 group, BMP4+NC group and BMP4+siSMAD9 group were induced by adding 100 ng/ml BMP4 into cell medium for 24 h. Subsequently, BMP4+NC group was transfected with empty plasmid. BMP4+siSMAD9 group was transfected with SMAD9 small interference plasmid for 48 h. The effect of BMP4 on Müller cell migration was determined by cell scratch test. The effect of BMP4 on the production of ROS in Müller cells was detected by flow cytometry. Western blots and real-time quantitative fluorescence polymerase chain reaction (qPCR) were used to detect the relative mRNA expression levels of glutamine synthetase (GS) and glial fibrinoacidic protein (GFAP) in Müller cells. VEGF expression in Müller cells was detected by immunofluorescence. One-way analysis of variance was used to compare groups. ResultsThe results of cell scratch test showed that the cell mobility of BMP4+siSMAD9 group was significantly lower than that of BMP4 and BMP4+NC group, and the difference was statistically significant (F=68.319, P＜0.001). Flow cytomethods showed that the level of ROS in BMP4+siSMAD9 group was significantly lower than that in BMP4 and BMP4+NC group, and the difference was statistically significant (F=52.158, P＜0.001). Western blot and qPCR results showed that the protein levels of GS and GFAP (F=42.715, 36.618) and mRNA relative expression levels (F=45.164, 43.165) in BMP4+siSMAD9 group were significantly lower than those in BMP4 and BMP4+NC group. The difference was statistically significant (P＜0.01). The results of immunofluorescence detection showed that the intracellular VEGF fluorescence intensity in BMP4 group and BMP4+NC group was significantly higher than that in BMP4+siSMAD9 group, and the difference was statistically significant (F=46.384, P＜0.05). ConclusionTargeted regulation of SMAD9 expression by BMP4 can up-regulate VEGF expression and promote the migration and ROS production of Müller cells.
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 effectiveness of talonavicular-cuneiform joint fusion with iliac bone grafting and without bone grafting in the treatment of Müller-Weiss diseases (MWD). Methods The clinical data of 44 patients (44 feet) with MWD who received talonavicular-cuneiform joint fusion between January 2017 and November 2022 and met the selection criteria was retrospectively analyzed. Among them, 25 patients were treated with structural iliac bone grafting (bone grafting group) and 19 patients without bone grafting (non-bone grafting group). There was no significant difference (P>0.05) in age, gender composition, body mass index, disease duration, affected side, Maceira stage, and preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS) score, anteroposterior/lateral Meary angle, and Pitch angle between the two groups. Operation time, operation cost, and postoperative complications were recorded in the two groups. AOFAS and VAS scores were used to evaluate the function and pain degree of the affected foot. Meary angle and Pitch angle were measured on the X-ray film, and the joint fusion was observed after operation. The difference (change value) of the above indexes before and after operation was calculated for comparison between groups to evaluate the difference in effectiveness. Results The operation was successfully completed in both groups, and the incisions in the two groups healed by first intention. The operation time and cost in the bone grafting group were significantly more than those in the non-bone grafting group (P<0.05). All patients were followed up. The median follow-up time was 41.0 months (range, 16-77 months) in the non-bone grafting group and 40.0 months (range, 16-80 months) in the bone grafting group. There was skin numbness of the medial dorsalis of the foot in 1 case, internal fixation stimulation in 2 cases, and pain at the iliac bone harvesting area in 1 case of the bone grafting group. There was skin numbness of the medial dorsalis of the foot in 1 case and muscle atrophy of the lower limb in 1 case of the non-bone grafting group. There was no significant difference in the incidence of complications between the two groups (P>0.05). At last follow-up, the AOFAS scores of the two groups significantly improved when compared with those before operation, while the VAS scores significantly decreased, the anteroposterior/lateral Meary angle and Pitch angle significantly improved, and the differences were significant (P<0.05). There was no significant difference in the change values of outcome indicators between the two groups (P>0.05). There was no delayed bone union or bone nonunion in both groups, and joint fusion was achieved at last follow-up. Conclusion In the treatment of MWD, there is no significant difference in effectiveness and imaging improvement of talonavicular-cuneiform joint fusion combined with or without bone grafting. However, non-bone grafting can shorten the operation time, reduce the cost, and may avoid the complications of bone donor site.
Objective To evaluate the short-term effectiveness of talonavicular arthrodesis for Müller-Weiss disease. Methods Between May 2013 and February 2015, 13 patients with Müller-Weiss disease were treated with talonavicular arthrodesis. There were 11 females and 2 males with an average age of 59 years (range, 42-67 years). The disease duration was 8-20 years (mean, 13 years). According to Maceira stage, there were 7 cases of stage Ⅲ, 6 cases of stage Ⅳ. The foot longitudinal arch height measured on weight-bearing X-ray films was (43.1±1.8) mm; the Meary angle and talocalcaneal angle measured on lateral X-ray films were (–2.8±2.3)° and (5.8±2.4)°, respectively; the calcaneal valgus angle measured on Saltzman position X-ray films was (–2.0±0.7)°. The American Orthopaedic Foot and Ankle Society (AOFAS) score was 43.5±12.4, and visual analogue scale (VAS) score was 7.3±1.5. Results All the patients were followed up 14-39 months (mean, 20 months). The symptoms of foot pain and intermittent claudication disappeared in all patients. All cases achieved bony union, the fusion time was 12-16 weeks (mean, 13 weeks). There was no complications such as wound infection, skin necrosis, or internal fixator broken. At last follow-up, the foot longitudinal arch height, Meary angle, talocalcaneal angle, and calcaneal valgus angle were (52.5±2.2) mm, (1.3±2.2)°, (16.5±3.7)°, and (0.4±0.7)°, respectively; the AOFAS score and VAS score were 83.8±9.1 and 1.0±0.4, respectively; all were significantly improved when compared with preoperative ones (P<0.05). Conclusion If the subtalar and calcaneocuboid joints are relatively healthy, talonavicular arthrodesis may be a reliable and effective surgical option for Müller-Weiss disease that is resistant to conservative treatment.