Objective To investigate the cellular viability and mitochondrial reactive oxygen species (ROS) production of the Müller cells under high glucose condition, and explore the protection role of the 5,6-dihydrocyclopenta-1, 2-dithiole-3-thione (CPDT) on Müller cells. Methods Müller cells from Sprague Dawley rats were divided into 5 groups randomly, including 25 mmol/L normal glucose group (group A) and 65 mmol/L high glucose group (group B). High glucose group with 45, 60, 70 μmol/L CPDT and cultured them 72 hour was set as group C, D and E. Water soluble tetrazolium salt (WST)-8 was used to measure the cellular viability. Flow cytometry was used to measure the active oxygen and apoptosis index. The expression of nuclear factor erythroid 2-related factor 2 (Nrf2), hemeoxygenase-1 (HO-1), Bcl-2 and Bax protein were measured by Western blot. Results Compared with group A, the WST-8 showed that the viability of Müller cells apparently decreased in group B (t=39.59,P＜0.05). Compared with the group B, the viability of Müller cells had changes in group C (t=0.97,P＞0.05), but recovered in group D and E (t=?4.17, ?7.52;P＜0.05). Compared with group A, the FCM showed that the mitochondrial ROS levels was higher in group B (t=?30.99,P＜0.05). Compared with group B, the mitochondrial ROS levels were decreased in group D (t=27.68,P＜0.05). Compared with group A, Bax, Nrf2 and HO-1 increased (t=–11.03, –63.17, –11.44;P＜0.05), while the bcl-2 decreased in group B (t=7.861,P＜0.05). Compared with the group B, Nrf2, HO-1 and Bax decreased (t=15.11, 26.59, 6.27;P＜0.05), while the bcl-2 increased in group D (t=?6.53,P＜0.05). Conclusions Under the high glucose, CPDT may reduce the mitochondrial ROS levels and the expression of Nrf2, HO-1 and Bax protein of Müller cells. It may inhibit apoptosis through activating the Nrf2/HO-1 pathway and balancing of level of Bcl-2 protein and mitochondrial ROS.
Stem cells are crucial for embryonic development and in the maintenance of adult cellular homeostasis. Understanding the regulatory network of stem cells, including embryonic and adult stem cells, will allow us to learn the pathogenesis and possibly design novel approaches to treat many diseases (such as cancer and degeneration). The retinoblastoma (Rb) pathway controls cellular proliferation, differentiation and death. More and more evidences support an important role of Rb activity in the biology of stem and progenitor cells. Transiently inactivating Rb pathway might favor the expanding of functional stem cell populations, thus have values in the future stem cell applications.
The debate on the cell of origin of human retinoblastoma lasted for more than one century. In the recent issue of ldquo;cellrdquo;, David Cobrinikprime;s group shows that L/M cone precursors are the most likely answer as they have an intrinsic circuitry, including murine double minute 2 (MDM2), Nmyc, the nuclear receptors retinoid X receptor and thyroxine receptor 2, making them extremely sensitive to transformation following retinoblastoma gene inactivation.
ObjectiveTo observe the expression of Toll-like receptor 4 (TLR4) and inflammatory cytokines, leucocytic density and permeability in retina of diabetic rat.
MethodsA total of 106 Brown Norway rats were randomly divided into experimental group and control group with 53 rats in each group. Diabetic model was established in experimental group by intraperitoneal injection of streptozotocin, and control rats received intraperitoneal injection of an equal volume of citric acid-sodium citrate buffer. Four weeks later, the retinas were collected for further analysis. TLR4 RNA and protein expression were measured by quantitative polymerase chain reaction and Western blot. Inflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), monocyte chemo-attractant protein-1 (MCP-1), were measured by enzyme-linked immunosorbent assay in rat retina homogenate. Leukocyte density in the retina was measured by acridine orange fundus angiography. The retinal permeability was evaluated by Evans blue (EB) staining.
ResultsTLR4 expression was significantly increased in diabetic rats of experimental group compared with non-diabetic rats of control group (F=1.606, 0.789; P < 0.05). Inflammatory cytokines (TNF-α, IL-1β and MCP-1) were significantly increased in retina of diabetic rats of experimental group versus non-diabetic rat of control group (F=24.622, 5.758, 4.829; P < 0.05). The retinal leukocyte density was (6.2±0.5)×10-5, (2.2±0.3)×10-5 cells/pixel2 in experimental and control group respectively, the difference was statistically significant (F=2.025, P < 0.05). The amount of retinal EB leakage was (23.41±4.47), (13.22±3.59) ng/mg in experimental and control group respectively, the difference was statistically significant (F=21.08, P < 0.05).
ConclusionTLR4 and inflammatory cytokines expression, leucocytic density and permeability increased significantly in retina of diabetic rat.
Objective
To observe the effect of celecoxib on the expression vascular endothelial growth factors (VEGF) in diabetic rats.
Methods
Thirty-six wistar rats were used to establish the diabetic models by intraperitoneal injection with streptozotocin. The diabetic rats were divided into 2 groups: diabetic group (n=18) and celecoxib group (n=18). Celecoxib (50 mg/kg) was administered orally to the rats in celecoxib group and the physiological saline with the same volume was given orally to the rats in diabetic group. Eighteen else rats were in normal control group. All of the rats were executed 3 months later. The expression of VEGF protein was detected by immunohistochemistry method. Reverse transcription-polymerase chain reaction（RT-PCR） analysis was used to examine the expression of retinal VEGF mRNA and cyclooxygenase-2 mRNA.
Results
Lower positive expression of VEGF mRNA and cyclooxygenase-2 mRNA, weakly positive action of immunohistochemistry of VEGF, and lower expression of VEGF protein were detected in normal control group; in the diabetic group, the expression of VEGF mRNA and cyclooxygenase-2 mRNA increased obviously comparing with which in the control group (Plt;0.05), and the bly positive action of immunohistochemistry of VEGF and increased expression of VEGF protein were detected (Plt;0.01); in celecoxib group, the expression of VEGF mRNA was lower than that in the diabetic group (Plt;0.05), the expression of cyclooxygenase-2 mRNA didnprime;t decrease much (Pgt;0.05), the positive action of immunohistochemistry of VEGF decreased, and the expression of VEGF protein decreased (Plt;0.01).
Conclusion
By inhibiting the activation of cyclooxygenase-2, celecoxib can inhibit the expression of retinal VEGF mRNA and protein in diabetic rats induced by streptozotocin.
(Chin J Ocul Fundus Dis,2007,23:265-268)
Children with retinoblastoma (RB) typically survive their cancer due to advances in early diagnosis and treatment. Extraocular invasion and metastasis, and secondary malignant tumor carry a very high mortality rate. Prerequisites for metastasis include tumor initiating capacity, altered cellular adhesion and cell motility, resistance to extracellular death signals and disruption of the basement membrane and extracellular matrix. All those changes can be determined by the cell of origin and the genetic instability of the tumor, responding to the multiple layers of pressure such as hypoxia, from the tumor microenvironment or niche. The interaction between tumor cells and the tumor stroma is regulated by several metastasissuppressor proteins and microRNA. This knowledge has important implications for our understanding and the treatment of extraocular spreading of RB.
Objective To observe the choroidal thickness of patients with chronic central serous chorioretinopathy (CSC) in affected eyes and unaffected fellow eyes.Methods Forty-five chronic CSC patients diagnosed by fundus pre-set lens, fundus fluorescein angiography (FFA) and indocyanine green angiography were enrolled in this study. The patients included 36 males and nine females, with a mean age of (46.18plusmn;8.20) years, with a mean duration of (16.34plusmn;7.23) months. Thirty-six patients were affected unilaterally and nine patients affected bilaterally. The patients were divided into affected eyes group (group A, 51 eyes) and unaffected fellow eyes group (group B,39 eyes). Fifty age-, sex- and diopter- matched normal subjects (50 eyes) were enrolled in this study as control group (group C). Enhanced depth imaging (EDI) choroidal scans were obtained in all eyes by using spectral-domain optical coherence tomography. Subfoveal choroidal thickness (SFCT) and choroidal thickness at 3 mm nasal (NCT3 mm), temporal (TCT3 mm), superior (SCT3 mm), inferior (ICT3 mm) to the fovea were measured.Results The mean SFCT of group A, B and C were (436.76plusmn;87.01), (394.71plusmn;61.63), (294.86plusmn;75.30) mu;m respectively. The mean SFCT of group A and B were thicker than group C, the difference was significant among three groups (F=44.791,P＜0.001). There were difference between group A, B, C in NCT3 mm, TCT3 mm, SCT3 mm and ICT3 mm (F=15.816, 22.823, 15.147, 11.527;P＜0.001). The mean SFCT in affected eyes of unilateral patients was (416.34plusmn;79.44) mu;m, which was thicker than that in unaffected fellow eyes (t=2.897, P=0.007). Conclusion Choroidal thickness increased significantly in affected eyes and unaffected fellow eyes in patients with chronic CSC.
ObjectiveTo observe the effect of phase Ⅱenzyme inducer 5, 6-dihydrocyclopenta 1, 2-dithiole-3-thione (CPDT) on nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE) signal pathway and oxidative stress in the retina of type 2 diabetic rats.
MethodsThirty-five male Wistar rats were randomly divided into two group, normal group and model group. Model group were further randomly divided into two group, diabetic group and CPDT intervention group. There were 8 rats in the normal group and 27 rats in the model group. Diabetic group and CPDT intervention group were given high fat and high sugar diet for 2 months. After 12 hours of fasting, type 2 diabetic rat model was induced by intraperitoneal injection of low dose of streptozotocin. CPDT was added into the high fat and high sugar diets at 1 week after the diabetic model was established in the CPDT intervention group. Eight weeks after CPDT treatment, blood glucose, serum malondialdehyde (MDA), blood lipid, Nrf2 and hemeoxygenase-1 (HO-1) expression were evaluated.
ResultsType 2 diabetic model was successfully established in 25 rats, the success rate was 92.6%.The level of blood lipid of diabetic group was higher than those of the normal group (FTC=65.866, FTG=25.441, FLDL-C=38.889; P=0.000). Blood glucose was significant different between all groups (χ2=25.812, P=0.000), and was significantly higher in diabetic group than that in normal group and CPDT intervention group. The serum MDA content was significant different between all groups (F=59.545, P=0.000), and was significantly higher in diabetic group than that in normal group (t=10.523, P=0.000) and CPDT intervention group (t=7.766, P=0.000). The mRNA level of retinal Nrf2 and HO-1 was significant different between all groups (FNrf2=19.503, PNrf2=0.000;FHO-1=9.737, PHO-1=0.001), and was higher in CPDT intervention group than the diabetic group (tNrf2=3.399, PNrf2=0.002;tHO-1=2.167, PHO-1=0.039). The protein level of retinal Nrf2 and HO-1 was significant different between all groups (FNrf2=112.823, FHO-1=119.361; P=0.000), and was higher in CPDT intervention group than the diabetic group (tNrf2=6.203, tHO-1=6.388; P=0.000). Immuno-staining showed that Nrf2 and HO-1 were mainly expressed in retinal ganglion cell layer, inner plexiform layer and inner nuclear layer, and were significant different between all groups (FNrf2=16.206, FHO-1=46.790; P=0.000). They also were higher in CPDT intervention group than the diabetic group (tNrf2=3.172, PNrf2=0.003;tHO-1=6.321, PHO-1=0.000), was higher in diabetic group than that in normal group (tNrf2=2.679, PNrf2=0.011;tHO-1=3.482, PHO-1=0.001).
ConclusionCPDT may activate Nrf2/ARE pathway, induce Nrf2 and HO-1 expression, decrease serum MDA and blood glucose, and thus reduce oxidative stress injury in the retina of type 2 diabetic rats.
Objective To observe the changes of tortuosity and bifurcation angle of retinal arteries and veins in each quadrant of the posterior pole in eyes with high myopia.Methods The tortuosity and bifurcation angle of retinal vessels in each quadrant of the posterior pole in 32 patients (52 eyes) with high myopia and 22 healthy people (30 eyes) were observed and compared. The outcomes were analyzed by multivariate analysis of variance. Results The tortuosity of macular vessels and the artery from optic disc in eyes with high myopia was (1.29plusmn;1.10)times;10-4 and (5.39plusmn;1.93)times;10-5 respectively, and in the normal eyes was (4.15plusmn;2.38) times;10-4 and (9.75plusmn;4.99)times;10-5 respectively; there was significant difference between the two groups （t=1.99, 2.00;Plt;0.05）. The bifurcation angle of superior nasal and inferior nasal retinal arteries in eyes with high myopia was（66.17plusmn;14.04）deg; and (61.20plusmn;11.02) deg; respectively, and in the normal eyes was （77.66plusmn;14.12）deg; and (85.86plusmn;16.45) deg; respectively; there was significant difference between the two groups （F=0.77, 0.83; Plt;0.05）. The bifurcation angle of superior temporal and inferior temporal retinal veins in eyes with high myopia was（92.39plusmn;20.36）deg; and (83.56plusmn;23.50) deg; respectively, and in the normal eyes was （79.45plusmn;15.94）deg; and (70.59plusmn;17.27) deg;; there was significant difference between the two groups （F=2.34, 1.83; Plt;0.05）.Conclusions The vessel tortuosity of retinal arteries and the vessels extending from the optic disc to macula is smaller in eyes with high myopia, while the venous tortuosity has no change. The bifurcation angle of retinal arteries in the superior nasal and inferior nasal field was smaller in eyes with high myopia, while the venous tortuosity has no change. The bifurcation angle of retinal veins in the superior temporal and inferior temporal field was larger in eyes with high myopia.
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.
