Anti-VEGF reduces inflammatory features in macular edema secondary to retinal vein occlusion

AIM: To investigate the anti-inflammatory effect of intravitreal injection of anti-vascular endothelial growth factor(anti-VEGF) in patients with macular edema secondary to retinal vein occlusion(RVO-ME).METHODS: Twenty-eight eyes from twenty-eight treatment-na?ve patients(14 males and 14 females) with RVO-ME were included in this retrospective study.The retinal vein occlusion(RVO) was comprised of both central retinal vein occlusion(CRVO,n=14) and branch retinal vein occlusion(BRVO,n=14).Intravitreal injection of anti-VEGF reagents were administered monthly for three consecutive months,in which 18 patients were injected with ranibizumab and 10 patients were injected with conbercept.All eyes were imaged with optical coherence tomography angiography(OCTA) at baseline and 1wk after monthly intravitreal anti-VEGF injection.The visual acuity(VA),central macular thickness(CMT),the number of hyperreflective foci(HRF) recognized as an inflammatory sign in OCT images,and non-perfusion area(NPA),were compared before and after anti-VEGF treatments.RESULTS: The mean interval between baseline and follow-up was 29.4±0.79(range,27-48)d.Compared with the baseline,the VA improved(log MAR 1.5±0.1 vs 0.8±0.1,P<0.05) and CMT decreased(460±34.0 μm vs 268.8±12.0 μm,P<0.05),significantly,after antiVEGF treatment.The number of HRF was decreased significantly(76.5±4.8 vs 47.8±4.3,P<0.05) after antiVEGF treatment.CONCLUSION: Anti-VEGF therapy is effective in treating RVO-ME.The mechanisms for the decreased HRF and the reduction of NPA by anti-VEGF therapy merits further exploration.

Annexin A2 silencing enhances apoptosis of human umbilical vein endothelial cells in vitro

Objective:To study the effects of inhibited Annexin A2(ANXA2) on human umbilical vein endothelial cells(HUVECs) in vitro.Methods:Short hairpin RNA(shRNA) targeting ANXA2 was designed and cloned into double marked lentvirial vector GV248 for RNAi to generate the recombinant expression plasmids,which were stably transfected into HUVECs.The protein and mRNA expression levels of ANXA2 were analyzed by western blotting and realtime polymerase chain reaction,respectively.Cell proliferation(cell counting kit-8 assay),apoptosis(flow cytometry analysis),the expression(western blotting) and the activity of easpases(enzyme-linked immunosorbent assay) were used to assess the effects of silencing ANXA2 on HUVECs in vitro.Results:The plasmids to express ANXA2-specific shRNA were constructed and were infected into HUVEC resulting in the stably transfected experimental(ANXA2-shRNA),control(eontrol-shRNA) and mock(no plasmid) cell lines,which were verified with western blot and real-time PCR.HUVEC/ANXA2-shRNA showed an inhibition rate 91.89%of ANXA2 expression compared to the mock HUVEC.ANXA2 silencing cell strain obviously presented a lower cell proliferation activity compared to the control and mock HUVECs,with an inhibition rate 82.35%on day 7 in vitro.FACS analysis indicated that the HUVEC/ANXA2-shRNA cells undergoing apoptosis increased by 102.61%compared to the mock HUVECs(P<0.01).Moreover,the activity levels of caspase-3,caspase-8 and caspase-9in HUVEC/ANXA2-shRNA cells were increased and the activated cleaved caspase-3,cleaved Caspase-8 and cleaved caspase-9 were upregulated evidently compared with that of the control and mock HUVECs by 56.29%,89.59%and 144.58%(P<0.01).Conclusions:shRNAmediated silencing of ANX A2 could not only be able to suppress HUVECs:proliferation but to upregulate the enzyme activity of easpases,which bring to an increase of cell apoptosis This work suggested that ANX A2 may represent a useful target of future molecular therapies.

Is Iba-1 protein expression a sensitive marker for microglia activation in experimental diabetic retinopathy?

AIM:To investigate the changes of Iba-1 and other potential markers for microglia activation in experimental diabetic retinopathy(DR).METHODS:Male Sprague-Dawley rats were rendered diabetes via intraperitoneal injection of streptozotocin.The retinas were harvested at 1 to 24 wk after diabetes onset.Hypoxia-treated mouse microglial cell line(BV2 cells)was employed as the in vitro model to mimic diabetic condition.The expressions of Iba-1,CD11 b,ICAM-1 as well as the inflammatory factors were examined with real-time polymerase chain reaction,Western blot and immunofluorescence both in vivo and in vitro.RESULTS:Compared with age-matched normal control,the number of microglia(Iba-1 positive immunostaining)in diabetic rat retinas was increased from 1 to 24 wk of diabetes,which was most obvious at 12 wk of diabetes.Iba-1 protein expression detected by Western blot was increased slightly in diabetic rat retinas compared with that in age-matched normal control;however,there was statistically significant between two groups only at 2 wk after diabetes onset.The m RNA expression of Iba-1 was decreased significantly at 2 and 4 wk of diabetic rat retinas,and remained unchanged at 8 and 12 wk of diabetes.In BV2 cells,there was no significant change for the Iba-1 protein expression between normoxia and hypoxia groups;however,its m RNA level was decreased significantly under hypoxia.To further characterize microglial activation,F4/80,CD11 b and inflammatory factors were detected both in vivo and in vitro.Compared with normal control,the expressions of F4/80 and CD11 b as well as the inflammatory factors,such as ICAM-1,i NOS,COX2,IL-1βand IL-6,were increased significantly both in vivo and in vitro.CONCLUSION:Iba-1 protein expression might not be a sensitive marker to evaluate the activation of microglia in experimental DR.However,Iba-1 immunostaining,in combination with other markers like CD11 b and ICAM-1,could be well reflect the activation of microglia.Thus,it is of great importance to explore other potential marker to evaluate the activation of microglia.

A 4H-SiC merged P–I–N Schottky with floating back-to-back diode

A novel 4 H-Si C merged P–I–N Schottky(MPS)with floating back-to-back diode(FBD),named FBD-MPS,is proposed and investigated by the Sentaurus technology computer-aided design(TCAD)and analytical model.The FBD features a trench oxide and floating P-shield,which is inserted between the P+/N-(PN)junction and Schottky junction to eliminate the shorted anode effect.The FBD is formed by the N-drift/P-shield/N-drift and it separates the PN and Schottky active region independently.The FBD reduces not only the Vturn to suppress the snapback effect but also the Von at bipolar operation.The results show that the snapback can be completely eliminated,and the maximum electric field(Emax)is shifted from the Schottky junction to the FBD in the breakdown state.

Research on mouse model of grade Ⅱ corneal alkali burn

AIM： To choose appropriate concentration of sodium hydroxide（Na OH） solution to establish a stable and consistent corneal alkali burn mouse model in grade II.·METHODS： The mice（n =60） were randomly divided into four groups and 15 mice each group. Corneal alkali burns were induced by placing circle filter paper soaked with Na OH solutions on the right central cornea for 30 s.The concentrations of Na OH solutions of groups A, B, C,and D were 0.1 mol/L, 0.15 mol/L, 0.2 mol/L, and 1.0 mol/L respectively. Then these corneas were irrigated with 20 m L physiological saline（0.9% Na Cl）. On day 7 postburn, slit lamp microscope was used to observe corneal opacity,corneal epithelial sodium fluorescein staining positive rate, incidence of corneal ulcer and corneal neovascularization, meanwhile pictures of the anterior eyes were taken. Cirrus spectral domain optical coherence tomography was used to scan cornea to observe corneal epithelial defect and corneal ulcer.·RESULTS： Corneal opacity scores（ x ±s） were not significantly different between the group A and group B（P =0.097）. Incidence of corneal ulcer in group B was significantly higher than that in group A（P =0.035）.Incidence of corneal ulcer and perforation rate in group B was lower than that in group C. Groups C and D had corneal neovascularization, and incidence of corneal neovascularization in group D was significantly higher than that in group C（P =0.000）.·CONCLUSION： Using 0.15 mol/L Na OH can establish grade II mouse model of corneal alkali burns.