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Many studies have confirmed that gut microbiota plays a pivotal role in human health. It affects multiple organ systems other than the digestive tract. The bidirectional communication between the microbiota and the human body is finely orchestrated by different systems, including the nervous, immune, and endocrine systems. Moreover, intestinal flora imbalance plays an important role in the occurrence and development of ocular diseases such as glaucoma, uveitis, diabetic retinopathy, and age-related macular degeneration. Multiple microbiota and related metabolite(involving both microbe and host)both impact ocular diseases in animal models and demonstrate striking associations in clinical studies. Therefore, modulation of gut microbiota and metabolite may be beneficial for the maintenance of ocular homeostasis and the treatment of related ocular diseases. This article reviews the recent progress in the studies on relationship between intestinal microorganisms and several common ocular diseases, providing therapeutic targets for potential translational investigations within this research field.
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Background Though nitric oxide (NO) and NO synthase (NOS) have a critical role in angiogenesis,their effects on corneal neovascularization (CNV) and mechanism need to be further explored.Objective The aim of this study was to explore the effects of NOS and its antagonist,Nw-nitro-L-arginine methyl ester (L-NAME) on experimental CNV in mice,and investigate the influence of NOS and L-NAME on the tube formation of human retinal endothelial cells (RECs) in vitro.Methods The CNV models were established in the left eyes of 36 male BALB/c mice aged 7-8 weeks by application of the filter paper with NaOH in the center of corneas.The mice were randomized into two groups.L-NAME of 10 g/L (0.5 ml) was intraperitoneally injected 1 week before induction of CNV three times a week for three weeks in the mice of the L-NAME injection,and PBS was used in the same way in the control group.CNV was examined under the slit lamp biomicroscope 2,4,7,14 days after NaOH burn.The expression of CD31 in the CNV was assayed to calculate the ratio of CNV area and total corneal area using whole mount technique.The expression of NOS mRNA in the corneal tissue was detected by reverse transcriptase polymerase chain reaction (PCR),and VEGF expression in the human RECs was assayed by Western blot.The vessel formation number of cultured human RECs with or without L-NAME was performed by matrigel in vitro.Grouped t test was used to compare the differences of the parameters between the two groups.Results CNV developed and peaked 2 weeks after the application of NaOH on the mice corneas,and the CNV was obviously less in the L-NAME group compared with the control group.The expression of NOS mRNA in the corneas (NOS mRNA/ GAPDH mRNA)was significantly lower in the L-NAME group than that of the control group 2,4,7 days after CNV induction (t =19.481,t=22.059,t=10.961,all at P＜0.01).The ratio of the CD31 positive area in whole corneal area was 0.59± 0.01 in the L-NAME group,and that of the control group was 0.78±0.10,showing a significant difference between the two groups (t =3.078,P＜0.05).Western blot assay showed that the relative expression of VEGF protein in human RECs was declined in the L-NAME group compared with the control group 0,2,4,7 days,with statistically significant differences in 4 days and 7 days after NaOH burn(t=7.696,t=17.953,both at P＜0.01).The number of vessel network was 46.33±1.86 in the L-NAME group and 64.00±4.51 in the control group,with a significant difference between them (t =3.623,P＜0.05).Conclusions NOS participated in the pathogenesis and aggravation of CNV induced by NaOH.L-NAME arrests CNV formation and human RECs tube formation through down regulating the VEGF expression and NOS activity.
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Background Stromal-derived factor 1α /chemokine receptor 4(SDF-1α/CXCR4) axis is one of the important signals which mediates several different activities such as chemotaxis,adhesion,proliferation and survival resulting in recruitment to sites of immune and inflammatory reactions.Considerable evidence suggests that CXCR4/SDF-1α axis is involved in tumor angiogenesis and plays a key role in the development of ocular neovascularization.Objective The purpose of this study was to explore the effect of CXCR4 antagonist on the development of cxperimental corneal neovascularization(CNV).Methods CNV model was established in the left eye of 8-weekold clean BALB/c mouse by putting the filter with 1 mol/L NaOH at the central cornea for 40 seconds.The animals were randomizcd into hyaluronate group and CXCR4 antagonist group,and the edydrops was topically administered respectively on the day of modeling 4 times per day for 14 days.CNV was examined under the slit lamp at the fourteenth day,and then the corneal suspension and section were made.Expressions of CXCR4 mRNA and protein in corneas were detected using RT-PCR and Western blot.The CD31 level in cornea was assayed by flowcytometry and immunochemistry.The expression of VEGF in burned corneas and suspension from mouse peritoneal macrophages stimulated with CXCR4 antagonist in vitro was detected by ELISA.The use of the animal followed Ragulations for the Administration of Affairs Concerning Experimental Animals by State Science and Technology Commission.Results Two weeks after corneal alkali burn,the growth of CNV peaked under the slit lamp.Compared with hyaluronate group,CNV was obviously decreased in the CXCR4 antagonist group.Immunochemistry showed that intensity of positive staining for CD31 in cornea in the CXCR4 antagonist group was weaker than the hyaluronate group.Flowcytometry clarified that CD31 positive cells rate was 9.50％ ±2.34％ in the CXCR4 antagonist group and 17.50％ ±3.16％ in the hyaluronate group,showing a significant difference between them (t=-7.312,P＜0.05).In 2,4,7 days after cornea alkali burn,the expressions of CXCR4 mRNA and protein were significantly enhanced in burn corneas compared with normal corneas(P＜0.01 ;P＜0.05).ELISA showed that the VEGF expression level in corneal tissue and supernatant of mouse peritoneal macrophages in vitro were significantly lower in the CXCR4 antagonist group than that of hyaluronate group(t =10.927,5.151,P＜0.05).The expression level of VEGF in corneal suspension was lower in the GM-CSH+CXCR4 antogonist group than that in the GM-CSH group (P＜0.05).Conclusions CXCR4 antagonist can reduce experimental CNV by down-regulating VEGF expression in cornea.
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BackgroundIt has been proved that as a chemokine,interferon-inducible protein-10(IP-10)can regulate the immuno-inflammatory reaction.Some new researches showed that IP-10 also played role in regulating the neovascular vessel formation.Corneal neovascularization (CNV) is associated with multiple cellular factors,but its mechanism is below clear.Objective The present study was to address the roles of exogenous mouse IP-10 in alkali burn-induced CNV.Methods Eighty-two SPF BALB/c mice were used in this experiment and grouped according to random number table.The corneal alkali burn models were established by putting the filter paper with 1 mol/L NaOH at the central corneas of the left eyes for 40 seconds.10 mg/L IP-10 was topically administered from the first day or 14 days after modeling in the early intervene group( 10 eyes)or middle-late intervene group(5 eyes).CNV area was measured as a percentage of whole cornea.0.2％ sodium hyaluronate(HA) as vehicle was utilized in the model control group.Angiogenic factor expression in corneal tissue in the early intervene group was quantified by reverse transcriptase polymerase chain reaction (RT-PCR)and compared with model control group.All animal experiments were performed in accordance with the Association for Research in Vision and Ophthalmology Statement for the Use of Animals in Ophthalmic and Vision Research and complied with the standards of Guidelines for the Care and Use of Laboratory Animals of Soochow University. ResultsThe CNV percentage was(88.67±10.22) ％ in the model control mice,showing a significant increase in comparison with that of IP-10 early intervene group (70.06±12.21)％ (t=3.77,P=0.00).In 21 days after corneal alkali burn,the CNV percentage was(87.33±13.47)％ in the model control mice,and that of the IP-10 middle-late intervene group was ( 86.56± 12.47 ) ％ without significant difference between them ( t =1.26,P＞0.05 ).Two days or four days after IP-10 early intervene,the expressions of chemokine receptor type 3 ( CXCR3 ) in corneal tissue were significant higher than model control group( t =3.13,3.07,P＜0.05 ),but the expressions of vascular endothelial growth factor (VEGF) in cornea were lowed ( t =5.99,6.27,P＜0.01),and so were transforming growth factor-β1 (TGF-β1) (t =8.50,P＜0.01;t =4.53,P＜0.05).Conclusions The early topical administration of the exogenous mouse IP-10 can inhibit CNV by up-regulating CXCR3 expression and down-regulating VEGF and TGF-β1 expression in cornea.However,middle-later usage of the IP-10 is uneffective.