ABSTRACT
Background The pathogenesis and mechanism research of corneal neovascularization is of important significance for the prevention and management of corneal neovascularization.Some relative researches are being performed on non-corneal neovascularization-derived vascular endothelial cells, so the results are affected to a certain extent.Objective This study was to isolate and culture vascular endothelial cells from experimental corneal neovascularization tissue and detect the expression of chemokine receptors in vitro.Methods Corneal neovascularization models were established on 10 SPF male BALB/c mice with the age of 7-8 weeks by sticking the filter papers with NaOH on the central corneas, and then the immunofluorescence technique was use to assay the CD31 expression in corneal flatmount 2 weeks after modeling.Corneal pieces were made in 2 weeks after alkali burn and then were digested by collagenase type D.Vascular endothelial cells were isolated from neovascularized tissue by affinity purification using magnetic beads coated with anti-CD31.The cells were cultured on fibronectin-coated walls and then identified by immunocytochemistry.Reverse transcription-PCR was employed to detect the expressions of chemokine receptors in the cells.The use and care of the animals complied with ARVO Statement and this experimental procedure was approved by Soochow University Animal Care Committee.Results Corneal neovascularization occurred at 7 days and peaked at 2 weeks after modeling, and immunofluorescence exhibited the green network-like fluorescence for CD31 antibody in corneas.The cells grew against the wall 2 hours after culture with the polygon shape and large dimension, and the growth obviously quickened after passage.The cultured cells showed the positive response for CD31 antibody, showing the brown dye in cytoplasm,in contrast,the expression of CD31 was absent in corneal stromal cells.Chemokine receptors were positively expressed in the cells with the strongest expression levels in CCR1 ,CCR2,CCR3 and CCR4 mRNA and the weakest expression levels in CCR9,CXCR4 and CXCR5 mRNA,while CXCR3, CCR6, CCR10 and CX3CR1 mRNA were expressed with the moderate intensity.Conclusions Vascular endothelial cells can be obtained from experimental neovascularized corneas by affinity purification and express chemokine receptors,which facilitate the study of their biological properties.
ABSTRACT
Purpose: To compare the effects of bevacizumab applied either subconjunctivally or topically, in a rat model of corneal neovascularization induced by alkali burn. Methods: The right corneas of 24 Wistar-Albino rats were cauterized with silver nitrate sticks. The rats were divided randomly and equally into three groups: no treatment control (n=8), subconjunctival bevacizumab treatment (n=8), and topical bevacizumab treatment (n=8). Immediately following cauterization, the subconjunctival group was treated with a 0.05 ml (1.25 mg) bevacizumab subconjunctival injection. The topical group was treated with 10 mg/ml bevacizumab twice daily, and the control group received subconjunctival saline injections twice daily. The burn stimulus and neovascularization scores were evaluated using a technique previously described by Mahoney and Waterbury. Digital photographs were obtained before the eyes were enucleated and corneal sections were then analyzed by histopathology. Results: The mean burn stimulus score was 1.86 ± 0.6 and there was no statistical difference between the groups (p=0.730). The mean neovascularization scores in the subconjunctival and topical bevacizumab groups were statistically lower than the control group (p<0.05). The mean percentage area of corneal neovascularization was 82.5 ± 22.1 in the control group, 42.7 ± 15.0 in the subconjunctival group, and 55.8 ± 18.2 in the topical group. The differences between the control and treatment groups were statistically significant (p<0.05). Histopathology showed that the treatment groups presented less neovascularization, inflammation, and fibroblast activity than the control group (p<0.05). Conclusions: This study demonstrates that both subconjunctival and topical administrations of bevacizumab inhibit corneal neovascularization and decrease inflammation and fibroblast activity in a rat model of corneal neovascularization induced by alkali burn. .
Objetivo: Comparar o efeito de bevacizumab aplicado subconjuntival e topicamente em um modelo de neovascularização de córnea de ratos induzida por queimadura alcalina. Métodos: Córneas direitas de 24 ratos Wistar-Albino foram cauterizados por nitrato de prata. Os indivíduos foram divididos aleatoriamente e igualmente em três grupos: controle (n=8), o bevacizumab subconjuntival (n=8), o bevacizumab tópico (n=8). Imediatamente após a cauterização, 0,05 ml (1,25 mg) de bevacizumab foi injetado no grupo subconjuntival. Grupo tópico foi inculcado com 10 mg/ml de bevacizumab duas vezes por dia. O grupo controle recebeu solução salina normal, topicamente, duas vezes ao dia. A graduação do estímulo da queimadura e a graduação da neovascularização foram avaliados utilizando a técnica descrita por Mahoney e Waterbury. Fotografias digitais foram obtidas dos olhos serem enucleados. Seções da córnea foram analisadas por histopatologia. Resultados: A média da graduação do estímulo da queimadura foi de 1,86 ± 0,6 e não houve diferença estatisticamente entre os grupos (p=0,730). As médias das graduações da neovascularização no grupo bevacizumab subconjuntival e no grupo bevacizumab tópico foram estatisticamente menores do que o grupo controle (p<0,05). A percentagem média de área de neovascularização da córnea foi de 82,5 ± 22,1 no grupo controle, 42,7 ± 15,0 no grupo subconjuntival e 55,8 ± 18,2 no grupo tópico. As diferenças entre os grupos de tratamento e grupo de controlo foram estatisticamente significativos (p<0,05). A histopatologia mostrou que os grupos de tratamento apresentavam menos neovascularização, inflamação e atividade de fibroblastos do que o grupo controle (p<0,05). ...
Subject(s)
Animals , Male , Rats , Antibodies, Monoclonal, Humanized/administration & dosage , Antibodies, Monoclonal/administration & dosage , Corneal Neovascularization/drug therapy , Cornea/blood supply , Cornea/pathology , Corneal Neovascularization/chemically induced , Disease Models, Animal , Injections, Intraocular , Random Allocation , Rats, WistarABSTRACT
Background Intracorneal macrophages play a critical role in corneal neovascularization (CNV)by secreting relative chemokines.But macrophages are characteristic by heterogeneity which has different biologic functions under different induction or stimulation from microenvironment.Objective This study was to detect the effects of chemokine (C-X3-C motif) ligand 1 (CX3CL1) and chemokine (C-C motif) ligand 2 (CCL2) on macrophages in vitro.Methods CNV was induced by corneal alkali burn in the left eyes of 20 male BALB/c mice aged 7-8 weeks.The CNV was evaluated under the slit lamp microscope 4 days after alkali burn,and then the corneal sections were prepared after mice were sacrificed.The expressions of CCR2 and CX3CR1 in the corneal specimens were detected by histo-fluorescence staining.Human peripheral blood mononuclear cells were separated using density gradient centrifugation and incubated in RPMI-1640 medium containing 10％ fetal bovine seruml(FBS) with 30 μg/L granulocyte-macrophage colony-stimulating factor (GM-CSF).The cells were divided into CD68 +CCR2 group and CD68+CX3CR1 group,and the percentage of the CX3CR1 and CCR2 expressions in the infiltrated macrophages of corneal specimens and human monocyte-derived macrophages was assayed by flow cytometry.The cultured cells were stimulated using human recombinant CX3CL1 and CCL2 proteins,and real-time PCR was used to detect the relative expressions of angiogenesis-related factors in macrophages.Results CNV was found in corneas 4 days after alkali burn and the CNV onsets from corneal limbus to central zone observed by a slit lamp.CCR2 and CX3CR1 were expressed in the F4/80-positive macrophages in alikali burned corneas.The macrophages grew for two weeks and appeared more dead cells in without GM-CSF group,but in GM-CSF induced group,the number of macrophages was increased.The percentage of CX3CR1-positive cells was 75％ and that of CCR2-positive cells was 45％.Real-time PCR showed that expression level of vascular endothelial growth factor (VEGF) mRNA increased and that ADAMTS-1 mRNA or TSP-1 mRNA decreased on macrophages after CCL2 stimulation,with significant differences in the 150 mg/L CCL2 group compared with the control group (t =-5.09,P =0.03 ; t =3.01,P =0.04 ; t =4.27,P =0.02).However,the VEGF mRNA expression decreased and ADAMTS-1 mRNA and TSP-1 mRNA increased after CX3CL1 stimulation,showing significant differences between the 150 mg/L CX3CL1 group and the control group (t=6.35,P=0.O2;t=-2.92,P=0.04; t=-3.81,P=0.03).Conclusions These results suggest that the macrophages have high heterogeneity.CCL2-and CX3CL1-expressing macrophages can regulate the expressions of angiogenesis-related factors.Macrophage chemokine signal may be a good target for treatment of neovascular ocular disease.