Inhibition Of Corneal Neovascularization By Chitosan Oligosaccharide/tannic Acid Materials

Objective To investigate the in vitro activity and effect on corneal neovascularisation(CNV)of chitosan oligosaccharide/tannic acid(COS/TA)materials.Methods1.Synthesis of COS/TA materials and study of their physical and chemical properties by Fourier transform infrared absorption spectrometer(FT-IR)analysis,X-ray diffractometer(XRD)scanning,particle size measurement and scanning electron microscope(SEM)observation.,respectively.2.The materials were co-cultured with lipopolysaccharide(LPS)-induced mouse macrophages(RAW264.7)and the expression levels of interleukin-6(IL-6),tumor necrosis factor-α(TNF-α)and IL-10 was measured by ELISA.3.DPPH and ABTS radical scavenging experiments to calculate the radical scavenging rate and scavenging capacity of COS/TA materials.4.The materials were co-cultured with human umbilical vein endothelial cells(HUVECs)to measure cell proliferation activity by CCK-8 assay,migration activity by cell scratch assay and vascular endothelial growth factor-A(VEGF-A)expression level by ELISA.5.Twenty-four SD rats were random Ly divided into blank group,control group and experimental group,eight rats in each group.The blank group was not treated,the control group and experimental group were treated with regular drops of saline and COS/TA materials eye drops respectively after corneal alkali burn.Slit lamp examinations were performed and recorded at day3,day7 and day14 of the experimental process,and the CNV areas of the control and experimental groups were calculated.Sections of corneal tissue were stained with HE and labelled with CD31 immunofluorescence at day3,day7 and day14 of the experimental process,the growth of CNV was observed under the microscope respectively.Results1.FT-IR analysis proved the successful synthesis of COS/TA materials,XRD scans confirmed the non-crystalline structure of COS/TA materials,and particle size measurements and SEM observations the COS/TA materials to be homogeneous,three-dimensional particle structures at the nanoscale.2.COS/TA materials reduced the expression levels of IL-6 and TNF-α in LPS-induced mouse macrophages(p<0.001,p<0.01),and had no effect on the expression level of IL-10(p>0.05).3.COS/TA materials had good oxygen radical scavenging ability.4.COS/TA materials inhibited the proliferation,migration and VEGF-A expression of HUVECs.5.In the alkali burn-induced CNV experiment in rats,slit lamp microscopic observations showed that the CNV growth was gentler and the CNV area was lighter in the experimental group than in the control group at day3,day7 and day14(p<0.05,p<0.01,p<0.05).HE staining and CD31 fluorescence staining at day7 and day14 showed no vascular structures in the corneas of the blank group,while a large number of coarse neovascularizations were visible in the corneas of the control group and only a little neovascularization was visible in the experimental group.ConclusionCOS/TA materials exhibit anti-inflammatory,antioxidant and anti-neoangiogenic activity in vitro and inhibit alkali burn-induced CNV in rats.