The Inhibitory Effect Of Different Concentrations Of KH902 Eye Drops On Corneal Neovascularization Induced By Alkali Burn

Background:The cornea is considered transparent because it has no vessels.Many inflammatory,infectious,traumatic,ischemia,degenerative disorders may induce CNV formation in corneas.VEGF has shown to be affected in CNV formation.Anti-VEGF drugs could inhibit the growth of CNV.KH902 is a new anti-VEGF drug.This study was to investigate the effects of different concentrations of KH902 for inhibiting CNV induced by alkali burn on rabbits.Method:1.A total of 48 adult New Zealand(left eyes)were used to produce corneal alkali burn models.The ratio of female to male was 1:1.They were randomly divided into 4 groups by using different concentrations of KH902 eye drops immediately after injuries:Group A 2.5 mg/m L,Group B 5 mg/m L,Group C 10 mg/m L and Group D saline solutions,50?l each time and 3 times a day.On Day 7,14,28,anterior segment photographs were captured,the areas of CNV were calculated,the pathological examinations were given,and the VEGF levels were measured by immunohistochemistry.Corneal laser confocal microscopy was performed on Day 3,7,14,and 28 to observe the morphology of corneal tissue,CNV growth in central region,and inflammatory cell density.The numbers of corneas in each group producing CNV and ulcers in the central region on Day 7,14 and 28 were recorded.The densities of inflammatory cells were measured by the confocal microscopy.Data were statistically analyzed by repeated measures analysis of variance,and data comparison between two groups was performed using the SN K-q test.P < 0.05 was considered statistically significant.Result:1.Macropathology: on Day 7,a small amount of CNV were grown in the periphery corneas of the four groups,and Group D has the highest density.On Day 14,there was a small amount of CNV in Group C,while a larger number of centripetal growing CNV occurred in Group A and Group B,partially invading the central region of the cornea.The CNV of Group D was coarse and numerous and all corneas were seen to invade the central regions with CNV,6 corneas occurred by ulcers,and 2 by perforations.Four ulcers appear in Group A,and none in Group B and C.On Day 28,the CNV in Group D is the thickest and densest.5 corneal ulcers appeared in Group A,while 8 ulcers and 3 corneas with perforation in Group D.2.HE staining:HE staining slices showd that the epithelial defecting,inflammatory cell infiltrating and CNV growing,obviously in Group D.3.VEGF:On Day 7,14,28,the VEGF concentration decreased in Group A,B,C compared with Group D(P<0.01);There were significant differences among Group A,B,C(P<0.01),except Group B and C in Day 28.(P>0.05).4.the density of the CNV : On Day 7,14,28,the CNV areas decreased in Group A,B,C compared with Group D(P<0.01).There was no significant difference among Group A,B,C(P>0.05).5.Confocal microscopy: on Day 3,all of the corneas in four groups had epithelial loss,epithelial and stromal edema.We may not see any inflammatory cells,immune cells and CNV appeared in central stromal layers.On Day 7,the edema of the stromal layers was still obvious in four groups.A small amount of inflammatory cells infiltrated in stroma,and in Group D infiltrated more.The CNV in the four groups had been grown into the stromal layers,while the corneals of Group D had more blood vessels and branches than other groups.No CNV could be seen in the central region of the four groups.On Day 14,the edema of the stromal layers in the four groups was alleviated,the fibers were still confusing,and the CNV had been grown in a large amount.The CNV in the central region had been seen in some eyes of Group A,B,C and all eyes of Group D.The vascular density of Group D was highest.There was no significant difference of the vessels in Group A,B and C.The inflammatory cells increased in four groups,especially in Group D.4 corneas in Group A and 6corneas in Group D had ulcers.On Day 28,scars appeared in the stromal layers,and inflammatory cells were reduced in four groups.Only some corneas of Group A,B and C showed sparse CNV in the central regions,while showed thick and dense CNV in Group D.6.Inflammatory cell density: on Day 7,no statistical difference appeared in four groups(P>0.05).On Day 14,there was a statistically significant difference in four groups(P<0.001),and statistical differences appeared between any two treatment groups(P<0.01).On Day 28,statistical differences appeared in four groups(P<0.01),while no significant difference between Group A,B and C(P>0.05).Conclusion: Low concentrations of KH902 have the ability to inhibit neovascularization induced by alkali burn on rabbits.