ABSTRACT
Objective:To evaluate the clinical efficacy and safety of modified chitosan eye drops on rabbit Candida albicans keratitis model.Methods:Ten healthy female New Zealand rabbits were used to establish the superficial Candida albicans keratitis model by the corneal surface lens method in the right eye.Slit lamp microscopy and corneal scraping and microscopic examination were performed to preliminarily determine whether the keratitis model has been successfully established, the rabbits were then randomly divided into a model group and a modified chitosan group by the random number table method.The successfully established rabbit models which were determined by fungal culture results were retained.Five normal rabbits receiving no intervention served as a normal control group.The experimental eyes in the normal control and modified chitosan groups were treated with modified chitosan eye drops, Six times a day for one week, and subsequently four times a day for one week.No treatment was administered to the model group.The changes of corneal lesions and ocular surfaces were examined by slit lamp microscopy every day.At 1, 7, 14, 21 and 28 days after modeling, the eye condition and corneal clinical scores was assessed by slit lamp microscopy.The corneal conditions in each group was observed for two weeks after drug withdrawal.Results:The corneal scraping and microscopic examination results of eight rabbits models showed that the fungal hyphae and spores were positive.The fungal culture results showed that the separated pathogen was Candida albicans.The success rate of modeling was 80%(8/10). The clinical scores in the model group at 7, 14 and 21 days after modeling were 14.50±0.58, 6.25±0.50 and 2.50±0.58, respectively, and were significantly higher than 7.25±1.26, 2.75±0.50 and 1.25±0.50 in the modified chitosan group (all at P<0.05). In the model group, corneal edema was significantly aggravated, and the central white ulcer area was enlarged within seven days after modeling.Between 7 and 28 days after modeling, the corneal ulcer was gradually healed, while the central corneal scar and neovascularization were remained.The average healing time was (24.5±2.6)days.In the modified chitosan group, the corneal infiltration was significantly alleviated within seven days after modeling, and the fungal hyphae and spores of corneal scraping were negative on the 14th day after modeling.The average healing time in the modified chitosan group was (13.5±1.3)days, which was significantly shorter than that in the the model group (P<0.01). No recurrence of keratitis was observed in the modified chitosan group after two weeks of drug withdrawal.The cure rate was 100%.In the normal control group, the conjunctival hyperemia, corneal edema, and lesions were not observed during topical administration.Conclusion:The treatment with modified chitosan eye drop is effective in a rabbit superficial Candida albicans keratitis model, and have no obvious toxic effects on ocular tissues.
ABSTRACT
Objective To investigate the inhibitory effect of bromfenac sodium hydrate ophthalmic solution on corneal neovascularization (CNV) induced by alkali burn.Methods A total of 192 specific pathogen free (SPF) degree adult male Sprague-Dawley (SD) rats were used in this study.One hundred and seventy-two rats were chosen to establish CNV model with alkali burn in the right eyes.Following alkali burn,rats were randomly divided into CNV group,model control group,bromfenac sodium group and fluorometholone group,with 43 rats (43 eyes) in each group.Another 20 rats (40 eyes) served as normal control group.One day after modeling,the model control group,bromfenac sodium group and fluorometholone group received phosphate buffer saline (PBS),bromfenac sodium hydrate ophthalmic solution and 0.1％ fluorometholone eye drops,respectively.The state of cornea and anterior chamber and the growth of CNV of rats in each group were observed by slit-lamp microscope every day after modeling.At 1,3,7,14,21 and 28 days after modeling,the anterior segment photos of the experimental eyes were captured,and the percent of cornea areas covered by CNV was calculated.At 7,14 and 28 days after modeling,the eye tissue sections were stained with hematoxylin and eosin staining and immunohistochemistry staining to evaluate the expressions of CD45 and VEGF-A.Real-time quantitative PCR and enzyme-linked immunosorbent assay (ELISA)were used to detect the expression of COX-2 and VEGF mRNA and protein level.The use and care of the animals complied with the Statement of the Association for Research in Vision and Ophthalmology(ARVO).Results Each model group showed corneal edema and opacification 1 day after modeling.The corneal edema was aggravated 7 days after modeling.On the 14th day after modeling,the degree of corneal opacity and edema decreased gradually.On the 28th day after modeling,leucoma was observed in CNV group and model control group,and nebula was observed in bromfenac sodium group and fluorometholone group.At 7,14,21 and 28 days after modeling,the percentages of CNV areas in bromfenac sodium group and fluorometholone group were significantly lower than those in CNV group and model control group (all at P＜0.05).No significant difference was found in the percentage of CNV areas between bromfenac sodium group and fluorometholone group at various time points (all at P＞0.05).On the 7th day after modeling,the thinning of corneal epithelial layer,edema and arrangement disorder of stroma layer were observed,and the expression of VEGF-A was positive in all model groups;a small amount of CD45 positive inflammatory cell infiltrations were observed in CNV group and model control group.On the 14th and 28th day after modeling,CNV was seen in the center of cornea in CNV group and model control group;the epithelial keratosis and reduction of corneal edema were seen in each group,and no inflammatory cell infiltration was observed in each group.On the 7th day after modeling,the expressions of COX-2 and VEGF mRNA in CNV group and model control group were significantly higher than those in normal control group,bromfenac sodium group and fluorometholone group (all at P ＜ 0.05),the expressions of COX-2 and VEGF protein in bromfenac sodium group were significantly lower than those in CNV group (all at P＜0.05).The corneal peroration rate in model control group and bromfenac sodium group was 10％ (1 case in 10 rats).The corneal perforation rate in fluorometholone group was 30％ (3 cases in 10 rats).In each model group,10％ to 30％ rats had hyphema.Conclusions Bromfenac sodium hydrate ophthalmic solution can inhibit the formation and growth of CNV after alkali burn in rats.This effect may be mediated by regulating COX-2 expression,reducing inflammation and inhibiting VEGF production.