Efficacy and safety of modified chitosan eye drops in the treatment of Candida albicanskeratitis in rabbits

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.