Abstract
Purpose:
To evaluate clinical and histopathological safety of a new artificial tear, chondroitin sulfate + xanthan gum (CX) applied on ocular surface of New Zealand rabbits.
Methods:
The study was conducted under ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. Sixteen rabbits were assessed. 16 eyes received CX and 16 eyes received placebo. The instillation was scheduled every two hours between 7 and 19 hrs during 15 days. Clinical assessment was accomplished on days 0 (baseline), 1, 2, 4, 7, 10 and 15. Safety parameters: conjunctival hyperemia, chemosis, corneal surface integrity, conjunctival secretion, Rose Bengal and fluorescein staining. On days 0 and 15, fundoscopy was performed under pharmacological mydriasis. At day 16, all rabbits where sacrificed and enucleated. A blind histopathological study was executed and the tissues were examined in order to determine: cornea (changes in the epithelial thickness, basal membrane integrity, cellular changes), conjunctiva (presence of goblet cells, apoptosis, diskeratinization).
Results:
Thirty-two eyes were assessed. Both groups had no pathological findings in the posterior segment, ciliary injection or fundus in the study. Two cases present of conjunctival hyperemia in the CX group (day 2 and 4), less than 25% of total conjuntival area. Chemosis in both groups was observed during the study. The percentage cases of chemosis was greater in the placebo group than in the CX group. CX group had a higher percentage of secretion, although, hyaline/whitish/crystal conjunctival discharge was in CX group and placebo group had cases of yellow/ green discharge. Of all sample, only one eye had altered corneal surface, which belonged to CX group as a valuation day 1, presenting corneal stippling. Any groups showed uptake Rose Bengal dye on the corneal surface. Both study groups showed uptake of fluorescein dye in the corneal surface of the eye by evaluating the day 1 until the end of follow-up, all cases were stained with score 1. There were no statistically significant intergroup differences. In both groups no cytological toxicity changes were found
Conclusions:
The safety parameters evaluated in the study showed that the polimer combination in CX is clinical and histopathological safe and no toxic when is compared with placebo group and applied to the ocular surface of New Zealand rabbits.
Keywords: 486 cornea: tears/tear film/dry eye •
503 drug toxicity/drug effects •
480 cornea: basic science