Abstract
Purpose: :
To compare histological changes induced by antiglaucoma fixed combinations in the rabbit conjunctiva.
Methods: :
30 New Zealand female rabbits with similar age and weight were divided in 3 groups of 10 animals each. The right eyes were treated with one daily drop of timolol maleate 0.5% associated with bimatoprost 0.03% (Ganfort® - Allergan), travoprost 0.004% (Duo-Travatan® - Alcon) and latanoprost 0.005% (Xalacom® - PharmaciaPfizer) for 30 days. The left eyes served as controls and did not receive medication. Then all rabbits were euthanized, the eyes were enucleated and immediately fixed with 10% formaldehyde for 24 hours, stained with HE and PAS and then evaluated by light microscopy. Morphohistometric analyses were made using the Image Pro-Plus 4.5 software. The parameters evaluated were: conjunctival numbers of inflammatory cells and goblet cells. One-way ANOVA with a significance level of 5% followed by Tukey-Kramer post hoc tests were used to analyze numerical variables.
Results: :
At the 30th day post treatment, all groups exhibited a rather diffuse inflammatory infiltrate, composed by lymphocytes and neutrophils. A baseline low level infiltration, consisting of localized clusters cells was observed in the subepithelial connective tissue of most of the control eyes. There was, however, no significant change in the inflammatory cell numbers comparing all groups studied. A significant increase in number of goblet cells in all treated eyes compared to control eyes (P=0.002) was seen. The goblet cell density significantly increased (P=0.012) in eyes treated with bimatoprost + timolol maleate compared to latanoprost + timolol maleate. There was no significantly difference between bimatoprost + timolol maleate and travoprost + timolol maleate, neither between latanoprost + timolol maleate and travoprost + timolol maleate.
Conclusions: :
A change from focal to diffuse inflammatory cell infiltrate was seen in all treated eyes. An increase in goblet cell numbers was seen with the use of all fixed combinations of timolol maleate + prostaglandin analogues compared to control, not-treated eyes. Bimatoprost + timolol maleate significantly increased goblet cell numbers more than the others combinations.
Keywords: drug toxicity/drug effects • conjunctiva • pathology: experimental