Abstract
Purpose: :
To compare immunohistochemical changes induced by antiglaucoma fixed combination therapies.
Methods: :
30 New Zealand rabbits were divided in 3 groups of 10 animals.The left 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 right eyes served as controls. All rabbits were euthanized, enucleated and fixed with 10% formaldehyde for 24 hours. The material were processed for immunohistochemistry using anti-factor VIII and anti-actin antibodies and then evaluated by light microscopy. IHC images were analyzed by the Image Pro-Plus 4.5 software. Parameters evaluated were: number of reactive blood vessels to factor VIII and qualitative evaluation of fibroblasts labeled for actin.The scores for fibrosis were classified from minimum to severe. One-way ANOVA with significance level of 5% followed by Tukey-Kramer post hoc tests were used to analyze numerical variables (factor VIII). The evaluation of the ordinal categorical variables (actin-labelling) was performed by means of analysis descriptive statistics and Fischer Exact Test.
Results: :
A significant increase in factor VIII-labeled blood vessels was observed in eyes treated with latanoprost+timolol (5.56 ± 1.6; P=0.004) and bimatoprost+timolol (4.5 ± 1.6; P=0.046).The increase was significant higher in eyes latanoprost+timolol compared to travaprost+timolol (P=0.018).Conversely in eyes treated with travoprost+timolol a trend towards a higher intensity of actin-labeling was seen , followed by bimatoprost+timolol and lastly by latanoprost+timolol.
Conclusions: :
All fixed combinations of prostaglandin analogues and timolol caused a certain degree of conjunctival inflammatory response, either by provoking a degree of subendotelial of fibrosis or an increase in numbers of reactive blood vessels. Eyes treated with latanoprost+timolol showed a greater number of reactive blood vessels. The degree of fibrosis was more intense in eyes treated with the association of travoprost+timolol.
Keywords: conjunctiva • drug toxicity/drug effects • pathology: experimental