Conjunctival changes induced by prostaglandin analogues and timolol maleate: a histomorphometric study.
OBJECTIVE
To compare histological changes induced by antiglaucoma medications in the rabbit conjunctiva.


METHODS
Fifty New Zealand rabbits were divided in 5 groups of 10 animals. The left eyes were treated daily with one drop of bimatoprost 0.03%, travoprost 0.004%, latanoprost 0.005%, timolol maleate 0.5% or artificial tears containing benzalkonium chloride (BAK) for 30 days. The right eyes served as controls. Superior limbic conjunctival biopsies were performed at the 8th and 30th day in 5 rabbits of each group. The conjunctiva was fixed with 10% formaldehyde, followed by HE and PAS staining. Morphohistometric quantitative analyses were performed to evaluate the following parameters: inflammatory infiltrate, epithelial thickness, number of goblet cells, diameter and number of blood vessels.


RESULTS
At the 8th and 30th posttreatment days, all groups, except one that received artificial tears, exhibited a diffuse inflammatory infiltrate, composed by lymphocytes and neutrophils, which was denser in the timolol group than in the prostaglandin (PG) analogues groups. At the 30th day, the timolol group also showed an increased subepithelial collagen density and a significant increase in epithelial thickness (p=0.0035). The goblet cell density was significantly increased at the 8th day in the group treated with travoprost (p=0.0006), and at the 30th day in those treated with bimatoprost (p=0.0021) and latanoprost (p=0.009).


CONCLUSIONS
Although a moderate, diffuse inflammatory infiltrate was observed in PG-treated eyes, no changes in conjunctival epithelial thickness or subconjunctival collagen density were observed with these medications, suggesting that these drugs induce fewer changes than timolol maleate in the rabbit conjunctiva.
Russ
Heloisa Helena Abil
HH
Universidade de São Paulo, São Paulo, SP, Brazil. heloisaruss@onda.com.br
Costa
Vital Paulino
VP
Ferreira
Fabiano Montiani
FM
Valgas
Sílvia Regina
SR
Correa Neto
Mario Adolfo
MA
Strobel
Eduardo von Linsingen
Ev
Truppel
Jessé Henrique
JH
D000577:Amides / Q000008:administration & dosage / Q000009:adverse effects; D000704:Analysis of Variance; D000818:Animals; D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000009:adverse effects*; D001548:Benzalkonium Compounds / Q000008:administration & dosage / Q000009:adverse effects; D000069580:Bimatoprost; D001706:Biopsy; D003008:Cloprostenol / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives; D003228:Conjunctiva / Q000187:drug effects* / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D020397:Goblet Cells / Q000187:drug effects / Q000473:pathology; D000077338:Latanoprost; D009883:Ophthalmic Solutions / Q000008:administration & dosage*; D011461:Prostaglandins F, Synthetic / Q000008:administration & dosage / Q000009:adverse effects; D011465:Prostaglandins, Synthetic / Q000008:administration & dosage / Q000009:adverse effects*; D011817:Rabbits; D013194:Staining and Labeling; D013997:Time Factors; D013999:Timolol / Q000008:administration & dosage / Q000009:adverse effects*; D000069557:Travoprost
D000577:Amides; D000959:Antihypertensive Agents; D001548:Benzalkonium Compounds; D009883:Ophthalmic Solutions; D011461:Prostaglandins F, Synthetic; D011465:Prostaglandins, Synthetic; D003008:Cloprostenol; D000077338:Latanoprost; D013999:Timolol; D000069580:Bimatoprost; D000069557:Travoprost