Conjunctiva-Associated Lymphoid Tissue (CALT) Reactions to Antiglaucoma Prostaglandins with or without BAK-Preservative in Rabbit Acute Toxicity Study

• Published in: PloS one Vol. 7; no. 3; p. e33913
• Main Authors: Liang, Hong, Baudouin, Christophe, Labbe, Antoine, Riancho, Luisa, Brignole-Baudouin, Françoise
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 19.03.2012; Public Library of Science (PLoS)
• Subjects: Acute toxicity; Analogs; Analysis; Animals; Apoptosis; Benzalkonium chloride; Benzalkonium Compounds - adverse effects; Benzalkonium Compounds - pharmacology; Beta blockers; Biocompatibility; Biology; CD45 antigen; Cellular biology; Chloride; Chlorides; Confocal microscopy; Conjunctiva; Conjunctivitis - chemically induced; Conjunctivitis - metabolism; Conjunctivitis - pathology; Cytokines; Dose-Response Relationship, Drug; Drugs; Eye; Eye (anatomy); Glaucoma; Glaucoma - drug therapy; Immune response; Immune system; Immunity; Immunology; In vivo methods and tests; Infiltration; Inflammation; Leukocyte Common Antigens - metabolism; Life Sciences; Lymphoid tissue; Lymphoid Tissue - metabolism; Lymphoid Tissue - pathology; Male; Microscopy; Mucin 5AC - metabolism; Ophthalmic agents; Ophthalmic Solutions - adverse effects; Ophthalmic Solutions - pharmacology; Preservatives; Preservatives, Pharmaceutical - adverse effects; Preservatives, Pharmaceutical - pharmacology; Prostaglandins; Prostaglandins - adverse effects; Prostaglandins - pharmacology; Rabbits; Systemic diseases; Toxicity; Tumor necrosis factor-TNF; Vaccines; Veterinary Science; France
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0033913

Conjunctiva-associated lymphoid tissue (CALT) is closely associated with ocular surface immunity. This study investigated the effects of antiglaucoma prostaglandin analogs with or without benzalkonium chloride (BAK) preservative on organized CALT using an acute toxic model. A total of 48 albino rabbits were used and seven groups of treatments were constituted. Solutions (50 µl) of PBS, 0.02%BAK, (0.02%BAK+)latanoprost, (0.015%BAK+)travoprost, (0.005%BAK+)bimatoprost, (BAK-free)travoprost preserved with the SofZia® system or (BAK-free)tafluprost were instilled 15 times at 5-min intervals in both eyes. CALT changes were analyzed using in vivo confocal microscopy (IVCM), immunohistology in cryosections for detecting MUC-5AC+ mucocytes and CD45+ hematopoietic cells. Antiglaucoma eye drops stimulated inflammatory cell infiltration in the CALT, and seemed to be primarily related to the concentration of their BAK content. The CALT reaction after instillation of BAK-containing eye drops was characterized by inflammatory cell infiltration in the dome and intrafollicular layers and by cell circulation inside the lymph vessels. CD45 was strongly expressed in the CALT after instillation of all BAK-containing solutions at 4 h and decreased at 24 h. The number of MUC-5AC+ mucocytes around the CALT structure decreased dramatically after instillation of BAK-containing solutions. This study showed for the first time the in vivo aspect of rabbit CALT after toxic stimuli, confirming the concentration-dependent toxic effects of BAK. IVCM-CALT analysis could be a pertinent tool in the future for understanding the immunotoxicologic challenges in the ocular surface and would provide useful criteria for evaluating newly developed eye drops.