Comparison between two cyclooxygenase inhibitors in an experimental dry eye model in albino rabbits

Abstract

Dry eye syndrome, or keratoconjunctivitis sicca (KCS), is one of the most frequent ocular disorders. It may lead to progressive corneal opacification and blindness (1). Secretory, neuronal and mechanical processes that regulate the production and mixing of tear film constituents are functionally integrated (2). The ageing process, hormonal, environmental, iatrogenic, pharmacological and pathogenic factors may disrupt the tear film with subsequent ocular surface inflammation (3). The hyperosmolar tear film stimulates the production of mitogen-activated protein kinase (4). This initiates a cascade of protein phosphorylation involving other kinases and nuclear transcription factors which stimulate the proinflammatory cytokines and chemokines in tear fluid and conjunctival epithelium in KCS (5). The purpose of this study was to compare the topical anti-inflammatory effects of the nonselective cyclooxygenase (COX) inhibitor, ketorolac, with the selective COX-2 inhibitor, nimesulide, in an animal model of dry eye in albino rabbits. All animals were examined by the Schirmer test, tear break-up time (TBUT) and fluorescein corneal staining test. Dry eye model showed significant reduction in tear volume, TBUT, corneal staining and histopathological signs of dryness and inflammation. On treating dry eye model with nimesulide 0.1% eye drops and ketorolac 0.5% eye drops, there were improvements in Schirmer test values, TBUT and fluorescein corneal staining and histopathologically reduced inflammatory reaction, with signs of healing and regeneration. Both nimesulide and ketorolac ameliorate atropine sulphate induced dry eye in albino rabbits. The use of selective COX-2 inhibitor, nimesulide, is preferred to avoid local and systemic side effects which may occur with the use of the nonselective COX inhibitor, ketorolac.

Comparação entre dois protocolos de tratamento de ceratoconjuntivite seca experimentalmente induzida em coelhos

“…Para a indução da CCS, nos coelhos, adotou-se um modelo baseado em estudos previamente publicados (Burgalassi et al, 1999;El-Shazly et al, 2008) Uma semana após a indução da CCS, os animais foram tratados durante 12 semanas da seguinte maneira: grupo C (n=5) controle (uma gota de placebo -solução de NaCl 0,9%) tópica, duas vezes ao dia, em ambos os olhos; grupo AAP (n=5): formulação oftálmica com 3,5mL de álcool polivinílico 1,4% + 3,5mL de acetilcisteína 10% + 1mL de pilocarpina 1% (Laboratório Ophthalmos), 1 gota, duas vezes ao dia, por via tópica, em ambos os olhos; grupo L (n=5): colírio à base de óleo de semente de linhaça puro (Laboratório Ophthalmos), uma gota, duas vezes ao dia, por via tópica, em ambos os olhos.…”

Comparison of 1% cyclosporine eye drops in olive oil and in linseed oil to treat experimentally-induced keratoconjunctivitis sicca in rabbits

“…Atropine is a competitive antagonist of the muscarinic acetylcholine receptors. As the ocular surface and main lacrimal gland are innervated by parasympathetic fibers of the seventh cranial nerve; the use of atropine is known to cause decreased tear secretion and con sequent inflammation in a similar way to dry eye syndrome (20)(21)(22) . Eye drops were administered until the diagnosis of KCS (7 days to induce KCS in all rabbits) was confirmed by a Schirmer tear test 1 (STT; Teste de Schirmer®; Ophthalmos Laboratory) result of ≤5 mm/min and/or ≤10 seconds tear-film break-up time (TBUT) (23,24) and throughout the treat ment period (12 weeks) for KCS maintenance.…”

“…The induction model of KCS in rabbits was based on previously published studies that used 1% atropine sulfate eye drops three times daily (15,16,(20)(21)(22) . Atropine is a competitive antagonist of the muscarinic acetylcholine receptors.…”

Comparative evaluation of efficacy and safety of Carboxymethylcellulose either alone or in combination with Non-Steroidal Anti-inflammatory drug in the treatment of Dry eye in a Tertiary care Teaching Hospital

“…4,5 Dry eye disorder results in a diminished quality of life for those affected. In a study, it was found that patients with dry eye were signifi cantly more likely to report ABSTRACT Background: Dry eye produces discomfort and reduced vision.…”

“…2,3 As infl ammation is a key component in the pathogenesis of dry eye, non-steroidal anti-infl ammatory drugs (NSAIDs) have recently been evaluated in dry eye clinical trials and in animal models. 4,5 Dry eye disorder results in a diminished quality of life for those affected. In a study, it was found that patients with dry eye were signifi cantly more likely to report diffi culty with daily tasks than those without dry eye.…”