Feline uveitis: Therapeutic effect of melatonin

Abstract

Acute or chronic uveitis is a common ophthalmic disorder that constitutes one of the main causes of irreversible blindness in domestic cats. Uveitis affects primarily the uveal tract, but other ocular critical structures can also be affected. In addition, inflammation of the posterior segment (choroid and retina) of the eye may provoke retinal detachment and degeneration, with consequent blindness. At present, treatment of cats with uveitis generally involves administration of corticosteroids, which is directed toward reduction of pain and lesions in ocular tissues. However, the immunosuppressive effect of corticosteroids may contribute to the development of the systemic disease, and their chronic use could result in corticosteroid-induced glaucoma. A novel method for experimental induction of uveitis in cats would greatly facilitate the understanding of the cellular events involved in ocular inflammation as well as the development of new treatment strategies. In this chapter, we will summarize recent investigations showing that a single intravitreal injection of bacterial lipopolysaccharide (LPS) in cat eyes induces clinical, biochemical, functional, and histological changes that are consistent with the main features of naturally occurring feline uveitis, and that melatonin prevents clinical, biochemical, histological, ultrastructural, and functional consequences of experimental uveitis in cats.