Effects of the Ottonia martiana Miq. (Piperaceae) extract on dog's ocular surface

Estudaram-se os efeitos do extrato das folhas de Ottonia martiana sobre a superfície ocular de cães hígidos da raça Beagle. Compuseram-se três grupos de tratamento (n=15): grupo controle (GC), grupo proximetacaína (GP) e grupo Ottonia (GO), tratados, respectivamente, com solução fisiológica, colírio de cloridrato de proximetacaína a 0,5% e extrato de O. martiana. Após avaliação oftálmica inicial, os tratamentos foram realizados no tempo 0 (T0) e decorridos 3min (T3). Avaliaram-se a sensibilidade axial da córnea por estesiometria (T5 e T10) e a produção lacrimal e a pressão ocular (T10). Realizaram-se a biomicroscopia com lâmpada em fenda (T10 e T20), e o teste do tingimento pela fluoresceína (T20). Relativamente ao teste de Schirmer, observou-se diminuição nos cães do GP. Houve alteração clínica somente nos do GP, em que 13 animais apresentaram hiperemia conjuntival. Relativamente à estesiometria, houve diminuição da sensibilidade corneal nos animais do GP e do GO. Admite-se que o extrato de O. martiana age diminuindo a sensibilidade corneal em cães e que sua utilização não diminui a produção lacrimal, tampouco causa alterações clínicas oftálmicas.

Abstract (english)

The anesthetics effects of aqueous extract of Ottonia martiana leaves were studied on the ocular surface of healthy beagle dogs. The dogs were divided in three groups (n=15): control group (CG), proxymetacaine group (PG) and Ottonia group (OG), which were treated with 0.9% saline, 0.5% proxymetacaine hydrochloride ophthalmic solution and O. martiana extract respectively. An oftalmic evaluation was performed before the treatments. Eye drops were instilled at time 0 (T0) and 3 minutes later (T3). Axial corneal sensitivity was evaluated by esthesiometry 5 and 10 minutes after T0. Tear production and intraocular pressure were evaluated 10 minutes after T0. Slit lamp biomicroscopy was performed 10 and 20 minutes after T0 and the eyes were stained with fluorescein 20 minutes after T0. The STT was reduced in PG. Conjunctival hyperemia was observed in 13 animals from PG and constituted the only ocular alteration observed during the study. Esthesiometry revealed a decreased corneal sensitivity for PG and OG. Those results show that the O. martiana extract acts reducing corneal sensitivity in dogs. Moreover, its use does not decrease the tear production and does not cause any clinical ophthalmic alteration.