Effect of systemic administration of phytosterol on lacrimal quality of dogs

Fernanda Gosuen Gonçalves Dias,Tais Harumi De Castro Sasahara,Larissa Fernandes Magalhães,Brenda Martins Cristino,Lucas De Freitas Pereira,Ricardo Andrade Furtado,Adriana Torrecilhas Jorge,Claudianara Ávila Silva,Cristiane Dos Santos Honsho

doi:10.14393/bj-v35n4a2019-41782

Fernanda Gosuen Gonçalves Dias, Tais Harumi De Castro Sasahara + Show 7 more

Open Access

https://doi.org/10.14393/bj-v35n4a2019-41782

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Journal: Bioscience Journal	Publication Date: Jun 12, 2019
Citations: 1	License type: cc-by

Affiliation: Universidade de Franca

Abstract

The tear lipid layer (oily outer layer) reduces evaporation and prevents tear overflow. In dogs, reductions in the lipid components of this layer (cholesterol, triglycerides and phospholipids) can cause eye serious diseases. In this way, the tear crystallization test analyzes the lacrimal quality, however, it is less used in veterinary. As phytosterol reduces blood cholesterol, the objective of this study was to investigate, through the tear crystallization test, whether the systemic administration of this drug influences the lacrimal quality of healthy dogs and, in addition, to verify differences in the interpretation of the ophthalmic test between different evaluators. Eight beagles, healthy, of both sexes, young and adults, without clinical ophthalmic signs apparent were selected. Basal lacrimal samples (D0) were collected from the right and left eye of all animals with glass capillary tube and arranged on a glass slide for scanning the images and subsequent microscopic analysis. Subsequently, all were medicated with the phytosterol (Collestra® 650 mg: 1 capsule, orally, every 12 hours, for 15 days). After seven (D7) and fifteen (D15) days of this systemic administration, the tear crystallization test in both eyes of all dogs was again performed for statistical comparison with the baseline results. The photographs of the slides were classified by four evaluators (AV1 and AV2 with professional experience in ophthalmology and AV3 and AV4 without previous professional experience in ophthalmology), following standards established by Rolando (1984). The results were statistically verified by analysis of simple variance (ANOVA One-Way). There was no statistical difference in the tear crystallization test between the established periods and in relation to the different ophthalmic test evaluators (p≤0.05). Although phytosterols reduce blood cholesterol levels, it was observed in the present study that these drugs when administered systemically did not interfere in the tear lipid layer and, consequently, in the lacrimal quality of healthy dogs, and may be prescribed as lipid-lowering agents for patients with ocular diseases, especially the lacrimal ones.

Highlights

The lipid layer of the tear is composed of cholesterol, triglycerides and phospholipids (TORRICELLI; WILSON, 2014; HSU et al, 2015) which decrease evaporation, increase break time and prevent tear leakage (BRON et al, 2004; DAVIDSON; KUONEN, 2004)
As phytosterol reduces blood cholesterol, the objective of this study was to evaluate, through the tear crystallization test, whether the systemic administration of this drug influences the lacrimal quality of healthy dogs and, in addition, to verify differences in the interpretation of the ophthalmic test between different evaluators
In cases where p≤0.05, the means were compared by Tukey test, with the calculation of the minimum significant difference to α = 0.05, using the Graphpad Prism Software 6.0® Program. It was observed no statistical difference in the tear crystallization test for the different moments of analysis (D0, D7 and D15) (Figure 2)

Summary

Introduction

The lipid layer of the tear is composed of cholesterol, triglycerides and phospholipids (TORRICELLI; WILSON, 2014; HSU et al, 2015) which decrease evaporation, increase break time and prevent tear leakage (BRON et al, 2004; DAVIDSON; KUONEN, 2004). The lipid reduction at this layer contributes to the ocular disorders (OFRI et al, 2007). In this sense, the test of tear crystallization (fern test) is based on the formation of crystals, classified microscopically in patterns, according to the presence and amount of branches in the shape of fern leaves (MURUBE, 2004; FELDBERG et al, 2008). In the pattern I, the crystallization originates multi-branched trees, with no empty spaces between the branches, characterizing better lacrimal quality when compared to the other standards. In pattern III, the spaces between the branches are large and rare and the pattern IV is characterized by clumps of crystals that seldom form branches (ROLANDO, 1984)

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