Use of external nasal strip influences alveolar cell population of horses after exercise

T.M Oliveira,W.R Fernandes,P.M Bogossian,A.R Hilgert

doi:10.1590/1678-4162-12325

Abstract

ABSTRACT The nasal strip is widely used in horses during exercise, but effects of using a nasal strip are controversial and little is known about its effect on horses undergoing endurance events. The aim of this study was to determine whether the use of nasal strips influences alveolar cell population assessed by bronchoalveolar lavage (BAL), tidal volume, and nasal airflow rate. Six Arabian horses were subjected to two low intensity tests on a treadmill, with and without application of a commercial external nasal strip. Tidal volumes and airflow rates were measured during the test; two hours after the test, BAL was performed to assess cytology of pulmonary secretions. The lavage fluid showed increased neutrophil count after exercise in animals with the nasal strip (P<0.05). This suggests that turbulence of airflow through the nasal cavity may have diminished with nasal strip use, thus allowing larger particles to be deposited more distally in the respiratory system, inducing a more intense neutrophilic response. No differences in tidal volumes or airflow rates were observed between groups (with or without nasal strips) during the test (P>0.05). The use of nasal strips seems to influence alveolar cell population during and after exercise in horses after low intensity exercise tests. Further studies are needed to verify whether alveolar cell population is related to poor exercise performance in horses.

Highlights

Respiratory physiology is an active, challenging research area in equine sports science, as there is increasing evidence that maximal oxygen uptake is one of the most important factors limiting exercise performance in medium to long distance rides (Evans, 2007; Marlin, 2015)
The aim of this study was to determine whether the use of nasal strips influences alveolar cell population assessed by bronchoalveolar lavage (BAL), tidal volume, and nasal airflow rate
Samples of BAL were obtained from six horses, at rest and after exercise, with and without the nasal strip

Summary

Introduction

Respiratory physiology is an active, challenging research area in equine sports science, as there is increasing evidence that maximal oxygen uptake is one of the most important factors limiting exercise performance in medium to long distance rides (Evans, 2007; Marlin, 2015). There are many specific characteristics in horses that contribute to this phenomenon, such as very high blood flow in the lungs (Davie et al, 2017); exclusively nasal breathing; and respiratorylocomotor coupling (Art et al, 1990b; Butler et al, 1993). Increased airway resistance is probably an additional factor that limits oxygen uptake and increases transmural pressure, as it may increase breathing effort, especially during long rides (Ducharme et al, 1999)

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