Vet Med - Czech, 2019, 64(9):400-406 | DOI: 10.17221/162/2018-VETMED

The effect of moderate treadmill exercise on the resistive index of the medial long posterior ciliary artery in dogsOriginal Paper

Michela Pugliese^*,1, Monica Ragusa², Vito Biondi¹, Annamaria Passantino¹, Kai Zhang³, Francesco Macri¹

¹ Department of Veterinary Science, University of Messina, Polo Universitario Annunziata, Messina, Italy

² Department of Experimental and Clinical Medicine, University of Catanzaro, Viale Europa, Catanzaro, Italy

³ Department of Traditional Chinese Veterinary Medicine. Lanzhou Institute of Husbandry and Pharmaceutical Sciences of CAAS, Xiaoxihu, Qilihe District, Lanzhou city, Gansu province, People's Republic of China

The resistive index (RI) is an indirect measurement of arterial resistance by means of a ratio between the peak systolic and end diastolic velocities recorded with a spectral Doppler device, especially used to evaluate the vascular damage in ocular diseases such as glaucoma. Some ocular variables such as the intraocular pressure (IOP), the choroidal thickness, the axial length and the ocular blood flow may be influenced by physical exercise. The purpose of this study was to evaluate the influence of the exercise on the RI of the medial long posterior ciliary artery in dogs, and correlate the data obtained with the IOP values. Ten clinically healthy dogs were subjected to moderate physical exercise on a canine motorised treadmill at different speeds for 45 minutes. A colour Doppler examination was performed and the RI values were calculated for the medial long posterior ciliary artery at rest, immediately after the exercise, and after 60 minutes at the end of the exercise. At the same times, the IOP was recorded by applanation tonometry. The data were analysed by a two-way repeated ANOVA measurement in order to compare the RI and the IOP. Wilcoxon's test was applied for the post hoc comparison. Spearman's rank correlation for non-normal distribution was used to determine a relationship between the RI and the IOP. The at rest RI was 0.722 +/-0.022, IOP 12.38 +/3.21 mm Hg. A significant decrease in the RI was observed immediately after the exercise (0.697 +/-0.035) and during the passive recovery phase (0.682 +/-0.042). A significant decrease in the IOP (11+/3.39 mmHg) was recorded after 60 min of the passive recovery phase; at the end of the exercise, a slight decrease (12.29+/4.26 mm Hg) mm Hg was detected. During the test, a linear correlation between the RI and the IOP was observed. Our results suggest that exercise induces the modification of the ophthalmic blood flow in dogs, presumably related to the compensatory neuro-hormonal mechanisms.

Keywords: physical exercise, ocular variables, ocular blood flow

Published: September 30, 2019  Show citation