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Investigation of hydration processes of the equine hoof via nuclear magnetic resonance microscopy

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  • 1 Laboratory of Animal Physiology and Functional Anatomy, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan.
  • | 2 Clinical Science and Pathobiology Division, Equine Research Institute, Japan Racing Association, 321-4, Tokami-cho, Utsunomiya, Tochigi 320-0856, Japan.
  • | 3 Laboratory of Animal Physiology and Functional Anatomy, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan.
  • | 4 Laboratory of Animal Physiology and Functional Anatomy, Graduate School of Agriculture, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan.
  • | 5 Clinical Science and Pathobiology Division, Equine Research Institute, Japan Racing Association, 321-4, Tokami-cho, Utsunomiya, Tochigi 320-0856, Japan.
  • | 6 Clinical Science and Pathobiology Division, Equine Research Institute, Japan Racing Association, 321-4, Tokami-cho, Utsunomiya, Tochigi 320-0856, Japan.

Abstract

Objective—To examine the distribution of water in hoof wall specimens of horses via nuclear magnetic resonance (NMR) microscopy and determine changes in water distribution during hydration.

Sample—4 hoof wall specimens (2 obtained from the dorsum and 1 each obtained from the lateral quarter and lateral heel regions) of the stratum medium of healthy hooves of 1 horse.

Procedures—Equine hoof wall specimens were examined via NMR microscopy. Proton density–weighted 3-D images were acquired. Changes during water absorption were assessed on sequential images.

Results—The inner zone of the stratum medium had higher signals than did the outer zone. Areas of high signal intensity were evident in transverse images; these corresponded to the distribution of horn tubules. During water absorption, the increase in signal intensity started at the bottom of a specimen and extended to the upper region; it maintained the localization pattern observed before hydration. The relationship between the local maximal signals in areas corresponding to the horn tubules and minimal signal intensities in areas corresponding to the intertubular horn was similar and maintained approximately a linear distribution.

Conclusions and Clinical Relevance—Based on the premise that signal intensity reflects water content, hydration in the equine hoof wall during water absorption occurred concurrently in the tubules and intertubular horn, and there was maintenance of the original water gradients. This technique can be applied for the assessment of pathophysiologic changes in the hoof wall on the basis of its hydration properties.

Abstract

Objective—To examine the distribution of water in hoof wall specimens of horses via nuclear magnetic resonance (NMR) microscopy and determine changes in water distribution during hydration.

Sample—4 hoof wall specimens (2 obtained from the dorsum and 1 each obtained from the lateral quarter and lateral heel regions) of the stratum medium of healthy hooves of 1 horse.

Procedures—Equine hoof wall specimens were examined via NMR microscopy. Proton density–weighted 3-D images were acquired. Changes during water absorption were assessed on sequential images.

Results—The inner zone of the stratum medium had higher signals than did the outer zone. Areas of high signal intensity were evident in transverse images; these corresponded to the distribution of horn tubules. During water absorption, the increase in signal intensity started at the bottom of a specimen and extended to the upper region; it maintained the localization pattern observed before hydration. The relationship between the local maximal signals in areas corresponding to the horn tubules and minimal signal intensities in areas corresponding to the intertubular horn was similar and maintained approximately a linear distribution.

Conclusions and Clinical Relevance—Based on the premise that signal intensity reflects water content, hydration in the equine hoof wall during water absorption occurred concurrently in the tubules and intertubular horn, and there was maintenance of the original water gradients. This technique can be applied for the assessment of pathophysiologic changes in the hoof wall on the basis of its hydration properties.

Contributor Notes

Dr. Yoshihara's present address is Racehorse Hospital, Ritto Training Center, Japan Racing Association, 1028, Misono, Rittoshi, Shiga, 520-3005, Japan.

Dr. Wada's present address is Equine Department of Veterinary Section, Japan Racing Association, 11-1, Roppongi-6-chome, Minato-ku, Tokyo, 106-8401, Japan.

Supported in part by a grant from the Japan Racing Association.

Presented in abstract form at the Annual Meeting of the Japanese Society of Equine Science, Tokyo, November 2009.

Address correspondence to Dr. Sugimoto (sugimoto@kais.kyoto-u.ac.jp).