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The Scientific World Journal
Volume 2014, Article ID 378024, 8 pages
http://dx.doi.org/10.1155/2014/378024
Research Article

Dietary Hyaluronic Acid Migrates into the Skin of Rats

1R&D Division, Kewpie Corporation, 2-5-7 Sengawa Kewport, Sengawa, Chofu, Tokyo 182-0002, Japan
2ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., 2117 Muramatsu, Tokai-mura, Naka-gun, Ibaraki 319-1182, Japan

Received 8 May 2014; Revised 31 July 2014; Accepted 31 July 2014; Published 14 October 2014

Academic Editor: Enzo Berardesca

Copyright © 2014 Mariko Oe et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Hyaluronic acid is a constituent of the skin and helps to maintain hydration. The oral intake of hyaluronic acid increases water in the horny layer as demonstrated by human trials, but in vivo kinetics has not been shown. This study confirmed the absorption, migration, and excretion of 14C-labeled hyaluronic acid (14C-hyaluronic acid). 14C-hyaluronic acid was orally or intravenously administered to male SD rats aged 7 to 8 weeks. Plasma radioactivity after oral administration showed the highest level 8 hours after administration, and orally administered 14C-hyaluronic acid was found in the blood. Approximately 90% of 14C-hyaluronic acid was absorbed from the digestive tract and used as an energy source or a structural constituent of tissues based on tests of the urine, feces, expired air, and cadaver up to 168 hours (one week) after administration. The autoradiographic results suggested that radioactivity was distributed systematically and then reduced over time. The radioactivity was higher in the skin than in the blood at 24 and 96 hours after administration. The results show the possibility that orally administered hyaluronic acid migrated into the skin. No excessive accumulation was observed and more than 90% of the hyaluronic acid was excreted in expired air or urine.