Chemical Senses Advance Access originally published online on June 12, 2007
Chemical Senses 2007 32(6):633-639; doi:10.1093/chemse/bjm031
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"Green Odor" Inhalation Reduces the Skin-Barrier Disruption Induced by Chronic Restraint Stress in Rats: Physiological and Histological Examinations
1 Division of Integrative Physiology, Department of Functional, Morphological and Regulatory Science 2 Department of Fundamental Nursing 3 Division of Morphological Analysis, Department of Functional, Morphological and Regulatory Science, Tottori University Faculty of Medicine, Yonago, Tottori 683, Japan
Correspondence to be sent to: Tatsuo Watanabe, Division of Integrative Physiology, Department of Functional, Morphological and Regulatory Science, Tottori University Faculty of Medicine, Yonago, Tottori 683, Japan. e-mail: watanabe{at}grape.med.tottori-u.ac.jp
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Abstract |
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We investigated whether inhalation of green odor (a mixture of equal amounts of trans-2-hexenal and cis-3-hexenol) prevents the skin-barrier disruption induced by chronic restraint stress in rats. To this end, transepidermal water loss (TEWL) was measured as an index of the disruption of skin-barrier function, whereas light- and electron-microscope examinations were performed to observe histological changes in the skin of the stressed animals. In addition, the effects on TEWL induced by chronic administration of a glucocorticoid, dexamethasone (DEX), were examined. Chronic restraint stress (8 h per day for 14 days) increased TEWL (vehicle + stress group). This effect (and the chronic stress–induced increase in adrenal weight) was prevented in rats that inhaled green odor at the beginning of each day's restraint (2 h each day for 14 days; green odor + stress group). Electron-microscope studies revealed that rats in the green odor + stress group possessed sufficient intercorneocyte lipids to create an effective skin barrier, although these had apparently been decreased in the vehicle + stress group. Daily administration of DEX for 14 days increased TEWL. The present results suggest that chronic stress–induced disruption of the skin barrier in rats can be reduced or prevented by green odor (possibly at least in part through an inhibitory effect on the stress-induced activation of the hypothalamo-pituitary-adrenocortical axis).
Key words: adrenal gland, dexamethasone, hypothalamo-pituitary-adrenocortical axis, stratum corneum, transepidermal water loss
Accepted 5 April 2007