Study of Active Substances Involved in Skin Dysfunction Induced by Crowding Stress. I. Effect of Crowding and Isolation on Some Physiological Variables, Skin Function and Skin Blood Perfusion in Hairless Mice.

Abstract

Human skin functions not only as a barrier to retain the internal components and to protect internal organs from external stimulation or invasion, but also as a sensory organ to maintain homeostasis. In addition, it plays important roles in processes such as thermoregulation, antibody formation, vitamin D formation, lipid secretion, respiration, pigmentation and perception. [1][2][3][4][5][6] Stress disturbs the homeostasis, and may induce various disorders. For example, various kinds of physiological and psychological stress influence the hypothalamic-pituitaryadrenocortical axis, the hypothalamic-pituitary-gonadal axis, sympatho-adrenomedullary system and sympathetic nervous system, leading to changes in a number of organs. Stress has been implicated in hypertension, arteriosclerosis, diabetes mellitus, and other diseases in clinical and epidemiological studies.7) Skin function should also be influenced by stress, because it is primarily regulated by the autonomic nervous system and the endocrine system. This idea is supported by clinical reports showing that some skin disorders, including psoriasis and atopic dermatitis, are exacerbated by anxiety. 8)In addition, recent cutaneous biological studies have revealed that immobilization stress and/or overcrowding stress induced a decrease in lipogenesis in sebaceous glands, delay of skin barrier recovery and disruption of the skin barrier in rats, Syrian hamsters, and/or BALB/c mice.9-11) Barrier function and water retention are important cutaneous functions to maintain homeostasis. However, the relationship between stressful stimuli and skin dysfunction has not been established yet.Psychological stress activates the sympathetic nervous system, resulting in increases in the levels of glucocorticoids, catecholamines and angiotensin II in the circulating blood. Excess of glucocorticoid and angiotensin II can elevate blood pressure and excess of catecholamine increases cardiac output and peripheral resistance. Thus, stress induces acute hypertonic and chronic circulatory disorders. Hypertension causes hematogeneous disorder in the microvasculature. Therefore, concomitant reduced blood supply may contribute to peripheral ischemia. It is also suggested that mental stress induces transient endothelial dysfunction in humans. 12) Indeed, it is well recognized that psychological stress elevates blood pressure and that long-term stress causes dysfunction of the skin and various organs, such as ovary, kidney, thymus and adrenal glands.Recently, the laser Doppler perfusion-imaging technique has made it possible to map accurately changes of blood perfusion over a large area with good time resolution, and this method has been used to measure microcirculatory changes of the skin, mucosa, kidney and eye. 13,14) It has also been used for detecting abnormal blood flow in pathologically changed skin. 15)In this study, we have examined the relationship between blood perfusion and skin dysfunction mediated by catecholamines in animals exposed to a crowded environment. This approach ha...

Ingestion of bonito extract ameliorates peripheral blood flow in mice loaded from over crowding stress

“…In preliminary experiments, no significant differences between the blood flow measured on days 7 and 14 of overcrowded feeding were observed, indicating that the skin blood flow was already at the lowest attainable level by day 7. With regard to the degree of overcrowding, the area per animal of the present experiment was around 2800 cm 2 as compared to the 3800 cm 2 used in a previous report (10). These results indicate that the feeding in overcrowded conditions used in the pres-…”

“…There have been many reports that feeding in overcrowded conditions induces decreases in body weight gain (2,23), increases in blood catecholamines (4), and decreases in skin blood flow (10). In experiments conducted with hairless mice that were fed for 7 days in overcrowded conditions, the increases in blood catecholamines and the decreases in skin blood flow induced by overcrowded feeding depended on the length of loading and the degree of overcrowding (10). In the present experiment, CD2F1 mice were fed for 14 days in overcrowded conditions.…”

“…It has been reported that the levels of blood dopamine and arterial blood pressure are increased by mental stress in humans (28). Ishida et al (10) reported on the decrease in skin blood flow brought about by overcrowded conditions and considered it to have been brought about partly by the blood vessel-constricting action of catecholamines. The crowded-condition mice had increased levels of catecholamines in their circulating blood and a decreased rate of skin blood perfusion in comparison with the normal-condition mice, suggesting that the reduction of skin perfusion in the crowded-condition mice was induced mainly by the vasoconstrictive effects of stress-induced ca- Values are means ± SEM (n = 10).…”

Effects of Housing Conditions on the Development of Wet Skin Lesions in the NOA Mouse

“…The severity of such skin lesions was ranked in the following order: individual housing > non-littermate group housing > littermate group housing (data not shown). Individual or isolated housing of rodents is widely employed as a model of psychological stress, particularly in the field of psycho-neurological medicine [3,5,9,15,17]. When group-rearing mice in cages, littermate group housing is considered to be a more stable social environment than non-littermate group housing [4,5,17].…”

“…Under individual housing conditions, Swiss white mice were found to show depilation and ulcerative skin lesions at the depilation site caused by scratching [3], BALB/c mice were found to show abnormal proliferation of epidermal cells [15], and hairless mice (HR-1) were found to show delayed recovery from artificial skin barrier disorders caused by tape stripping [9]. Under overcrowded housing conditions, hairless mice (HR-1) were found to exhibit epidermal thickening, accelerated epidermal proliferative activity, a decrease in corneocyte size, and delayed recovery from artificial skin barrier disorders caused by tape stripping [9]. BALB/c mice were found to show moderate exfoliation and slight wrinkle formation on the epidermis and also lowering of skin surface conductance [1].…”