Acta anat. 103: 134-141 (1979)

Stress and wound healing Irene Cohen Department of Anthropology, Hunter College, C.U.N.Y., New York, N.Y., USA

Key words. Stress • Cold • Heat • Noise • Mice • Primary wound activity • Rate of healing

Introduction Stressors are stimuli which create a certain pattern of responses in the bodies of mammals. Among the most important responses to stressful stimulation, like infection, intoxication and muscular fatigue, are the following: (I) increased adrenocorticotrophic out­

put by the pituitary, (2) increased output of adrenal cortical and medullary hormones, (3) changes in protein, glucose and lipid metabolism and (4) thymicolymphaticinvolution [Selve. 1955; Turner and Bagnara, 1971], All of these events will affect maintenance, growth and repair of the skin. Continued stimulation of the

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Abstract. An experiment was performed to compare the effects of stressors - cold, heat and noise - on primary wound activity (i.e., wound closure in the first 24 h after wound infliction) and on rate of healing in mice. A significant correlation was found between reduced primary wound activity and a faster rate of healing. Conversely, a correlation was found between rela­ tively greater primary wound activity and a slower rate of healing. A possible explanation of this correlation is a compensatory mechanism inherent to the skin healing process. This mechanism is visualized as ( I) stress exposure affecting the skin by (a) caus­ ing it to become thinner and tauter and (b) causing it to have less elastic recoil: therefore. (2) when a square wound is produced in stressed skin, (a) the wound does not recoil readily or gapes soon after cutting and (b) a longer wound perimeter results. Because there is evidence that rate of healing is governed by cells on the wound perimeter, the greater the perimeter, the greater the number of cells that will undergo rapid mitosis and the faster will be the rate of healing. Therefore, stressed skin will heal at a faster rate, compen­ sating for the loss of elasticity and cellular depletion caused by stress. This study is of interest to anthropology because it deals with dynamic adaptation, trying to grasp the meaning of the elusive endocrine interface between environmental stimulation and a measurable physical entity like healing. This w'ork may have revealed a functional complex that is common to the healing of all mammalian skin, whereby retarding effects of stress on the healing process are obviated.


changes in the skin than studies of stressor-induced hormone influence on wound healing. To our knowledge, neither the relationship between stress and primary wound activity (i.e., closure of wound borders in the first 24 h after wound infliction) nor the relevance of when stress exposure takes place with respect to the time of wound infliction has been studied. Therefore, an experiment was designed to compare the effects of environmental stressors - cold, heat and noise - on primary wound activity (closure of wound 24 h after infliction) and on the rate of wound healing in mice. By comparing groups exposed to stres­ sors before wounding to those exposed to stressor after wounding and all during the healing process, the effect of timing of stress on healing was explored. This study is important to anthropologists in that it deals with dynamic adaptation, and tries to show how' an adaptive complex, intrinsic to the skin tissue itself, may compensate for the potentially retarding effects of stress.

Materials and methods Experimental method 119 CF-I Carworth random bred mice were used as subjects. They were randomly allotted to 7 groups: control, cold-before, cold-during, heat-before, hcatduring, noise-before, noise-during. An area of approximately 8.5 cm in circumference was shaved on the caudal half of the back of each subject, and a rubber stamp outline (0.5 * 0.5 cm) was applied to the depilated skin with blue food color. The subjects were anesthetized, and the skin was incised along the border of the outline and removed down to the muscle fascia. After a rest period of 24 h, die wound was measured once daily, by outlining it on clear acetate and weighing the acetate facsimile on a Mcttlcr semi-microanalytic balance (0.01-mg accuracy), until healing was complete. Healing was judged to be com­ plete when the wound was entirely closed and the scab had fallen off. Prior to the experiment, the acetate was checked for uniformity of thickness, using a micrometer (32 measurements: 0.11±0.003 mm), and for uniformity of weight of0.5-cm-’cutouts (4.82 ±0.027 mg clean, and 4.96± 0.047 mg finger-smudged). The mean weight of smudged acetate was significantly greater than that of clean acetate (t = 2.28, p

Stress and wound healing.

Acta anat. 103: 134-141 (1979) Stress and wound healing Irene Cohen Department of Anthropology, Hunter College, C.U.N.Y., New York, N.Y., USA Key wo...
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