An Antagonistic Relation Between Wound Contraction and Regeneration - Tissue and Organ Regeneration in Adults - page 216

Fig. 8.5 Orientation of myofibroblasts on the surface of a contracting skin wound in the guinea
pig (day 10). Myofibroblasts (MFB) were stained red-brown with an antibody to alpha smooth
muscle actin, their characteristic phenotype. (From Troxel 1994)

evidence of mechanical tension inside the closed-skin defect highlights the impor-
tance of subdermal tissues during wound closure (Fig. 8.6 ). There is a sharp contrast
between these compliant subdermal tissues in the guinea pig wound and the dermis
in the rabbit ear wound model which adheres tenaciously to the underlying cartilage
layer (Joseph and Dyson 1966; Goss 1980, 1992; Goss and Grimes 1972, 1975;
Mustoe et al. 1991). This comparison suggests the possibility that the mechanical
compliance of subdermal tissues is a significant factor in the magnitude of contrac-
tion forces generated in skin wounds.
Mechanical forces that contribute to wound closure in skin are not limited to
those that deform by contraction. Observations made with guinea pig skin wounds
have shown that other tissue movements, including an initial expansion of the

scar

dermal edge

dermal edge

deformed subdermal tissue

Fig. 8.6 Deformation of subdermal tissues in a contracting skin defect in the guinea pig. Observed
by polarized light microscopy following spontaneous closure of an excisional full-thickness skin
defect in the guinea pig. Left, right : Dermal edges are separated by scar. Top center : Scar. Bottom
right : Highly deformed birefringent fibers (probably stretched collagen fibers) underneath scar
and adipose layer. Bar : 500 µm. (From Troxel 1994)