Biomedical Engineering Reference
In-Depth Information
Fig. 8.2
Contraction dominated regeneration as a mode of wound closure with increasing devel-
opment of the tadpole (larva). The broken line connecting the experimental data divides the wound
closure diagram into three regions, each corresponding to a mode of defect closure: regeneration,
contraction, scar formation. The percentage of each closure mode is indicated by the length of the
ordinate inside the respective region. Regeneration and contraction, without scar formation, com-
bined to close the dermis-free defects in the tadpole at four stages of development. Scar formation
(
indicated by the cross-hatched region at bottom right
) was first observed after metamorphosis,
the transition from tadpole to adult frog (Yannas et al. 1996).
skin in the ear regenerates completely, including the synthesis of hair follicles and
sebaceous glands; scar has not been observed in the rabbit ear defect (Fig.
8.3
) (Jo-
seph and Dyson 1966; Goss 1980, 1992; Goss and Grimes 1972, 1975).
Contraction in the rabbit dorsal wound was estimated at 96 ± 1 % (percent total
initial wound area closed by contraction), while the remainder is estimated as being
scar (Kennedy and Cliff 1979) (Table 4.3). In contrast, contraction of the ear hole
wound in the rabbit ear was estimated at only 3 ± 3 of total wound area while the
remainder of the wound area closed by regeneration. The striking lack of contrac-
tion in the rabbit ear defect has been attributed to particularly tight binding of the
