Development and Assessment of a Cutaneous Tissue Stretch Device As Scar Therapy

Purpose: Mechanical force plays an important yet incompletely understood
role in scar formation(1-3). Tension during the wound healing process may
affect collagen deposition and TGF-β1 production (1). The purpose of the
present study was to develop and test a device that produces parallel
stretch on new scars and to analyze its potential to reduce scarring.

Methods: Thirty-six mice with identical scars were randomized into three
treatment groups (0.5X, 1X, or 2X device strength). Animals were treated
for 10 days and their scars were scored using the Vancouver Scar Scale.
Scar tissue samples were compared between treatment groups by
histological analysis and TGF-β1 between control and treatment groups
was measured by ELISA.

Results:
Scar morphology scores from 0.5X and 1X stretch groups were
significantly lower than the control scar group (p<0.05).  Scar scores from
the 1X treatment group were also significantly lower when compared to the
0.5 X group (p<0.05). Histological analysis demonstrated that sham, control
scar and 2X groups showed more collagen deposition and a thicker dermal
scar than the 0.5x and 1x treatment groups. The dermis in unstretched
scars had fewer fibroblasts with more collagen between cells when
compared with the 0.5x fibroblasts and 2x group. TGF-β1 levels were
significantly lower in the stretch treatment groups 0.5x (342.1±9) and 1x
(254.1 ±3) when compared to the control scar group (p<0.05). TGF-β1
levels in the 1X treatment group were also significantly lower than the 0.5X
treatment group (p<0.05).

Conclusion: Intermittent cutaneous tissue stretch parallel to the scar during
the proliferative phase of wound healing can decrease scar formation on a
macroscopic, microscopic and biochemical level.