Wound Healing: Effects of Closing Tension, Zyplast™, and Platelet‐Derived Growth Factor

Abstract

Previous studies have shown that beginning 5 to 7 days from wounding, the tensile strength of wounds closed under tension in rats is significantly higher than the tensile strength of wounds closed without tension. This study evaluated the effects of increased closing tension, zyplast implant (ZI), and human recombinant platelet-derived growth factor (PDGF) on the tensile strength of wounds. Six groups of 12 rats each were divided into two main subsets: wounds were closed without tension in three groups and with high tension of approximately 100 g in the three other groups. In both no-tension and high-tension groups, one subgroup received no intervention (controls), one subgroup received ZI (zyplast controls), and one subgroup received ZI-PDGF (ZI used as a carrier for PDGF). Healing was evaluated by tensile strength determinations at 5 days. For the controls, wounds closed under tension showed a trend toward higher tensile strength, but statistical significance was not reached. Compared with controls, tensile strength was 45% lower in the wounds with ZI and closure with tension (P = .0063) and 38% lower in the wounds with ZI and closure without tension (P = .007). Treatment with ZI-PDGF resulted in 69% higher tensile strengths (P = .049) as compared with ZI controls for wounds closed with tension. This study demonstrated the beneficial effect of PDGF in accelerating healing in wounds closed under tension. Although ZI was able to deliver PDGF to the wound, the use of this substance as a carrier is questioned since it was detrimental to healing.

Keratinocyte-derived growth factors play a role in the formation of hypertrophic scars

“…In contrast with TGF‐β1, PDGF seems to exhibit a dual effect in scar tissue formation. It has an important positive effect when it accelerates wound‐healing processes in the early stages65, 66, but plays a negative role in the induction of various fibrotic conditions, such as scleroderma or liver and pulmonary fibrosis67, in the later stages. This duality is also shown by the increased dermal PDGF expression in our normal scars at 3 months and reduced expression at 12 months (Tables 2 and 3)65.…”

A comparative study of colour and perfusion between two different post surgical scars. Do the laser Doppler imager and the colorimeter measure the same features of a scar?

“…Biomechanical forces have long been considered influential in scar morphogenesis and the completion of the remodelling phase. The degree of biomechanical force is influenced by the type of wound, the wound location and the orientation of the wound in relation to the axis of the body .…”