Bio-Conjugated Polycaprolactone Membranes: A Novel Wound Dressing

BACKGROUND: The combination of polycaprolactone and hyaluronic acid creates an ideal environment for wound healing. Hyaluronic acid maintains a moist wound environment and accelerates the in-growth of granulation tissue. Polycaprolactone has excellent mechanical strength, limits inflammation and is biocompatible. This study evaluates the safety and efficacy of bio-conjugated polycaprolactone membranes (BPM) as a wound dressing. METHODS: 16 New Zealand white rabbits were sedated and local anaesthesia was administered. Two 3.0x3.0 cm full-thickness wounds were created on the dorsum of each rabbit, between the lowest rib and the pelvic bone. The wounds were dressed with either BPM (n=12) or Mepitel (n=12) (control), a polyamide-silicon wound dressing. These were evaluated macroscopically on the 7th, 14th, 21st, and 28th postoperative days for granulation, re-epithelialization, infection, and wound size, and histologically for epidermal and dermal regeneration. RESULTS: Both groups showed a comparable extent of granulation and re-epithelialization. No signs of infection were observed. There was no significant difference (P>0.05) in wound size between the two groups. BPM (n=6): 8.33 cm2, 4.90 cm2, 3.12 cm2, 1.84 cm2; Mepitel (n=6): 10.29 cm2, 5.53 cm2, 3.63 cm2, 2.02 cm2; at the 7th, 14th, 21st, and 28th postoperative days. The extents of epidermal and dermal regeneration were comparable between the two groups. CONCLUSIONS: BPM is comparable to Mepitel as a safe and efficacious wound dressing.

Creation of Consistent Burn Wounds: A Rat Model

BACKGROUND: Burn infliction techniques are poorly described in rat models. An accurate study can only be achieved with wounds that are uniform in size and depth. We describe a simple reproducible method for creating consistent burn wounds in rats. METHODS: Ten male Sprague-Dawley rats were anesthetized and dorsum shaved. A 100 g cylindrical stainless-steel rod (1 cm diameter) was heated to 100degrees C in boiling water. Temperature was monitored using a thermocouple. We performed two consecutive toe-pinch tests on different limbs to assess the depth of sedation. Burn infliction was limited to the loin. The skin was pulled upwards, away from the underlying viscera, creating a flat surface. The rod rested on its own weight for 5, 10, and 20 seconds at three different sites on each rat. Wounds were evaluated for size, morphology and depth. RESULTS: Average wound size was 0.9957 cm2 (standard deviation [SD] 0.1845) (n=30). Wounds created with duration of 5 seconds were pale, with an indistinct margin of erythema. Wounds of 10 and 20 seconds were well-defined, uniformly brown with a rim of erythema. Average depths of tissue damage were 1.30 mm (SD 0.424), 2.35 mm (SD 0.071), and 2.60 mm (SD 0.283) for duration of 5, 10, 20 seconds respectively. Burn duration of 5 seconds resulted in full-thickness damage. Burn duration of 10 seconds and 20 seconds resulted in full-thickness damage, involving subjacent skeletal muscle. CONCLUSIONS: This is a simple reproducible method for creating burn wounds consistent in size and depth in a rat burn model.