Skin suction blister wound exposed to u.v. irradiation: a burn wound model for use in humans

The effects of exposing blister wounds to u.v. irradiation were assessed in 14 male volunteers, on whose forearms blister wounds (diameter 5 mm, suction set at 200 mmHg below atmospheric for 2 h 15 min, blister roof cut at base), and irradiated blister wounds (as above, in addition u.v. irradiation given selectively for 30 min from a distance of 10 cm), were produced. In non-u.v.-irradiated wounds, flow cessation, assessed by video microscopy (n = 6), was observed in a small proportion of the papillary loop vessels. The oedema adjacent to the wound was poorly developed. Laser Doppler linear scans (n = 8) demonstrated a pronounced hyperaemia in the wound bed and also in the adjacent skin, the reaction subsiding over a few days. The exudation rate, determined by weighing the hydrocolloid dressings applied to the wound, was maximal on day 1 and then rapidly decreased. Epithelialization, assessed evaporimetrically as the time taken for reinstatement of the epidermal water barrier, was complete in 5.1 days. In the u.v.-irradiated wounds the blood flow had ceased in all the papillary loop vessels by day 1, and increased oedema, exudation and hyperaemia at the wound edges were observed. Epithelialization was not significantly retarded by the irradiation injury. After 6 months, slight discolouration of the skin was occasionally observed, but no cosmetically disturbing scars. This benign and standardized wound model in humans--based on a combination of a mechanical suction injury and a superficial radiation burn--may prove to be useful, for instance when studying the effects of burns treatment.