RESUMEN
BACKGROUND: Improvement in the appearance of wrinkles has been observed following exposure to short-pulsed 585 nm laser light. The assumed effect is a specific absorption of light in the blood vessels of the superficial dermis, resulting in release of inflammatory mediators into the interstitium followed by stimulated fibroblast activity. The fibroblasts effectively initiate tissue repair mechanisms, which include enhanced new collagen production. METHODS: Quantitative measures of collagen synthesis rate in the skin can be obtained from determinations of the aminoterminal propeptide of type III procollagen level in suction blister fluid using a radioimmunoassay. RESULTS: A single laser treatment at subpurpura energy level showed that the 585 nm laser source induced an increase of 84% (p < 0.05) in the type III procollagen production rate compared with a non-treated control site. A broadband, pulsed, white light source at 4 J/cm(2) showed no measurable increase, whilst the skin area treated with 7 J/cm(2) increased the procollagen production rate by 17% (NS, p > 0.05). A second treatment 2 weeks later further improved the laser-induced increase in procollagen production rate to 148% (p < 0.05) compared with the control site. The broadband, pulsed, white light-irradiated skin sites showed that at 4 J/cm(2) the procollagen production rate was increased by 21.4% and at 7 J/cm(2) by 32.1% compared with the corresponding non-treated control site (NS, p > 0.05). CONCLUSIONS: Irradiation by the haemoglobin-specific short-pulsed 585 nm laser induced a fivefold increase in procollagen production rate compared with a biologically comparable fluence delivered in a broadband spectrum. An additional treatment after 2 weeks further increased the effect of the short-pulsed 585 nm laser to 148% of the control. Vascular-specific light/tissue interactions seem to play a key role in stimulating skin collagen production.