Carbon dioxide laser treatment promotes repair of the three-dimensional network of elastic fibres in rat skin

Background We have previously reported that ultraviolet (UV) B irradiation induces a loss of linearity in the three-dimensional structure of dermal el astic fibres, which results in the reduction of elastic properties of the s kin and leads to wrinkle formation. We further reported that repair of wrin kles by all-trans retinoic acid is accompanied by recovery of the linearity of elastic fibres. Carbon dioxide (CO2) lasers are widely used for treatin g wrinkles in cosmetic surgery. Objectives To perform CO2 laser treatment of wrinkles induced in rat skin b y WE irradiation and to evaluate changes in the three-dimensional structure of dermal elastic fibres during wrinkle repair. Methods Wrinkles were induced in the hind limb skin of Sprague-Dawley rats by UVB irradiation (130 mJ cm(-2) three times weekly for 6 weeks), followed by CO2 laser treatment (11.3 J cm(-2)). The surface appearance of the skin was evaluated by replica observation 6 and 10 weeks after CO2 laser treatm ent followed by measurement of mechanical properties using a Cutometer, Sub sequently, perfusion fixation and digestion with formic acid were performed and elastic fibres were observed by scanning electron microscopy (SEM), Im age analysis of SEM micrographs was carried out to evaluate the linearity i n the three-dimensional structure of elastic fibres, Results Six weeks after CO2 laser treatment, all parameters of skin mechani cal properties in the UVB-irradiated group recovered to levels of the contr ol non-irradiated group, accompanied by repair of wrinkles and a significan t increase in linearity of the three-dimensional structure of elastic fibre s, Conclusions These findings indicate that CO2 laser treatment has a therapeu tic potential to repair wrinkles to non-irradiated levels through recovery of the three-dimensional structure of elastic fibres.