Nonablative skin remodeling is a new light treatment approach for photodamaged skin. Compared to ablative CO2 or
Er:YAG laser resurfacing, dermabrasion, and chemical peels, the clinical objective of nonablative skin remodeling is to
maximize thermal damage to upper dermis while minimizing injury to the epidermis and surrounding tissue,
consequently decreasing potential complications and shortening long recuperation periods.
Histological analysis of preoperative and postoperative biopsies using H&E or special stains has indicated the dermal
thermal injury, which resulting in collagen denaturation, is the most important mechanism of nonablative skin
remodeling for improving skin situation. And the extent of improvement of skin situation corresponded to the formation
of a new band of dense, compact collagen bundles in the papillary dermis. The diversity of individual skin condition
influences the choice of pulsed light treatment parameters, and further influences the degree of dermal thermal damage,
thus the efficacy of nonablative skin remodeling remains unstable.
Recently, multiphoton microscopy has show a promising application for monitoring skin thermal damage, because
collagen could produce strong second harmonic generation (SHG). And SHG intensity is presumably proportional to the
percentage of collagen in dermis. In this paper, the auto-fluorescence (AF) intensity and SHG intensity of mice skin
irradiated by pulsed Nd:YAG laser were measured and imaged with multiphoton microscope, and the results show the
ratio of SHG to AF decreases with the increase of irradiation exposure dose, and could be a quantitative technique to
assess dermal thermal damage, and could further benefit the choice of light treatment parameters.