Biophysical, histological and biochemical changes after non-ablative treatments with the 595 and 1320 nm lasers: a comparative study.
OBJECTIVE
The objective was to compare the efficiencies of the 595 nm pulsed dye and the 1320 nm Nd : YAG laser non-ablative rejuvenation.


METHODS
KM mice were irradiated with the 595 nm pulsed dye and the 1320 nm Nd : YAG lasers. Histological changes were evaluated immediately, 1, 7, 21, 30 and 60 days after the two laser treatments. Skin hydration and hydroxyproline content were measured to quantify the degree of improvement of the skin's water-holding capacity and the rate of hydroxyproline synthesis.


RESULTS
Although not statistically significant, the 1320 nm Nd : YAG laser treatment induced 9.7% greater improvement of skin hydration than the 595 nm laser while the 595 nm pulsed dye laser treatment led to a thicker dermis and 8.7% greater increase of hydroxyproline than the 1320 nm laser. More than 50% increase of collagen type I was observed in 75% of 595 nm laser-treated sites and 42% of 1320 nm laser-treated sites, and more than 25% increase of collagen type III was observed in 75% of 595 nm laser-treated sites and 50% of 1320 nm laser-treated sites. The 595 nm laser treatment was better in increasing the amount of collagen fibers, especially collagen type I (P < 0.05).


CONCLUSIONS
Our results demonstrated that the 595 nm laser appeared to be more effective in increasing new collagen formation, while the 1320 nm laser was superior to the 595 nm laser in improving the skin's water-holding capacity.
Institute for Laser Medicine & Biophotonics, Shanghai Jiaotong University, Shanghai, China.
Yongyan
Y
Dang
Qiushi
Q
Ren
Sabine
S
Hoecker
Huaxu
H
Liu
Jingbo
J
Ma
Jinsheng
J
Zhang
D000704:Analysis of Variance; D000818:Animals; D001834:Body Water / Q000378:metabolism; D003094:Collagen / Q000378:metabolism; D020405:Dermis / Q000528:radiation effects; D006909:Hydroxyproline / Q000378:metabolism; D053685:Laser Therapy; D028022:Low-Level Light Therapy; D051379:Mice; D012060:Rejuvenation; D015595:Skin Aging / Q000528:radiation effects*; D014870:Water Loss, Insensible
D003094:Collagen; D006909:Hydroxyproline