[Effect of alexandrite laser treatment for hair removal in Tibet mini-pigs].
OBJECTIVE
To observe the histological and ultrastructural changes of the skin and hair follicles following hair removal by alexandrite laser in Tibet mini-pigs.


METHODS
Twelve healthy Tibet mini-pigs with dark hair were treated with alexandrite laser for hair removal. The skin specimens were taken immediately and at 1 h and 1, 3, 5, 10, 15, 30, 60 days after the laser treatment for observation under optical and transmission electron microscope.


RESULTS
Laser hair removal resulted in extensive coagulation necrosis, carbonization and falling of the subcutaneous hair shafts, and some of the cells in the outer root sheath and hair bulb underwent degenerative and necrotic changes. One hour after laser treatment, the cells in the outer root sheath and bulb exhibited nuclear condensation, fragmentation and or karyolysis characteristic of cell apoptosis. The cell apoptosis reached the peak level on day 3 after the laser exposure, accompanied by endothelial degeneration in the hair papilla vessels, edema and lymphocyte infiltration in the dermal tissues. Tissue reaction and inflammation were relieved on day 5, and the dermal tissue and follicles recovered their normal structures on day 10. At 60 days after the treatment, the hair follicles decreased markedly but the structure of the residue follicles remained normal.


CONCLUSIONS
Alexandrite laser exposure results in selective destruction of the follicles by inducing direct coagulation and cell apoptosis to achieve permanent hair removal. Tibet mini-pigs with black hair can be used as the animal model of clinical laser hair removal.
Zeng
Dong
D
Department of Plastic Surgery, General Hospital of Guangzhou Command, Guangzhou 510010, China.
Yu
Wen-lin
WL
Bi
Yuan
Y
Yang
Chuan-hong
CH
Lai
Huang-wen
HW
Hu
Zhi-qi
ZQ
D000818:Animals; D018859:Hair Follicle / Q000528:radiation effects / Q000648:ultrastructure; D006204:Hair Removal / Q000379:methods*; D053844:Lasers, Solid-State / Q000627:therapeutic use*; D046529:Microscopy, Electron, Transmission; D013552:Swine; D018609:Tibet