Dover, 1998  Title: Pigmented guinea pig skin irradiated
with Q-switched ruby laser pulses. Morphologic and histologic
findings.
Authors: Dover JS, Margolis RJ, Polla LL, Watanabe
S, Hruza GJ, Parrish JA, Anderson RR
Journal: Arch Dermatol 1989 Jan;125(1):43-9
PMID: 2910206, UI: 89087142
Affiliated institution: Department
of Dermatology, Wellman Laboratory, Harvard Medical School, Massachusetts
General Hospital, Boston.
Cited in: Dierickx
Q-switched ruby laser pulses cause selective damage
to cutaneous pigmented cells. Repair of this selective damage
has not been well described. Therefore, using epilated pigmented
and albino guinea pig skin, we studied the acute injury and tissue
repair caused by 40-ns, Q-switched ruby laser pulses. Gross observation
and light and electron microscopy were performed. No specific
changes were evident in the albino guinea pigs. In pigmented animals,
with radiant exposures of 0.4 J/cm2 or greater, white spots confined
to the 2.5-mm exposure sites developed immediately and faded over
20 minutes. Delayed depigmentation occurred at seven to ten days,
followed by full repigmentation by four to eight weeks. Regrowing
hairs in sites irradiated at and above 0.4 J/cm2 remained white
for at least four months. Histologically, vacuolation of pigment-laden
cells was seen immediately in the epidermis and the follicular
epithelium at exposures of 0.3 J/cm2 and greater. Melanosomal
disruption was seen immediately by electron microscopy at and
above 0.3 J/cm2. Over the next seven days, epidermal necrosis
was followed by regeneration of a depigmented epidermis. By four
months, melanosomes and melanin pigmentation had returned; however,
hair follicles remained depigmented and devoid of melanocytes.
This study demonstrates that selective melanosomal disruption
caused by Q-switched ruby laser pulses leads to transient cutaneous
depigmentation and persistent follicular depigmentation. Potential
exists for selective treatment of pigmented epidermal and dermal
lesions with this modality.
|
|
