X-Message-Number: 24796
Date: Mon, 11 Oct 2004 17:55:51 -0700 (PDT)
From: Doug Skrecky <>
Subject: goodbye grey hair?

Photochem Photobiol. 2004 Jun 1 [Epub ahead of print]
  Oxygen free radicals play a role in the aging process, and the
protective effect of various antioxidants has been intensively studied,
in particular for cutaneous aging. Besides hereditary factors, free
radical mediated damage to melanocytes of the hair follicle has been
considered as a mechanism for aging of the hair. It was the aim of this
study to evaluate the role of photosensitization reactions for hair
greying and to demonstrate potential protective effects of superoxide
dismutase (SOD). Mice with black hair were depilated with the finger tips
on a surface of 6 x 2.5 cm on both sides of the dorsum. The right side
received five applications of a SOD containing gel before exposure to
psoralen (concentration 0.5 mg/ml) plus UVA (365 nm, 4 J/ cm(2)). The
left side was pre-treated in the same way with a gel free of SOD. When
the hair started growing again, the SOD-protected side was
covered with black hair, while the hair on the vehicle-treated side was
grey or white in 27 of the 30 animals studied. The 0.01% SOD
concentration was as protective as the 0.1% concentration.
Heat-inactivated SOD, applied in another 5 animals, was not protective.
Using fluorescent labelling of the SOD with fluorescein isothiocyanate,
epifluorescence microscopy and digital imaging processing, we show that
SOD applied to the skin surface penetrates through the follicular
appendages, as well as through the unbroken stratum corneum. Our findings
suggest that superoxide radicals, generated by interaction of UVA light
with the sensitizer, initiated the formation of secondary products with
well-known DNA-damaging effects, such as lipid peroxidation products and
tumor necrosis factor alpha. SOD prevented the damage to melanocyte DNA
by dismutating superoxide. Photosensitization may be another mechanism for
hair greying, which can be influenced by antioxidants. Given the large
number of exogenous and endogenous sensitizers, this mechanism deserves
further study for human hair greying.

Am J Vet Res. 1994 Nov;55(11):1593-6.
Coat color darkening in a dog in response to a potent melanotropic peptide.
  Analogues of a melanocyte-stimulating hormone (alpha-MSH) have been
documented to be effective in inducing integumental melanogenesis in
several species. These melanotropin analogues are more potent than the
natural hormone and have prolonged biological activity, without apparent
teratogenic or other toxic effects, at least in rodents. In a pilot study,
a cyclic alpha-MSH analogue, Ac-[Nle4, Asp5, D-Phe7, Lys10]
alpha-MSH4-10-NH2, was administered SC to a dog at a dose of 1 mg of
analogue in 1 ml of 0.9% NaCl for 3 weeks, without noticeable adverse
effects. There was gradual and extensive darkening of the coat, which
originally was predominantly tan, with tips of black. Initially, the
darkening involved face and extremities, then gradually expanded to
include the trunk and tail hair. Visual pigmentation peaked approximately
2 months after injections were completed. As new hair growth
continued subsequent to the injections, the original tan color appeared
at the proximal end of the hair shaft, leaving a dark terminal band on
all affected hairs. These observations clearly indicated that follicular
melanogenesis can be induced in dogs by treatment with a melanotropic

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