Efeito da luz pulsátil na pele normal e no modelo de dois estadios de cancro da pele em murganhos fêmea ICR
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2013-11-15
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A Luz Intensa Pulsátil (IPL) pode ser utilizada para vários fins, nomeadamente no
fotorrejuvenescimento, na correção das alterações vasculares e da pigmentação, do acne, da
remoção de tatuagens e evitar o crescimento do pelo. Os dispositivos IPL produzem um pulso
de luz de duração muito curta e com comprimento de onda entre 500 e 1200nm, ocorrendo
uma absorção seletiva pelos cromóforos presentes no tecido (hemoglobina, melanina e água)
após a sua aplicação. A utilização doméstica destes dispositivos tem aumentado
significativamente nos últimos anos, sendo escassos os estudos sobre os seus efeitos
secundários. O objetivo deste estudo foi compreender a influência da luz pulsátil na pele
normal e no desenvolvimento de lesões cutâneas pré-neoplásicas utilizando um modelo
animal de dois estadios de cancro de pele. Foram utilizados murganhos fêmeas (n=28) da
estirpe ICR (CD-1®), tendo sido constituídos 5 grupos: o grupo I foi submetido ao agente
iniciador 7,12-dimetilbenzentraceno (DMBA), sem mais nenhum tratamento; o grupo II foi
submetido a tratamento com IPL após iniciação pelo DMBA; o grupo III foi submetido a
tratamento com o composto promotor da carcinogénese acetato de tetradecanoilforbol (TPA)
após iniciação com o DMBA; o grupo IV foi exposto só a IPL e o grupo V foi o grupo de
animais controlo, sendo exposto ao veículo, acetona. O procedimento experimental durou 25
semanas. A luz pulsátil foi aplicada na intensidade 5, correspondente a 6,5 J/cm2, numa área
de 6 cm2. No final do procedimento experimental observaram-se 94 lesões proliferativas nos
murganhos do grupo III (DMBA+TPA), sendo 87 papilomas e 7 carcinomas de células
escamosas. A nível histológico, observou-se que a IPL não esteve associada ao
desenvolvimento de neoplasias (grupo II e IV), verificando-se a presença de fibrose dérmica,
o que parece confirmar a sua utilidade clínica no fotorrejuvenescimento. Por outro lado, no
grupo II (DMBA+IPL) verificou-se hiperplasia focal da epiderme em 50% dos animais,
resultado que poderá sugerir a IPL como agente promotor de carcinogénese. Consideramos
fundamental a realização de estudos futuros no sentido de comprovar estes resultados e de
verificar a hipótese da IPL constituir um potencial agente carcinogénico.
Intense Pulsed Light (IPL) may be used for various purposes, namely photo-renewal, correction of vascular alterations and pigmentation, acne, tattoo removal and for the prevention of the growth of hair. IPL devices produce a light pulse of very short duration and with a wavelength between 500 and 1200nm occurring a selective absorption by chromophores present in the tissue (hemoglobin, melanin and water) after its application. The use of these devices has increased significantly at a domestic level in recent years, and there are few studies about its side effects. The aim of this study was to understand the influence of pulsed light on normal skin and in the development of precancerous skin lesions using an animal model of two stages of skin cancer. Female mice were used (n = 28) of ICR strain (CD-1®) and they were incorporated into 5 groups: group I was subjected to initiator, 7,12- dimethylbenz(a)anthracene (DMBA), without further treatment, group II was subjected to pulsed light treatment after the initiation by DMBA and group III was subjected to treatment with the compound of carcinogenesis promoter, 12-o-tetradecanoylphorbol-13-acetate (TPA), after the DMBA initiation, group IV was exposed only to IPL and group V was the control group of animals, being exposed to acetone. The experimental procedure lasted 25 weeks. The IPL was applied at the intensity of 5, corresponding to a fluence of 6.8 J/cm2 in an area of 6 cm2. At the end of the experimental procedure 94 proliferative lesions in mice from group III (DMBA + TPA) were observed, being 87 papillomas and 7 squamous cell carcinomas. At a histological level, it was observed that the IPL was not linked to the development of neoplasia (Group II and IV), identifying the presence of dermal fibrosis, which appears to confirm its usefulness in clinical photorejuvenation. On the other hand, in Group II (DMBA + IPL) focal hyperplasia of epidermis in 50% of the animals was found, a result that may suggest that IPL can be a promoter of carcinogenesis. It should be considered essential to carry out further studies in order to confirm these results and to verify the hypothesis of the IPL as being a potential carcinogen.
Intense Pulsed Light (IPL) may be used for various purposes, namely photo-renewal, correction of vascular alterations and pigmentation, acne, tattoo removal and for the prevention of the growth of hair. IPL devices produce a light pulse of very short duration and with a wavelength between 500 and 1200nm occurring a selective absorption by chromophores present in the tissue (hemoglobin, melanin and water) after its application. The use of these devices has increased significantly at a domestic level in recent years, and there are few studies about its side effects. The aim of this study was to understand the influence of pulsed light on normal skin and in the development of precancerous skin lesions using an animal model of two stages of skin cancer. Female mice were used (n = 28) of ICR strain (CD-1®) and they were incorporated into 5 groups: group I was subjected to initiator, 7,12- dimethylbenz(a)anthracene (DMBA), without further treatment, group II was subjected to pulsed light treatment after the initiation by DMBA and group III was subjected to treatment with the compound of carcinogenesis promoter, 12-o-tetradecanoylphorbol-13-acetate (TPA), after the DMBA initiation, group IV was exposed only to IPL and group V was the control group of animals, being exposed to acetone. The experimental procedure lasted 25 weeks. The IPL was applied at the intensity of 5, corresponding to a fluence of 6.8 J/cm2 in an area of 6 cm2. At the end of the experimental procedure 94 proliferative lesions in mice from group III (DMBA + TPA) were observed, being 87 papillomas and 7 squamous cell carcinomas. At a histological level, it was observed that the IPL was not linked to the development of neoplasia (Group II and IV), identifying the presence of dermal fibrosis, which appears to confirm its usefulness in clinical photorejuvenation. On the other hand, in Group II (DMBA + IPL) focal hyperplasia of epidermis in 50% of the animals was found, a result that may suggest that IPL can be a promoter of carcinogenesis. It should be considered essential to carry out further studies in order to confirm these results and to verify the hypothesis of the IPL as being a potential carcinogen.
Descrição
Dissertação de Mestrado em Biotecnologia para as Ciências da Saúde.
Palavras-chave
Neoplasias , Fibrose , Pele , Ratos (murganho) , Luz pulsátil