Anais Brasileiros de Dermatologia (Aug 2011)
Modelos experimentais de desnutrição e sua influência no trofismo cutâneo Experimental models of malnutrition and its effect on skin trophism
Abstract
FUNDAMENTOS: A pele, para exercer suas funções, necessita de níveis adequados de nutrientes. OBJETIVO: Analisar o trofismo cutâneo de ratos nutridos e desnutridos por meio de dois modelos de desnutrição. MÉTODOS: No Modelo Marasmo, utilizaram-se 60 ratos Wistar em controle dietético, dos quais 30 foram selecionados aleatoriamente para receber metade da dieta diária durante 60 dias. No Modelo Gelatina, empregaram-se 60 ratos, dos quais 30 receberam dieta associada a proteína de baixa qualidade (gelatina) durante 30 dias. Avaliou-se o estado nutricional dos animais por meio da massa corporal, dos sinais clínicos e da dosagem de albumina sérica. Após o período de desnutrição, fez-se a histologia da pele dos animais para análise da espessura da derme e epiderme com o software Leica Application Suite; nas lâminas coradas com tricrômio de Gomori, analisou-se a colagênese com o software ImageJ. RESULTADOS: A massa corporal dos animais desnutridos pelo marasmo e gelatina foi significativamente menor (pBACKGROUND: The skin requires adequate levels of nutrients to function properly. OBJECTIVE: To analyze skin trophism in well-nourished and undernourished rats using two models of malnutrition. METHODS: In the marasmus model, 60 Wistar rats were kept on a controlled diet, 30 being randomly selected to receive half the established diet for 60 days. In the gelatin model, 60 rats were used, 30 of which received a diet consisting of poor quality protein (gelatin) for 30 days. The nutritional status of the animals was evaluated according to body mass index, clinical signs and serum albumin measurement. After the period of malnutrition, histology was performed on the animals' skin to analyze the thickness of the dermis and epidermis using the Leica Application Suite software. Collagen was analyzed on slides stained with Gömöri trichrome using the ImageJ software program. RESULTS: The body mass index of the malnourished animals in the marasmus and gelatin groups was significantly lower than that of the well-nourished animals in the two groups (p<0.0001 in both models). With respect to serum albumin, there was no difference between the groups in either of the two models. In relation to the histological analysis of skin thickness, the dermis of the malnourished animals was significantly thinner compared to that of the well-nourished animals (p<0.0001 in both models). The percentage of collagen was lower in the malnourished animals compared to the well-nourished animals (p<0.0005 and p<0.003 in the marasmus and gelatin model, respectively). CONCLUSIONS: Skin thickness measurements were lower in the malnourished animals in both models, and this finding was histologically confirmed by the lower percentage of collagen, showing the negative effect of malnutrition on skin trophism
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