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Advisor(s)
Abstract(s)
A pele é o maior órgão do corpo humano e está envolvida na preservação da
homeostase dos fluidos do corpo, na regulação térmica e na protecção contra agentes
infecciosos. Após uma lesão, a pele tem de ser revestida de forma a diminuir a dor, a
contaminação, o risco de infecção e a desidratação do paciente.
O processo de regeneração de uma lesão cutânea é complexo e envolve uma resposta
integrada de vários tipos de células e factores de crescimento.
No presente estudo foi avaliado a aplicabilidade de um hidrogel, à base de quitosano,
no tratamento de lesões de pele. A morfologia do hidrogel foi caracterizada através de
imagens de microscopia electrónica de varrimento. A biocompatibilidade e biodegrabilidade
deste biomaterial foi avaliada através de ensaios in vitro e in vivo. Os fibroblastos isolados da
pele de ratos Wistar, foram usados como modelos nos ensaios in vitro, de modo a avaliar a
citotoxicidade do hidrogel. Os fibroblastos aderiram e proliferaram na presença do biomaterial
em estudo, o que permitiu concluir a ausência de citotoxicidade deste, assim como dos
produtos resultantes da sua degradação. A aplicabilidade do hidrogel no tratamento de lesões
cutâneas foi avaliada em ratos Wistar, por indução de lesões profundas na pele. O processo de
cicatrização da lesão foi monitorizado macroscopicamente e por análise histológica. A análise
macroscópica revelou que as queimaduras dos animais tratados com o hidrogel de quitosano
cicatrizaram mais rapidamente do que os animais usados como controlo. A análise histológica
revelou a ausência de reacção inflamatória ou anormalidades patológicas nos órgãos obtidos
por necrópsia nos animais tratados com o hidrogel, o que suporta a histocompatibilidade local
e sistémica do biomaterial. Os resultados obtidos sugerem que este biomaterial poderá ajudar
a restabelecer a estrutura da pele.
Skin is the largest organ of the human body, and plays different functions in the organism. Skin is involved in homeostasis of the body, thermal regulation and protection against infectious agents. After a skin damage, it must be coated in order to diminuish pain, contamination, risk of infection and dehydration Wound healing is a complex process involving an integrated response by many different cell types and growth factors, in order to achieve rapid restoration of skin architecture and function. In the present study, the applicability of a chitosan hydrogel as wound dressing has been evaluated. Chitosan hydrogel morphology has been analysed by scanning electron microscopy. Fibroblast cells isolated from rat skin were used to assess cytotoxicity of the hydrogel. Chitosan hydrogel was able to promote cell adhesion and proliferation. Cell viability studies showed that hydrogel and its degradation by‐products are non‐cytotoxic. The evaluation of the applicability of chitosan hydrogel in the treatment of dermal burns in Wistar rats was performed by induction of full‐thickness transcutaneous dermal wounds. Wound healing was monitored through macroscopic and histological analysis. From macroscopic analysis, the wound beds of the animals treated with chitosan hydrogel were considerably smaller than those of the controls. Histological analysis revealed lack of reactive or granulomatous inflammatory reaction in skin lesions with chitosan hydrogel and the absence of pathological abnormalities in the organs obtained by necropsy, which supported the local and systemic histocompatibility of the biomaterial. The present results suggest that this biomaterial may help the re‐establishment of skin architecture.
Skin is the largest organ of the human body, and plays different functions in the organism. Skin is involved in homeostasis of the body, thermal regulation and protection against infectious agents. After a skin damage, it must be coated in order to diminuish pain, contamination, risk of infection and dehydration Wound healing is a complex process involving an integrated response by many different cell types and growth factors, in order to achieve rapid restoration of skin architecture and function. In the present study, the applicability of a chitosan hydrogel as wound dressing has been evaluated. Chitosan hydrogel morphology has been analysed by scanning electron microscopy. Fibroblast cells isolated from rat skin were used to assess cytotoxicity of the hydrogel. Chitosan hydrogel was able to promote cell adhesion and proliferation. Cell viability studies showed that hydrogel and its degradation by‐products are non‐cytotoxic. The evaluation of the applicability of chitosan hydrogel in the treatment of dermal burns in Wistar rats was performed by induction of full‐thickness transcutaneous dermal wounds. Wound healing was monitored through macroscopic and histological analysis. From macroscopic analysis, the wound beds of the animals treated with chitosan hydrogel were considerably smaller than those of the controls. Histological analysis revealed lack of reactive or granulomatous inflammatory reaction in skin lesions with chitosan hydrogel and the absence of pathological abnormalities in the organs obtained by necropsy, which supported the local and systemic histocompatibility of the biomaterial. The present results suggest that this biomaterial may help the re‐establishment of skin architecture.
Description
Keywords
Hidrogel de quitosano Pele - Aspectos fisiológicos Pele - Aspectos fisiológicos Pele - Cicatrização Pele - Hidrogel de quitosano