Establishment of a 2-week canine skin organ culture model and its pharmacological modulation by epidermal growth factor and dexamethasone.

Although canine skin models are already available as either monocellular or organotypic cultures, they only partly recapitulate normal skin morphological features and function. The objective of this study was to establish a canine serum-free skin organ culture model and verify whether dexamethasone could rescue epidermal growth factor-induced changes. The study of morphological changes as a response to pharmacological substances may indeed help to investigate skin physiology and pathology. Normal skin was obtained from five client-owned dogs subjected to surgical procedures unrelated to dermatological conditions. Two experimental designs were performed: (i) two-week viability of the skin culture; (ii) dexamethasone (DMS) inhibition of epidermal growth factor (EGF)-induced effects. Serum-free submerged organ cultures were established in Williams' E medium supplemented with penicillin-streptomycin, insulin, hydrocortisone and l-glutamine. General morphological features of skin anatomical structures were well maintained up to day 14, scattered pyknotic nuclei were visible in the epidermis from day 7. Normal keratinocyte differentiation was confirmed by cytokeratin (K) 10, K14 and loricrin immunostaining. Epidermal thickness did not decrease throughout the study. A decrease in keratinocyte proliferation was observed at day 7 and 14. Treatment with EGF induced both keratinocyte proliferation and thickening of the epidermis; both responses were counteracted by DMS. Treatment with EGF increased the length of epithelial tongues at the edge of the skin explants; this effect was further enhanced by DMS supplementation. Our findings demonstrate the potential use of a full-thickness canine skin organ culture model for the study of skin physiology and pharmacological response to exogenous compounds, especially in the field of re-epithelialisation and keratinization disorders.

Tissue engineering in wound repair: the three "R"s--repair, replace, regenerate.

Horses are predisposed to traumatic wounds that can be labor intensive and expensive to manage. Skin has a considerable potential for efficient and functional repair however, while cutaneous repair is a regenerative process in the fetus, this capability declines in late gestation as inflammation and scarring alter the outcome of healing. The historical gold standard for replacement of lost skin is the autologous skin graft. However, the horse's lack of redundant donor skin limits the practicality of full-thickness grafting to smaller wounds; moreover, graft failure is relatively common in equine patients as a result of infection, inflammation, fluid accumulation beneath the graft, and motion. Tissue engineering has emerged as an interdisciplinary field with the aim to regenerate new biological material for replacing diseased or damaged tissues or organs. In the case of skin, the ultimate goal is to rapidly create a construct that effects the complete regeneration of functional skin, including all its layers and appendages. Moreover, an operational vascular and nervous network, with scar-free integration within the surrounding host tissue, is desirable. For this to be achieved, not only is an appropriate source of cells required, but also a scaffold designed from natural or synthetic polymers. The newly created tissue might finally meet the numerous needs and expectations of practitioners and surgeons managing a catastrophic wound in a horse.

Utilização de película de poliuretano na síntese cutânea de gatas após celiotomia / Use of polyurethane film in skin closure of cats after celiotomy

Introdução - A película de poliuretano é um filme transparante, semipermeável e autoadesivo, primeiramente utilizada em queimaduras e na proteção de cateteres venosos centrais em unidades de terapia intensiva. Sua principal propriedade é a constituição de uma barreira capaz de proteger a pele lesada contra colonização bacteriana, sem impedir trocas gasosas entre tecido e ambiente. O presente estudo, objetivou avaliar as vantagens do emprego deste adesivo como técnica alternativa na síntese cutânea de felinos domésticos submetidos a laparotomia. Métodos - Foram utilizadas 25 gatas, nas quais realizou-se celiotomia mediana para ovariosalpingohisterectomia eletiva. Os procedimentos pré e trans-cirúrgicos foram habituais com preparo de rotina e do campo operatório, seguido por celiotomia pré-retroumbical, ligaduras dos pedículos e corpo uterino com fio de nylon 2-0 e sutura da linha alba com o mesmo material em pontos simples separados. Após aproximação do tecido subcutâneo com fio categute 4-0, foi empregada bandagem porosa adesiva hipoalergênica para cooptação das margens da ferida cirúrgica cutânea, seguida pela aplicação de película de poliuretano. Resultados - Todos animais foram reexaminados sete dias após o ato operatório, momento no qual a película foi removida. Não houve deiscência ou sinais de infecção em nenhum dos animais. No entanto, quatro gatas apresentaram eritema localizado na região de aplicação do material, o qual foi tratado com iodo povidine durante três dias consecutivos. Conclusão - Por meio dos resultados obtidos, conclue-se que o uso da película de poliuretano na pele em substituição às suturas convencionais após a realização de celiotomia representa procedimento mais rápido e prático que as técnicas usualmente utilizadas com este fim.

Contração de feridas após cobertura com substitutos temporários de pele / Contraction of wound after cover with temporaly skin substitutes

Feridas experimentais foram recobertas com substitutos temporários de pele produzidos com poliuretano, hidrocolóide, hemicelulose e vaselina e com gaze, para avaliaçäo do cálculo da área e percentual de contraçäo ao 7§, 14§ e 28§ dias de evoluçäo. O curativo hidrocolóide proporcionou uma reduçäo da área inicial ao sétimo dia, näo se observando diferenças significativas entre os tratamentos nos períodos seguintes.