RESUMEN
We studied the development of respiratory tract in bovine embryos by light microscopy and transmission electronic microscopy. This process was observed formation of laryngeal-tracheal tube in embryos that present crown-rump (CR) length of 9.0 mm (20/21 days of pregnancy) at around the fourth gestational week; the organ wall appears to be formed of epithelium comprising several cell layers and supported by mesenchyme. Within the lungs, the areas subjacent to epithelium present condensed mesenchyme, while more distal areas loose mesenchyme, in which blood vessels beginn to form, as the organ is in a pseudo-glandular phase. Ultra-structurally, the mesenchyme cells present irregular shapes, having a stellar or fusiform appearance and are united by desmosomes, where the cytoskeleton attaches to the cellular membrane, forming a connection. The bifurcation of trachea caudal portion in the main bronchia is simultaneous to the appearance of the tracheal bronchi, during the fifth gestational week.
Asunto(s)
Bovinos/embriología , Sistema Respiratorio/embriología , Animales , Sistema Respiratorio/ultraestructuraRESUMEN
Burns are serious consequences of trauma in terms of both imminent mortality and prolonged periods of morbidity. They are often accompanied by unsatisfactory cosmetic as well as functional and psychological outcomes. These complications emphasise the need for stronger efforts in achieving greater diversity and effectiveness in the treatment of skin burns. This study aimed to verify the effectiveness of gross and microscopic epidermal and dermal responses in the process of regenerative repair or healing of burns in rats that were treated either daily with 5% propolis ointment or by autologous amnion graft. Second-degree burns were inflicted in the neck region of female rats by contact with a hot metal (at 130 °C) for 5 s. Propolis treatment accelerated the process of tissue repair and led to decreased local inflammation, which indicates that treatment with propolis was successful in the initial period (7 days) and stimulated the production of collagen fibre (assessed by morphometry) in all the periods evaluated (14 and 21 days). Amnion treatment inhibited local inflammation (assessed macroscopically), stimulated local epithelial regeneration (assessed microscopically) and stimulated the production of collagen fibre (assessed by morphometry) in the days following burn. These treatments offer new therapeutic strategies for treating severe skin burns; these strategies may allow the minimisation of scar formation, a more rapid return of function and, ultimately, a better quality of life for burn patients.