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Master's Dissertation
DOI
https://doi.org/10.11606/D.10.2020.tde-11022020-101437
Document
Author
Full name
Murillo Martinez Matheus
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Pirassununga, 2019
Supervisor
Committee
Corrêa, Rodrigo Romero (President)
Blazquez, Francisco Javier Hernandez
Foz Filho, Roberto Pimenta de Pádua
Title in Portuguese
Influência da degradação tempo-dependente e do processo de congelamento e descongelamento sobre as características histológicas e biomecânicas do jejuno de bovinos hígidos
Keywords in Portuguese
Conservação intestinal
Criopreservação
Ensaio biomecânico
Histologia
Intestino delgado
Abstract in Portuguese
A degradação do intestino delgado de bovinos sadios, bem como seu efeito sobre a resistência biomecânica, não são descritos na literatura. Trabalhos que envolveram a biomecânica intestinal realizaram os ensaios em poucas horas após o óbito dos doadores, sem avaliação de seu estado de deterioração. O congelamento é eficiente na conservação de vários tecidos, porém, pode provocar danos ao nível celular nos tecidos ricos em água. Este estudo teve por objetivo avaliar a degradação morfológica e biomecânica do jejuno de bovinos em diferentes tempos post mortem, bem como o efeito do congelamento e descongelamento sobre estas características. Foram coletados segmentos de jejuno de seis animais, e fragmentos destes segmentos foram fixados em formol em diferentes tempospost morten (0, 2, 4, 6, 8, 12, 18, 24, 36, 48 horas) para avaliação histológica. Em outra fase, mais 20 segmentos foram coletados e submetidos a teste biomecânico em diferentes tempos post morten (0, 4, 6, 8, 12, 18, 24, 36, 48 horas), além do mesmo teste após congelamento e descongelamento. As primeiras alterações macroscópicas foram observadas com oito horas após o óbito. Mesmo momento em que surgiram os primeiros sinais de lesão estrutural ao exame histológico. Este também foi o momento de menor pressão suportada ao teste biomecânico. A partir de 12 horas o tecido sofreu rearranjo estrutural, voltando a suportar maior pressão, seguida de queda gradual após 18 horas. As lesões histológicas se apresentaram de maneira progressiva e gradual. As amostras testadas após descongelamento não apresentaram diferença estatística quanto à resistência mecânica em comparação com os espécimes frescos. Independente do aspecto morfológico, as amostras de todos os tempos, assim como as descongeladas, apresentaram resistência muito superior às consideradas fisiológicas ou patológicas.
Title in English
Degradation time-dependent, freezing and thawing influence on histological and biomechanical characteristics of healthy cattle jejunum
Keywords in English
Biomechanical essay
Cryopreservation
Histology
Intestinal conservation
Small intestine
Abstract in English
The degradation of the small intestine of healthy cattle, as well as its effect on biomechanical resistance are not described in the literature. Studies involving intestinal biomechanics perform tests within hours of donor death, without evaluating its deterioration state. Freezing is effective in conserving various tissues, but can cause cellular damage to water-rich tissues. This study aimed to evaluate the morphological and biomechanical degradation of the bovine jejunum at different post mortem times, as well as the effect of freezing and thawing on these characteristics. Jejunum segments were collected from six animals, and fragments of these segments were fixed in formaldehyde at different post morten moments (0, 2, 4, 6, 8, 12, 18, 24, 36, 48 hours) to histologic evaluation. In another phase, 20 other segments were collected and submitted to biomechanical testing at different post morten times (0, 4, 6, 8, 12, 18, 24, 36, 48 hours) beyond the same test after freezing and thawing. The first macroscopic changes were observed at eight hours after death. The same time that the first signs of structural damage appeared at the histological examination. This was also the moment of least pressure supported by the biomechanical test. Within12 hours the tissue was rearranged again to withstand greater pressure, which gradually decreased after 18 hours. The histological lesions were progressive and gradual. Samples tested after thawing showed no statistical difference in mechanical strength compared to fresh specimens. Regardless of the degree of morphological aspect, samples time, as well as thawed ones, all of them presented resistance higher than those considered physiological or pathological.
 
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Publishing Date
2020-04-23
 
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