Age-related degeneration of the equine endometrium is an established and important cause of fertility problems in thoroughbred mares, causing great loss to the industry. As a part of the age-related endometrial degeneration complex, an excessive deposition of collagen leading to endometrial fibrosis is particularly important due to the limitations it causes to uterine function. The consequences include reduced efficacy of uterine defence mechanisms and a decrease in the uterine capacity for foetal nutrition. Extensive research into the process of fibrosis in other organs has shown that this condition results from the malfunction of physiological tissue repair mechanisms. These mechanisms revolve around tissue fibroblasts that due to continuous stimulation secrete excessive amounts of collagen and inhibit the activation of factors essential to the normal collagen degradation occurring in scar resolution. Among these factors are the MMPs, an enzyme family with the ability to degrade extracellular matrix components such as collagen during the normal repair mechanisms following tissue injury. The malfunction in the regulation of these enzymes is important in the development of fibrosis in the liver and other organs. In this study it was demonstrated that MMPs are involved in the acute uterine inflammatory response and that they were secreted by infiltrating inflammatory cells. The cellular mechanisms observed during endometritis in normal mares were comparable to the normal repair mechanisms known to be altered in the fibrosis of other organs. These enzymes were present in equine foetal fluids, and their regulation may be important in the process of abortion and stillbirth. It was demonstrated that inbreeding may be correlated with increased deposition of endometrial collagen in a study population of the Icelandic horse breed even though this breed appears to exhibit less severe endometrial degeneration than what is known in lighter breeds. It is likely that genetic predisposition leads to the disruption of normally self-limiting inflammatory and repair mechanisms in the endometrium, resulting in constant activation of collagen synthesis by local and infiltrating cells. This thesis has shown that tissue repair mechanisms involving MMPs are likely to be involved in endometrial fibrosis in the mare. An inherent alteration in these mechanisms may play a role in the pathogenesis of this condition, and might arise due to genetic predisposition. Further understanding of the pathways leading to excess collagen amounts in the endometrium may produce preventative measures, and even therapeutic targets.

Orientador: Julio Lopes Sequeira / Banca: Alessandre Hataka / Banca: Noeme Sousa Rocha / Resumo: O presente trabalho teve por objetivos avaliar os graus de fibrose endometrial das éguas, especificando por técnicas histoquímicas os tipos de colágeno e sua proporção nas lesões crônicas, além de verificar por método imunoistoquímico a expressão e distribuição das metaloproteinases (MMP) 2 e 9 e um dos seus inibidores - TIMP-1 - nos processos crônicos endometriais. Foram utilizadas 82 biópsias endometriais classificadas histologicamente de acordo com Kenney e Doig (1986) e segundo as definições de Ricketts & Alonso (1991) para endometrite crônica infiltrativa e endometrose. A avaliação do colágeno foi realizada pelos métodos histoquímicos Tricrômico de Masson, Reticulina e Picrosirius Red. Estudo morfométrico da fibrose periglandular foi realizado utilizando-se a técnica histoquímica do Picrosirius Red. Os resultados mostraram que nos endométrios portadores de endometrite severa há deposição de colágeno do tipo III e do tipo I, sendo este predominante. Não houve diferença significativa na extensão da fibrose periglandular entre as endometrites crônicas infiltrativas e endometroses. Tanto no endométrio hígido como nas endometrites crônicas foi observada imuno-reatividade para as enzimas estudadas. A reação imunoistoquímica para MMP-2 foi localizada no epitélio luminal, glandular, parede vascular e células estromais. MMP-9 e TIMP-1 mostraram marcação mais difusa, sendo também observadas nas células inflamatórias e endoteliais. / Abstract: The aim of this study was to evaluate the degrees of endometrial fibrosis in mares, specifying the types of collagen in the chronical lesions and its ratio by histochemical analysis and, the expression and distribution of matrix metalloproteinases (MMP) 2, -9 and one of its inhibitors - TIMP-1 - in the endometrial chronic processes by means of immunohistochemistry. Eighty-two biopsies of chronic endometritis were classified according to Kenney and Doig (1986) and definitions of Ricketts & Alonso (1991) for chronic infiltrative endometritis and endometrosis. The collagen evaluation was made by Massonþs trichrome, Reticulin and Picrosirius Red staining methods. The endometrial periglandular fibrosis morfometric analysis was carried out by using Picrosirius Red stained slides. Deposition of type III collagen and type I collagen was seen in severe endometritis with type I predominance. The chronic infiltrative endometritis and endometrosis didn't show significant difference in the extension of periglandular fibrosis. Immunoreactivity of MMP-2, MMP-9 and TIMP-1 was detected in healthy endometrium as in severe chronic endometritis. The luminal epithelium, glandular epithelium, vascular wall and stromal cells expressed MMP-2. MMP-9 and TIMP-1 had shown diffuser marking, and were as well observed in the inflammatory cells and the endothelium. / Mestre

Made available in DSpace on 2014-06-11T19:23:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-03-03Bitstream added on 2014-06-13T18:51:23Z : No. of bitstreams: 1 porto_cd_me_botfmvz.pdf: 1148582 bytes, checksum: e1e5d2ae85a99623d360346e60e58058 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente trabalho teve por objetivos avaliar os graus de fibrose endometrial das éguas, especificando por técnicas histoquímicas os tipos de colágeno e sua proporção nas lesões crônicas, além de verificar por método imunoistoquímico a expressão e distribuição das metaloproteinases (MMP) 2 e 9 e um dos seus inibidores - TIMP-1 - nos processos crônicos endometriais. Foram utilizadas 82 biópsias endometriais classificadas histologicamente de acordo com Kenney e Doig (1986) e segundo as definições de Ricketts & Alonso (1991) para endometrite crônica infiltrativa e endometrose. A avaliação do colágeno foi realizada pelos métodos histoquímicos Tricrômico de Masson, Reticulina e Picrosirius Red. Estudo morfométrico da fibrose periglandular foi realizado utilizando-se a técnica histoquímica do Picrosirius Red. Os resultados mostraram que nos endométrios portadores de endometrite severa há deposição de colágeno do tipo III e do tipo I, sendo este predominante. Não houve diferença significativa na extensão da fibrose periglandular entre as endometrites crônicas infiltrativas e endometroses. Tanto no endométrio hígido como nas endometrites crônicas foi observada imuno-reatividade para as enzimas estudadas. A reação imunoistoquímica para MMP-2 foi localizada no epitélio luminal, glandular, parede vascular e células estromais. MMP-9 e TIMP-1 mostraram marcação mais difusa, sendo também observadas nas células inflamatórias e endoteliais. / The aim of this study was to evaluate the degrees of endometrial fibrosis in mares, specifying the types of collagen in the chronical lesions and its ratio by histochemical analysis and, the expression and distribution of matrix metalloproteinases (MMP) 2, -9 and one of its inhibitors - TIMP-1 - in the endometrial chronic processes by means of immunohistochemistry. Eighty-two biopsies of chronic endometritis were classified according to Kenney and Doig (1986) and definitions of Ricketts & Alonso (1991) for chronic infiltrative endometritis and endometrosis. The collagen evaluation was made by Massonþs trichrome, Reticulin and Picrosirius Red staining methods. The endometrial periglandular fibrosis morfometric analysis was carried out by using Picrosirius Red stained slides. Deposition of type III collagen and type I collagen was seen in severe endometritis with type I predominance. The chronic infiltrative endometritis and endometrosis didn't show significant difference in the extension of periglandular fibrosis. Immunoreactivity of MMP-2, MMP-9 and TIMP-1 was detected in healthy endometrium as in severe chronic endometritis. The luminal epithelium, glandular epithelium, vascular wall and stromal cells expressed MMP-2. MMP-9 and TIMP-1 had shown diffuser marking, and were as well observed in the inflammatory cells and the endothelium.