Modelos de neovascularização corneana em coelhos: análise morfológica
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Data
2003-10-01
Autores
Parente, Daniel Ramos [UNESP]
Silva, Maria Rosa Bet de Moraes [UNESP]
Silva Júnior, Raimundo Gerônimo da
Marques, Mariângela Esther Alencar [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Conselho Brasileiro de Oftalmologia
Resumo
OBJETIVOS: Comparar em coelhos três modelos experimentais de destruição das células germinativas (CG) do limbo corneano quanto a aspectos morfológicos. MÉTODOS: Foram utilizados 54 coelhos, 108 olhos, subdivididos em 3 grupos experimentais: (G1), (G2) e (G3), formados por 18 coelhos cada, que tiveram o OE submetido às técnicas experimentais (T1), (T2) e (T3), respectivamente, e um grupo controle, formado por 54 olhos contralaterais (OD) dos coelhos do G1, G2 e G3. Quatro parâmetros morfológicos foram estudados: epitélio, resposta inflamatória, vascularização e resposta fibroblástica. RESULTADOS: Com a T1 não houve remoção da totalidade do epitélio límbico, com a T2 houve remoção da quase totalidade do epitélio límbico, com a T3 houve remoção da totalidade do epitélio límbico. A reparação da superfície corneana foi feita por epitélio de fenótipo conjuntival (conjuntivalização) com as três técnicas, havendo aparecimento de células caliciformes a partir do 14º dia, sendo a densidade maior no 28º dia. A resposta inflamatória com a T3 foi mais intensa que com a T1 e T2. A regressão foi mais rápida com a T1 e similar com a T2 e T3. Contribuiu para a turvação corneana principalmente no 14º e 28º dia, concentrando-se, principalmente, na metade estromal anterior, sendo poupada a metade posterior. Foi maior até o 28º dia, decrescendo a partir desse momento. Caracterizou-se, no início, por infiltrado com predomínio de polimorfonucleares e sofreu mudança no 56º dia para infiltrado com predomínio de mononucleares. Os neovasos apareceram a partir do 7º dia, a princípio permearam o estroma do terço médio para cima, progredindo para a superficialização com a regressão do edema estromal. A vascularização com as três técnicas, ao final do experimento, foi superficial no estroma, porém não houve a formação de tecido fibro-escleroso denso ou cicatriz propriamente dita distinta do estroma corneano. CONCLUSÕES: Ocorreu conjuntivalização e neovascularização nas três técnicas experimentais. As T2 e T3 mostraram-se adequadas como possíveis modelos de ampla remoção das CG límbicas, levando a resultados similares nos diversos parâmetros estudados. A T1 se mostrou adequada como modelo de remoção parcial do epitélio límbico.
PURPOSE: To compare three experimental models of limbal stem cell (SC) removal in rabbits in relation to morphologic aspects. METHODS: In the present study, 54 rabbits (108 eyes) were divided into 3 experimental groups - (G1), (G2) and (G3). Each group consisted of 18 rabbits whose left eyes were submitted to 3 different experimental techniques - (T1), (T2) and (T3), respectively. A control group was formed with the 54 remaining eyes (RE) of the G1, G2 and G3 rabbits. Four morphological parameters were assessed: epithelium, inflammatory response, vascularization and fibroblastic response. RESULTS: The limbal epithelium was not completely removed by T1, was almost totally removed by T2, and thoroughly removed by T3. Corneal surface was healed by conjunctival phenotype (conjunctivalization) in the three groups. Goblet cells started to appear on days 14 and their density peaked on day 28. The inflammatory response was more intense in G3 than in G1 and G2. Regression was faster in G1 and similar in G2 and G3 contributing to corneal opacity specially on days 14 and 28. It was mainly concentrated at the stromal anterior half, whereas the posterior half was spared. It peaked on day 28 and decreased from that moment on. In the beginning, it was characterized by a predominantly polymorphonuclear infiltrate, which, on day 56, changed to mononuclear. The new vessels started appearing on days 7. At first, they permeated the stromal upper half and progressed toward the surface as the stromal edema decreased. In the three groups, at the end of the experiment, vascularization was superficial in the stroma; but no thick sclerotic-fibrous tissue nor actual scars, distinct from the corneal stroma, were formed. CONCLUSIONS: Conjunctivalization and neovascularization occurred in all experimental models. T2 and T3 seemed to be adequate models for the removal of limbal SC and most studied parameters showed similar results. T1 was found to be an adequate model for the partial-thickness removal of limbal SC.
PURPOSE: To compare three experimental models of limbal stem cell (SC) removal in rabbits in relation to morphologic aspects. METHODS: In the present study, 54 rabbits (108 eyes) were divided into 3 experimental groups - (G1), (G2) and (G3). Each group consisted of 18 rabbits whose left eyes were submitted to 3 different experimental techniques - (T1), (T2) and (T3), respectively. A control group was formed with the 54 remaining eyes (RE) of the G1, G2 and G3 rabbits. Four morphological parameters were assessed: epithelium, inflammatory response, vascularization and fibroblastic response. RESULTS: The limbal epithelium was not completely removed by T1, was almost totally removed by T2, and thoroughly removed by T3. Corneal surface was healed by conjunctival phenotype (conjunctivalization) in the three groups. Goblet cells started to appear on days 14 and their density peaked on day 28. The inflammatory response was more intense in G3 than in G1 and G2. Regression was faster in G1 and similar in G2 and G3 contributing to corneal opacity specially on days 14 and 28. It was mainly concentrated at the stromal anterior half, whereas the posterior half was spared. It peaked on day 28 and decreased from that moment on. In the beginning, it was characterized by a predominantly polymorphonuclear infiltrate, which, on day 56, changed to mononuclear. The new vessels started appearing on days 7. At first, they permeated the stromal upper half and progressed toward the surface as the stromal edema decreased. In the three groups, at the end of the experiment, vascularization was superficial in the stroma; but no thick sclerotic-fibrous tissue nor actual scars, distinct from the corneal stroma, were formed. CONCLUSIONS: Conjunctivalization and neovascularization occurred in all experimental models. T2 and T3 seemed to be adequate models for the removal of limbal SC and most studied parameters showed similar results. T1 was found to be an adequate model for the partial-thickness removal of limbal SC.
Descrição
Palavras-chave
Limbo da córnea, Células germinativas, Epitélio da córnea, Células-tronco, Neovascularização da córnea, Coelhos, Limbus corneae, Germ cells, Epithelium corneal, Stem cells, Corneal neovascularization, Rabbits
Como citar
Arquivos Brasileiros de Oftalmologia. Conselho Brasileiro de Oftalmologia, v. 66, n. 5, p. 659-666, 2003.