Modelos experimentais de deficiência limbar em coelhos: análise clínica
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Data
2002-03-01
Autores
Parente, Daniel Ramos [UNESP]
Silva, Maria Rosa Bet de Moraes [UNESP]
Silva Júnior, Raimundo Gerônimo da [UNESP]
Marques, Mariângela Esther Alencar [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Conselho Brasileiro de Oftalmologia
Resumo
Objetivo: Comparar em coelhos três modelos experimentais de destruição das células germinativas (CG) do limbo corneano quanto a aspectos clínicos. Métodos: Foram utilizados 54 coelhos, 108 olhos, subdivididos em 3 grupos experimentais: (G1), (G2) e (G3), cada um formado pelos OE de 18 coelhos, submetidos às técnicas experimentais (T1), (T2) e (T3), respectivamente, e um grupo controle, formado pelos 54 olhos contralaterais (OD). Nas três técnicas foi utilizado o n-heptanol. Na T1, o n-heptanol foi aplicado por 5 minutos, para remoção do epitélio límbico. Na T2, além da aplicação do n-heptanol, realizou-se peritomia e remoção da conjuntiva perilímbica até 4 mm do limbo, juntamente com a escarificação do tecido episcleral. Na T3, além dos procedimentos da T2, foi realizada dissecção lamelar do limbo abrangendo aproximadamente 1,5 mm na periferia da córnea e 2 mm na superfície escleral. em todas as córneas dos animais foram estudados seis parâmetros clínicos: neovascularização, perda da transparência, irregularidade da superfície, reparação epitelial, erosão ou defeito epitelial, granuloma e outras lesões corneanas. Resultados: A neovascularização corneana iniciou-se mais precocemente com a T1 e T2; ocorreu em 100% dos casos com as três técnicas, de forma não homogênea, variando de leve a intensa; permaneceu estável a partir do 28º dia até o final do experimento (56º dia), foi maior nos quadrantes superior e inferior e menor nos quadrantes nasal e temporal. A perda da transparência e a irregularidade da superfície corneana foram menores com a T1 que com a T2 e T3, que foram similares entre si. Houve, nas três técnicas experimentais, latência de três dias para o início da reepitelização, que se completou com a T1 no 7º dia e com a T2 e T3 no 14º dia. Erosão epitelial corneana e granuloma corneano foram encontradas de forma similar nas três técnicas experimentais. Conclusões: A 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. Ocorreu conjuntivalização e neovascularização nas três técnicas experimentais.
Purpose: To compare the clinical aspects of three experimental models of limbal stem cell (SC) deficiency in rabbits. 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. The 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). In all 3 techniques n-heptanol was used. In T1, the epithelium was removed by applying n-heptanol for 5 minutes. In T2, the n-heptanol application was followed by a 360º conjunctival peritomy at 4 mm beyond the limbus and scraping of the episcleral tissue. In T3, besides the procedure followed in T2, a lamellar dissection towards the limbus was performed, including 1.5 mm of the peripheral cornea and 2 mm of the scleral surface. Six clinical parameters of the corneas were studied: neovascularization, opacity, surface irregularity, epithelial wound healing, epithelial erosion, presence of granuloma and other injuries. Results: Corneal neovascularization started earlier in G1 and G2. It occurred heterogeneously, ranging from mild to intense, in 100% of the cases. It remained stable from the 28th day up to the end of the experiment (56th day). It was more intense in the upper and lower corneal quadrants and less intense in the nasal and temporal quadrants. Corneal opacity and irregularity of the corneal surface were less intense in G1 than in G2 and G3, which were similar. Reepithelialization started after a 3-day latency period in all the animals submitted to the three experimental techniques and was complete on day 7 in G1 and day 14 in G2 and G3. The rate of occurrence of corneal epithelial erosion and corneal stromal granuloma were similar in the 3 groups. Conclusions: T2 and T3 seemed to be suitable experimental models for total limbal stem cell deficiency and most of the parameters showed similar results. T1 was found to be an appropriate model for the partial-thickness removal of limbal SC. Conjunctivalization and neovascularization occurred in all experimental models.
Purpose: To compare the clinical aspects of three experimental models of limbal stem cell (SC) deficiency in rabbits. 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. The 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). In all 3 techniques n-heptanol was used. In T1, the epithelium was removed by applying n-heptanol for 5 minutes. In T2, the n-heptanol application was followed by a 360º conjunctival peritomy at 4 mm beyond the limbus and scraping of the episcleral tissue. In T3, besides the procedure followed in T2, a lamellar dissection towards the limbus was performed, including 1.5 mm of the peripheral cornea and 2 mm of the scleral surface. Six clinical parameters of the corneas were studied: neovascularization, opacity, surface irregularity, epithelial wound healing, epithelial erosion, presence of granuloma and other injuries. Results: Corneal neovascularization started earlier in G1 and G2. It occurred heterogeneously, ranging from mild to intense, in 100% of the cases. It remained stable from the 28th day up to the end of the experiment (56th day). It was more intense in the upper and lower corneal quadrants and less intense in the nasal and temporal quadrants. Corneal opacity and irregularity of the corneal surface were less intense in G1 than in G2 and G3, which were similar. Reepithelialization started after a 3-day latency period in all the animals submitted to the three experimental techniques and was complete on day 7 in G1 and day 14 in G2 and G3. The rate of occurrence of corneal epithelial erosion and corneal stromal granuloma were similar in the 3 groups. Conclusions: T2 and T3 seemed to be suitable experimental models for total limbal stem cell deficiency and most of the parameters showed similar results. T1 was found to be an appropriate model for the partial-thickness removal of limbal SC. Conjunctivalization and neovascularization occurred in all experimental models.
Descrição
Palavras-chave
Células germinativas, Limbo da córnea, Modelos animais, Coelhos, Germ cells, Limbus corneal, Models, animal, Rabbits
Como citar
Arquivos Brasileiros de Oftalmologia. Conselho Brasileiro de Oftalmologia, v. 65, n. 2, p. 153-160, 2002.