Clinical evaluation and induced corneal vascularization study by native and anionic collagen membranes in rabbits corneas / Avaliação clínica e estudo da vascularização corneal induzida pelas membranas de colágeno nativo e aniônico em córneas de coelhos

PURPOSE: To evaluate the corneal vascularization (CV) and the clinical aspects induced by interlamellar graft with native (NCM) and anionic (ACM) collagen membranes in rabbits corneas. METHODS: An interlamellar graft with a 0.25 x 0.25 cm NCM (group 1) or ACM (group 2) fragment was performed in the right eye (treated eye). In the left eye, an estromal tunnel was done (control eye). Sixteen rabbits were used, and they were subdivided into two experimental groups of eight animals each. The clinical evaluation was performed at the 1st, 3rd, 7th, 15th and 30th postoperative days. Corneal vascularization analysis was performed after 30 days by the Images Analizator System Leica Qwin-550®. RESULTS: After 7 days, corneal vascularization was observed at about 2.25 ± 0.71 mm (NCM) and at about 1.0 ± 1.69 mm (ACM), respectively, from the limbus in direction to the central cornea. After 15 days, CV increased in both groups (5.25 ± 1.03 mm - NCM; 2.0 ± 2.39 mm - ACM) and then progressively decreased until day 30 (2.25 ± 2.10 mm - NCM; 0.75 ± 2.12 mm - ACM). The statistical analysis indicated that the averages of the distances from the limb vessels to the grafts observed after 7 and 15 days had not differed statistically (p=0.17), and after 15 and 30 postoperative days had a tendency to differ statistically (p=0.09). The control eyes did not present any changes. CONCLUSION: The interlamellar graft with native and anionic collagen membranes induced corneal vascularization when applied to rabbit corneas, but anionic collagen membrane induced a smaller corneal vascularization when compared to native collagen membrane. Although further studies are required, the results found in this study demonstrated the usefulness of interlamellar graft with native and anionic collagen membranes in keratoplasties. These membranes consists in one more graft option for the surgical treatment of corneal repair in rabbits and others animals, when other forms of medical...

OBJETIVO: Avaliar os aspectos clínicos e vascularização corneal (VC) induzida pelo enxerto interlamelar das membranas de colágeno nativo (MCN) e de colágeno aniônico (MCA) em córneas de coelhos. MÉTODOS: Um fragmento com 0,25 x 0,25 cm de MCN (grupo 1) e MCA (grupo 2) foi realizado no olho direito (olho tratado) por enxertia interlamelar. No olho esquerdo (olho controle) foi realizado apenas um túnel estromal. No olho direito (olho controle) foi realizado apenas um túnel estromal. Dezesseis coelhos foram utilizados e foram divididos em dois grupos experimentais composto por oito animais cada. A avaliação clínica foi realizada aos 1, 3, 7, 15 e 30 dias de pós-operatório. A análise da vascularização corneal foi realizada após 30 dias pelo Sistema de analisador de imagens Leica Qwin-550®. RESULTADOS: Após 7 dias, a vascularização corneal do limbo em direção central da córnea observada foi de 2,25 ± 0,71 mm (MCN) e 1,0 ± 1,69 mm (ACM), respectivamente. Após 15 dias a vascularização corneal aumentou em ambos os grupos (5,25 ± 1,03 mm - MCN; 2,0 ± 2,39 mm - MCA), diminuindo até o 30º dia (2,25 ± 2,10 mm - MCN; 0,75 ± 2,12 mm - MCA). A análise estatística indicou que as médias das distâncias dos vasos do limbo em direção ao enxerto observadas após 7 e 15 dias não diferiram estatisticamente (p=0,17), e 15 e 30 dias de pós-operatório houve tendência a diferir estatisticamente (p=0,09). Os olhos controles não apresentaram nenhuma alteração. CONCLUSÃO: As membranas de colágeno nativo e de colágeno aniônico induzem a vascularização corneal quando aplicadas na córnea de coelhos por meio de enxertia interlamelar, mas membrana de colágeno ativo induz a pequena vascularização corneal quando comparada à membrana de colágeno aniônico. Embora estudos adicionais sejam necessários, os resultados encontrados no presente estudo demonstraram que as membranas de CN e CA possam ser úteis em ceratoplastias. Estas membranas consistem em mais uma opção de enxerto...

Clinical evaluation and induced corneal vascularization study by native and anionic collagen membranes in rabbits corneas.

PURPOSE: To evaluate the corneal vascularization (CV) and the clinical aspects induced by interlamellar graft with native (NCM) and anionic (ACM) collagen membranes in rabbits corneas. METHODS: An interlamellar graft with a 0.25 x 0.25 cm NCM (group 1) or ACM (group 2) fragment was performed in the right eye (treated eye). In the left eye, an estromal tunnel was done (control eye). Sixteen rabbits were used, and they were subdivided into two experimental groups of eight animals each. The clinical evaluation was performed at the 1st, 3rd, 7th, 15th and 30th postoperative days. Corneal vascularization analysis was performed after 30 days by the Images Analizator System Leica Qwin-550. RESULTS: After 7 days, corneal vascularization was observed at about 2.25 +/- 0.71 mm (NCM) and at about 1.0 +/- 1.69 mm (ACM), respectively, from the limbus in direction to the central cornea. After 15 days, CV increased in both groups (5.25 +/- 1.03 mm - NCM; 2.0 +/- 2.39 mm - ACM) and then progressively decreased until day 30 (2.25 +/- 2.10 mm - NCM; 0.75 +/- 2.12 mm - ACM). The statistical analysis indicated that the averages of the distances from the limb vessels to the grafts observed after 7 and 15 days had not differed statistically (p=0.17), and after 15 and 30 postoperative days had a tendency to differ statistically (p=0.09). The control eyes did not present any changes. CONCLUSION: The interlamellar graft with native and anionic collagen membranes induced corneal vascularization when applied to rabbit corneas, but anionic collagen membrane induced a smaller corneal vascularization when compared to native collagen membrane. Although further studies are required, the results found in this study demonstrated the usefulness of interlamellar graft with native and anionic collagen membranes in keratoplasties. These membranes consists in one more graft option for the surgical treatment of corneal repair in rabbits and others animals, when other forms of medical and surgical treatment are not effective.

Avaliações clínica e morfométrica da capacidade angiogênica da membrana de quitosana em córneas de coelhos / Clinical and morphometric evaluations of the angiogenic capacity of chitosan membrane in rabbit corneas

OBJETIVO: Estudar a vascularização corneal (VC) induzida pela membrana de quitosana (MQ) implantada por enxertia interlamelar na córnea de coelhos. MÉTODOS: Foram utilizados 16 coelhos. No olho esquerdo procedeu-se enxertia interlamelar de um fragmento de 0,25 x 0,25 cm de MQ (olho tratado). No olho direito realizou-se apenas a microbolsa estromal (olho controle). Avaliaram-se clinicamente os animais aos 1, 3, 7, 15 e 30 dias de pós-operatório. Aos 30 dias mensurou-se a VC pelo Sistema Analisador de Imagens LEICA QWIN-550®. RESULTADOS: Aos sete dias observou-se VC a 1,5±0,93 mm do limbo em direção ao eixo visual. Aos 15 dias houve aumento da VC (4,75±3,20 mm), que se manteve aos 30 dias (4,25±4,10 mm). Os olhos controles não apresentaram quaisquer alterações oculares. Houve diferença estatística (p<0,05) entre as áreas corneais vascularizadas dos olhos tratados e controles aos 15 e 30 dias de pós-operatório. CONCLUSÕES: A MQ induziu angiogênese corneal quando aplicada à córnea de coelhos por enxertia interlamelar, a qual persistiu de forma leve até 30 dias de pós-operatório. Embora estudos adicionais sejam necessários a MQ poderá ser mais uma opção de membrana para enxertos em ceratoplastias.

PURPOSE: To evaluate corneal vascularization (CV) induced by interlamellar graft chitosan membrane (CM) in rabbit cornea. METHODS: An interlamellar graft with a 0.25 x 0.25 cm CM fragment was performed in the left eye (treated eye). In the right eye, an estromal tunnel was done (control eye). The clinical evaluation was done at 1, 3, 7, 15 and 30 days postoperatively. CV analysis was after 30 days by the Images Analizator System LEICA QWIN-550®. RESULTS: After 7 days, CV at 1.5±0.92 mm from the limbus in direction of the cornea axial area was observed. After 15 days CV increased (4.75±3.19 mm), remaining until day 30 (4.25±4.06 mm). The control eyes did not present any changes. There was a statistical differences of the vascularizated corneal areas between control and treated eyes from the 15th to the 30th postoperative day. CONCLUSION: The chitosan membrane induced corneal angiogenesis when applied to rabbit cornea through an interlamellar graft, which was maintained at low levels until 30 days postoperatively. Although further studies are necessary, the results found here demonstrated the usefulness of chitosan membrane in keratoplasties.

[Clinical and morphometric evaluations of the angiogenic capacity of chitosan membrane in rabbit corneas]. / Avaliações clínica e morfométrica da capacidade angiogênica da membrana de quitosana em córneas de coelhos.

PURPOSE: To evaluate corneal vascularization (CV) induced by interlamellar graft chitosan membrane (CM) in rabbit cornea. METHODS: An interlamellar graft with a 0.25 x 0.25 cm CM fragment was performed in the left eye (treated eye). In the right eye, an estromal tunnel was done (control eye). The clinical evaluation was done at 1, 3, 7, 15 and 30 days postoperatively. CV analysis was after 30 days by the Image Analyzer System LEICA QWIN-550. RESULTS: After 7 days, CV at 1.5+/-0.92 mm from the limbus in direction of the cornea axial area was observed. After 15 days CV increased (4.75+/-3.19 mm), remaining until day 30 (4.25+/-4.06 mm). The control eyes did not present any changes. There was a statistical differences of the vascularizated corneal areas between control and treated eyes from the 15th to the 30th postoperative day. CONCLUSION: The chitosan membrane induced corneal angiogenesis when applied to rabbit cornea through an interlamellar graft, which was maintained at low levels until 30 days postoperatively. Although further studies are necessary, the results found here demonstrated the usefulness of chitosan membrane in keratoplasties.