Corneal epithelial healing in rabbit eyes with partial corneal-conjunctival and conjunctival limbal deficiency

Cicatrização epitelial corneana em olhos de coelhos com deficiência parcial de limbo corneo-conjuntival e conjuntival

SUMMARY

Purpose:

To compare corneal epithelium healing of rabbit eyes with partial keratoconjunctival and conjunctival limbal deficiency with normal corneas (controls).

Methods:

Partial limbal deficiency (PDL) was created by surgical removal of one third of the superior limbal zone by performing a partial-thickness corneal incision at 2 mm from the limbus (Group 1) and bythe removal of conjunctival limbus without corneal dissection (Group 2). All operated eyes and control underwent two consecutive alkali burns.

Results:

Afterthe two alkali burns, the eyes ofGroup 1 had a delayed epithelial healing curve when compared with controls (p < 0.05); eyes ofGroup 2 and the controls had similar healingcurves. Corneas ofboth groups showed greater vascularization than controls but there was no significant difference. The occurrence of stromal transient opacities was greater in Group 1 when compared with controls (p < 0.05). There was only one case of permanent opacity, vascularization and persistent epithelial defects that belonged to Group 1. Cytologic evaluation showed normal epithelial corneal cells except for one case of Group 1 which showed goblet cells on the superior cornea.

Conclusions:

These results supportthe concept that in PLD corneas the epithelium is still impaired after a moderate corneal burn and that keratoconjunctival limbal removal causes a worse PLD than conjunctival limbal removal, a relatively less invasive procedure.

Keywords:
Limbal transplantation; Limbal deficiency; Chemical injuries; Stem cells

RESUMO

Objetivo:

Comparar a cicatrização epitelial corneana de olhos de coelhos com deficiência parcial de limbo (DPL) córneo-conjuntival e conjuntival com olhos normais (controles).

Métodos:

A DPL foi induzida pela retirada cirúrgica de 1/3 do limbo superior realizando uma ceratectomia a 2 mm do limbo (Grupo 1) e pela remoção do limbo conjuntival sem ceratectomia (Grupo 2). Posteriormente, todos os olhos operados e os controles foram submetidos a duas queimaduras alcalinas consecutivas.

Resultados:

Após a 1^a e 2^a queimaduras, os olhos do Grupo 1 tiveram uma curva de cicatrização epitelial significativamente mais lenta que os controles, os olhos do Grupo 2 e os contro les tiveram curvas de cicatrização similares. As córneas dos Grupos 1 e 2 apresentaram mais vascularização periférica que os controles porém sem diferença significativa. A incidência de leucomas transitórios foi maior no Grupo 1 quando comparado aos controles (p < 0.05). Houve apenas um caso de leucoma permanente, vascularização e defeito epiteliais persistentes que pertencia ao Grupo 1. A avaliação cito lógica demonstrou células epiteliais normais, com exceção de um caso do Grupo 1 que apresentou células caliciformes.

Conclusões:

Nossos resultados sustentam o conceito de que nas córneas com DPL o epitélio ainda pode estar comprometido após uma queimadura moderada e que a remoção de limbo córneo-conjuntival causa uma DPL mais grave do que a remoção de limbo conjuntival. Além disso, trata-se de um procedimento tecnicamente mais dificil e invasivo para o olho doador.

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Publication Dates

• Publication in this collection
  Oct 1998