Abstract
Purpose: :
To investigate the effect of human immature dental pulp stem cells (hIDPSC) transplantation for ocular surface reconstruction in an animal model of total limbal stem cells deficiency (TLSCD) secondary to chemical injury.
Methods: :
An animal model of TLSCD was induced by chemical burn with NaOH 0.5M applied in one eye of male rabbits either for 45 seconds (SCB - severe chemical burn) (n=6) or for 25 seconds (MCB - mild chemical burn) (n=6). After 1.5 months, a superficial keratectomy was performed. Human IDPSC, which had been cultivated without 3T3 feeder, were transplanted without previous differentiation to the corneal bed and then covered with a patch of human amniotic membrane (AM). In the control group, the animals received only AM. After 3 months, a detailed clinical evaluation of the rabbits' eyes was performed. The animals were then sacrificed and the corneas were submitted to histological, ultra-structural, and immunohistochemical study. To assess the differentiation of the hIDPSC, antibodies (AB) against different epithelial antigens and hIDPSC were used. Cy3 anti-mouse AB was used as the secondary AB.
Results: :
Corneal transparency of the eyes which underwent hIDPSC transplantation was improved throughout the follow-up. Rabbits from MCB group presented much clearer corneas with less neovascularization than those from SCB and control groups. The control animals’ corneas developed total conjunctivalization and opacification. Histological analysis showed uniform corneal epithelium over the corneal stroma in MCB eyes; corneal and conjunctival epithelium in SCB eyes; and only conjunctival epithelium in control eyes. The presence of hIDPSC was detected in both MCB and SCB animals and the differentiation into corneal epithelium was proven through positive staining for corneal epithelial cell markers. Interestingly, we also observed positive hIDPSC infiltrating the corneal stroma. MCB and SCB rabbits showed the same pattern of staining. Control animal did not present corneal epithelium formation.
Conclusions: :
Our results suggest that hIDPSC transplanted to the eyes of a rabbit in TLSCD have the ability to differentiate into corneal epithelium after both mild and severe chemical burns. The former presented better clinical outcomes than the latter. We believe that severely chemically burnt corneas may benefit from hIDPSC.
Keywords: cornea: basic science • cornea: epithelium