Stromal architecture and immune tolerance in additive corneal xenografts in rodents

Abstract

ABSTRACT.Purpose: To examine immune tolerance and corneal ultrastructure following additive corneal xenografts in rodents. Methods: We carried out surgical implantation of excised BALB/c mouse corneal tissue, either freshly isolated (n = 6) or after storage at -20 C for 1 week (n = 7), into the corneas of Wistar rats at approximately mid-stromal depth. Corneal opacity and neovascularization were evaluated postoperatively, and stromal ultrastructure was observed by transmission electron microscopy. Results: Corneal opacification and neovascularization in the weeks after surgery were less prevalent in grafts of frozen-then-thawed tissue than in grafts of fresh tissue. In a well tolerated frozen-then-thawed xenograft, the matrix architecture was normal throughout most of the recipient and donor tissue, but pronounced fibrillar disorganization was evident adjacent to Descemet's membrane. Conclusion: We attribute the improved tolerance of frozen-then-thawed xenografts over fresh xenografts to a reduced cellular immune response.

Processing Porcine Cornea for Biomedical Applications

“…16 Second, the ECM, composed mainly of collagen and representing >70% of the dry weight of the cornea, is essential for corneal transparency because of the regular arrangement of uniformly thin collagen fibrils into lamellae. 17,18 Therefore, much effort has been expanded to develop efficient ECM for tissue-engineered corneal equivalents, although none has been clinically usable. 2,3 Thus, we believed that pig corneal stroma, which has physical and refractive properties similar to those seen in human corneas, 6 would be a good ECM substitute for human corneas with defects or opacities.…”

Survival and integration of tissue-engineered corneal stroma in a model of corneal ulcer

“…After 2, 4, 16, and 32 weeks, each treated eye was examined by using slit-lamp microscopy and photographed for changes of transparency and neovascularization. To evaluate the recovery of the cornea, the data were recorded according to the scoring criteria of Quantock et al (2005) regarding transparency (0=cornea clear, 1=moderate corneal opacity, 2=severe corneal opacity) and neovascularization (0=no vessels, 1=moderate neovascularization only in recipient cornea, 2=severe neovascularization in graft tissue). At specific time points, rabbits were anesthetized with an overdose of sodium pentobarbital, and the cornea from each was harvested immediately.…”