Biocompatibility of Nanocomposites Used for Artificial Conjunctiva: In Vivo Experiments

Abstract

Purpose: To evaluate the biocompatibility of nanocomposites used for artificial conjunctiva. Methods: Fifty New Zealand white rabbits were used for the experiments. Nanocomposites of poly ϵ-caprolactone (PCL) and of PCL coated with polyvinyl alcohol (PCL+PVA), polyvinyl pyrrolidone (PCL+PVP), or chitosan (PCL+C), and amniotic membrane (AM) as a control, were cut into small disks with a diameter of 3.5 mm. The disks were inserted underneath the conjunctiva to measure their inflammation-inducing properties. To investigate epithelial adhesion and goblet cell differentiation, the disks were transplanted after round conjunctival excision. Cultivated conjunctival epithelial cells on nanocomposite were then transplanted onto the abdomen of Balb/c athymic mice. The number of inflammatory cells and the density of goblet cells were measured using hematoxylin and eosin, periodic-acid–Schiff, and immunohistochemistry after 2 weeks. Results: The number of inflammatory cells found inside of the inserts was as follows: 21 ± 4.9 for controls, 21 ± 15.1 for PCL, 49.6 ± 26.0 for PCL+PVP, 40.2 ± 17.1 for PCL+C, and 13.8 ± 3.9 for PCL+PVA. In PCL+PVA, the accumulation of inflammatory cells was significantly lower than in the controls (p < 0.01, Mann-Whitney U). The reepithelialization of conjunctival cells was accomplished in more than 75% of all disks except for the PCL+C. In addition, we found the differentiation of goblet cells in the following order from greatest to least: amniotic membrane, PCL, and PCL+PVP. Conclusions: Nanocomposites of PCL were biocompatible in rabbit conjunctiva, suggesting that PCL may be considered as a candidate for use in the development of artificial conjunctiva.