Morphology, histology, and ultrastructure of human C31 organ-cultured corneas.

Our objective was to evaluate corneal structural modifications induced by corneal preservation in a C31 organ culture medium. Twenty-four postmortem human corneas preserved in C31 medium (CRTS, Besançon, France) for 2-21 days and 12 fresh postmortem human corneas were studied and evaluated by means of light microscopy, morphometry, and transmission electron microscopy (TEM). Endothelial cell loss during preservation averaged 9.2% (+/- 7.2%). Endothelial morphology displayed significantly more moderate alterations in the group of fresh corneas than in the group of preserved corneas. Endothelial morphometry resulted in a higher coefficient of variation (p = 0.002) in the preserved group but showed no difference for the average figure coefficient and average cell area. The histological study showed corneal swelling and epithelial sloughing in the preserved group. TEM displayed moderate preservation injuries, such as numerous vacuoles, mitochondrial swelling, and increased cell thickness. These results are consistent with previous findings that indicated that C31 medium induces moderate preservation injuries.

Modulation of HLA-DR and CD1a expression on human cornea with low-dose UVB irradiation.

PURPOSE: To evaluate the effects of low-dose UVB irradiation of HLA and CD1a expression and the toxic effects of UVB on human corneas. METHODS: 24 pairs of human corneas from 24 donors were studied. One cornea from each pair was randomly irradiated with UVB (100 mJ/cm2) after enucleation. All corneas were then organ-cultured for 2, 7, 14 or 21 days. Endothelium was studied after enucleation and organ culture. Following preservation, corneas were evaluated by means of light microscopy, morphometry and TEM. HLA and CD1a staining was performed using an immuno-alkaline-phosphatase technique. RESULTS: Endothelial cell loss during organ culture averaged 9.1% in the UVB group and 9.2% in the control group (NS). The number of rosette and reformation figures (p = 0.004) and the coefficient of variation (p = 0.014) were higher in the control group. Epithelial sloughing was more accentuated in the UVB group. We observed the same moderate ultrastructural injuries in both groups. In the epithelium, the average number of HLA-DR+ cells per field was 0.12 in the UVB group and 0.42 in the control group (p = 0.035). In the stroma, these figures were respectively 1.04 and 1.34 (p = 0.026). In the epithelium, the average number of CD1a + cells was respectively 0. 025 and 0.078 (p = 0.019). In the preservation mediums, the average percentage of CD1a + cells was 0.07% in the UVB group and 0.27% in the control group (p = 0.014). CONCLUSIONS: Low-dose UVB (100 mJ/cm2) decreases HLA-DR and CD1a expression of organ-cultured human corneas and induces moderate corneal injuries. Low-dose UVB might be useful for preventing allograft rejection.