Background: Gamma-ray irradiation could significantly induce widespread
apoptosis in corneas and reduced the allogenicity of donor cornea. And the X-rays may
have similar biological effects. The feasibility and effects of X-ray-irradiated corneal
lamellae have not been assessed yet.
Methods: Different doses (10 gray unit (Gy), 20 Gy, 50 Gy, 100 Gy) of X-ray irradiated
corneal lamellae were collected from SMILE surgery. These corneal lamellae were
assessed by physical characterization, hematoxylin and eosin (H-E) staining, Masson’s
staining, TdT-mediated dUTP nick end labeling (TUNEL), cell viability assay and
transmission electron microscopy (TEM). We selected the optimum dose (100Gy) to
treat the corneal lamellae to be the grafts. The human grafts and fresh allogeneic
monkey corneal lamellae were implanted into rhesus monkeys via the small incision
femtosecond laser-assisted surgery, respectively. Clinical examinations and the
immunostaining were performed after surgery.
Results: There were no significant changes in the transparency of the corneal lamellae,
but the absorbency of the corneal lamellae was increased. According to the H-E and
Masson’s staining results, irradiation had little impact on the corneal collagen. The
TUNEL assay and cell viability assay results showed that 100Gy X-ray irradiation
resulted in complete apoptosis in the corneal lamellae, which was also confirmed by
TEM observations. In the following animal model study, no immune reactions or severe
inflammatory responses occurred, and the host corneas maintained transparency for
24 weeks of observation. And the expression of CD4 and CD8 were negative in the all
Conclusion: X-ray irradiated corneal lamellae could serve as a potential material for
xenogeneic inlay, and the small incision femtosecond laser-assisted implantation has
the potential to become a new corneal transplantation surgical approach.