Abstract:
Introduction. Thanks to its regenerative properties, the human amniotic membrane (AM) is
extensively used in ophthalmology to treat a wide range of eye surface conditions. Despite the vast
amount of studies justifying its ophthalmic use, there is lacking scientific data on the effectiveness
of differently processed AM in the treatment of corneal ulcers. In this paper, we aim to compare the
effectiveness of cryopreserved, lyophilized and decellularized amniotic membrane transplantation
(AMT) in the management of corneal ulcers in a rabbit model.
Material and methods. Corneal ulcers were surgically induced in the left eyes of 28 rabbits. Four
groups, each containing 7 specimens, were formed: group A (control) – rabbits treated
conservatively, with no AMT; group B – rabbits operated with cryopreserved AM; group C –
rabbits operated with decellularized AM; and group D – rabbits operated with lyophilized AM. The
rabbits were clinically observed for a 3-month period, with the assessment of objective signs, the
evolution of the corneal lesion and/or complications. After the follow-up period, the rabbits were
euthanized; the left corneas were excised, fixed in 10% formaldehyde and then embedded in
paraffin, cut into thin sections, stained with hematoxylin-eosin, and studied by light microscopy.
Results. The cornea regenerated the slowest in the control group (28 days), the fastest in group B
(15 days), followed by group D (18 days) and then group C (21 days). The highest rate of infectious
complications was found in rabbits from group A (57%, n=4), and the lowest – in the group
operated with cryopreserved AM (14%, n=1). Corneal neovascularization and opacification were
most intense in the control group. In the groups operated with AM, corneal transparency was
relatively uniformly recovered, with a slightly poorer outcome in the group C. In conservatively
treated corneas (A), histological examination revealed a thickened and deformed epithelium, patchy
connective tissue and epithelial cell depletion; in corneas treated with cryopreserved AM (B),
fibroblast proliferation and solitary lymphocytic infiltrate below Bowman's membrane were
revealed; in corneas treated with decellularized (C) and lyophilized (D) AM, polymorphic and
atrophied epitheliocytes were found.
Conclusion. While there were significant differences between the control group and the eyes
treated with AMT, the clinical signs did not differ significantly between groups operated with
cryopreserved, decellularized and lyophilized AM. Still, the cryopreserved AM showed the best
results in terms of post-operative complications, regenerative capacities and restoration of corneal
transparency.
