MORPHOLOGICAL CHANGES IN THE EQUIVALENT OF THE CORNEA STROMA OBTAINED BY THE DECELULARIZATION METHOD

Abstract

Introduction. Diseases and injuries of the cornea are a major cause of vision impairment and blindness. Currently, the best treatment for restoring vision in patients with corneal blindness is transplantation with donor-derived corneal tissue.  Decellularized corneas are among the most promising materials for engineering corneal tissue since they replicate the complex structure and composition of real corneas. Decellularization is a process that aims to remove cells from organs or tissues resulting in a cell-free scaffold consisting of the tissues extracellular matrix. Due to the deficiency of the donor human cornea and the low efficiency of its transplantation in some types of corneal pathology, the search for alternative materials for keratoplasty is relevant, which has stimulated the search for different methods of manufacturing and using xeogenic grafts.

The aim of the study – to learn the morphofunctional changes of the equivalent of the stroma of the cornea, removed from the eyes of pigs and obtained by the method of decelularization in order to further its use as a material for keratoplasty.

Research Methods. The corneal membrane obtained from the removed eyes of pigs is placed in a tissue culture medium, after which it is decelerized. Treated with 0.5 % solution of sodium dodecyl sulfate with constant shaking; treated with ultrasound (three times), incubate in the presence of an enzyme solution of papain; washed with buffer solution (pH 6.5), centrifuged. Place in a solution of polyvinylpyrrolidone for storage.

Results and Discussion. The morphofunctional state of the equivalent of the corneal stroma obtained by the method of decelularization was studied. Microscopically in histological preparations of the equivalent of the corneal stroma obtained by the method of decelularization, the destruction of the anterior and posterior epithelium of the cornea is detected. The surface of its own substance is limited by a dense anterior border plate (Bowman's membrane), there are remnants of multilayered squamous non-keratinized epithelium. Histological examinations showed that the homogeneity of its structure is lost in the corneal's own substance, the connective tissue plates are stratified, and the corneal's own substance acquires a reticular appearance. In some areas of the histological section of the decelularized cornea in the spaces between the bundles of collagen fibrils of its own substance, destructively altered oblong fibroblasts are microscopically observed, their nuclei are intensely basophilic, the cytoplasm is not contoured.

Conclusion. Thus, it is histologically established that the decelularization of the cornea leads to significant changes in its morphological state, associated with the destruction of the cellular component of epithelial tissues and the defibering of collagen bundles of substantia propria with the formation of a network. These microscopic changes indicate that the use of developed technique of decelularization is effective to obtain the equivalent of the xenocorneal stroma for transplantation. Further development and improvement of these methods, wider introduction into clinical practice is one of the most relevant and promising areas of ophthalmotransplantology.