Collagen matrix in conjunctival reconstruction: evaluation of morphofunctional results in vivo

Relevance Pathological conditions associated with conjunctival damage occur with the proliferation of fibrous tissue, scarring of the fornices and their shortening, which can lead to the development of erosions and ulcers of the cornea [1, 2]. Various modifications of surgical methods and the developing field of tissue engineering offer promising modern approaches to the replacement of conjunctival defects [3–5]. Objective To evaluate the healing process of bulbar conjunctival defects in an in vivo experiment after collagen membrane (CM) transplantation. Material and methods The studies were conducted at the Krasnov Research Institute of Eye Diseases. The experiment involved 16 female Chinchilla rabbits (32 eyes) aged 6 months and weighing 3.5 kg. During the operation, the animals underwent transplantation of Viscoll CM with a collagen concentration of 30 mg/ml and a thickness of 100 μm into the conjunctival defect zone. Biomicroscopy with photo registration, staining of the ocular surface with fluorescein, optical coherence tomography on a SOLIX tomograph (Optovue, USA) in the Corneal line mode on the 1st, 7th, 14th day, 1, 3 and 6 months after transplantation and histological examination after 1, 3 and 6 months from the beginning of the experiment were performed. Results Moderate conjunctival injection in the experimental group took place on the 7th day. OCT showed the presence of conjunctival epithelium in the form of a strip of hyporeflective tissue covering the hyperreflective zone of the transplant. Histological examination showed complete replacement of CM with newly formed tissue covered with multilayered flat nonkeratinizing epithelium of varying thickness with migration of conjunctival cells into the thickness of newly formed tissue, as well as the absence of fibrous tissue. Conclusion Replacement of conjunctival defects with CM promotes the process of cell migration into the structure of the material while maintaining the epitheliomorphic structure and intercellular contacts, which indicates the biocompatibility of the material under study and creates the prerequisites for its further use in clinical practice to eliminate conjunctival defects. Key words: conjunctiva; conjunctival reconstruction; tissue engineering; conjunctival epithelium; collagen