Clinical and morphological correlations of corneal repair in rabbits after modeling of stromal defect and tectonic keratoplasty using human lenticules

PURPOSE: anterior segment optical coherence tomography (OCT) and histological examination. MATERIAL AND METHODS: Thirty laboratory rabbits of the Soviet Chinchilla breed were used. All animals were sexually mature males and were randomly assigned to three groups. In group 1, a mechanical corneal defect created by keratectomy using a trephine and dissector was replaced by suturing two decellularized human lenticules, forming a graft complex of the required thickness. In group 2, the defect was replaced in the same manner, but intact human lenticules were used as graft material. In group 3, the defect was covered with Alloplant material. For noninvasive postoperative assessment of corneal status, anterior segment OCT was performed on days 7, 30, and 60. Some animals were removed from the experiment at each time point: two animals per group on day 7, two per group on day 30, and six per group on day 60. Enucleated eyes were subjected to histological examination with hematoxylin and eosin staining. RESULTS: Tectonic keratoplasty using decellularized lenticules (group 1) demonstrated superior outcomes compared with intact lenticules (group 2) and surface keratoplasty with Alloplant (group 3). Good graft integration with recipient tissues was observed, allowing compensation for the induced stromal defect. The postoperative period was characterized by moderate fibroplasia, the corneal surface remained smooth, no opacities developed, and by day 60 recipient keratocytes were detected within the lenticular tissue. In group 2, pronounced immune aggression against the xenogeneic material resulted in insufficient graft integration, marked inflammatory response, corneal melting with the formation of descemetocele and iridocorneal adhesions, emphasizing the importance of reducing graft immunogenicity. In group 3, persistence of stromal tissue deficiency was observed, and the defect zone had an irregular surface despite compensatory epithelial hyperplasia. CONCLUSION: The study confirms the feasibility of using a complex of decellularized lenticules for tectonic keratoplasty, with potential for application in clinical practice in situations of full-thickness graft shortage. Anterior segment OCT proved informative for clinical corneal assessment, however, a comparative histological analysis revealed specific pathomorphological features of corneal repair after tectonic keratoplasty that may be valuable for future studies in the human population.