THE MORPHOLOGICAL STUDY OF THE RABBIT EYE SCLERA FOLLOWING THE SCLERA-STRENGTHENING OPERATIONS WITH THE USE OF UV CROSS-LINKED TRANSPLANTS

Aim. The objective of the present study was the comparative evaluation of the morphological characteristics of the reaction of the ocular tissues following experimental scleroplasty with the application of the xenografts from UV-irradiated and non-irradiated pericardium. Materials and methods. To elucidate the morphological characteristics of the reaction of the eye tissues to experimental scleroplasty, we used histological sections of the 16 eyes of 8 rabbits. The animals were allocated to two groups. Those in group 1 underwent sclera-strengthening operations as described by Khatminsky with the use of UV cross-linked xenotransplants from the pericardium. Part of them was preliminarily subjected either to UV-irradiation at a wavelength of 370 nm and an irradiation power of 5 mW/cm2 for 20 minutes or to the treatment with a 0.5% aqueous solution of riboflavin during 30 minutes (the right eyes from 4 animals). The remaining rabbits comprised group 2 and were operated using the same procedure with the application of the xenotransplants from the non-irradiated pericardium. The left eyes of all the animals remained intact and serves as the controls. The enucleated eyes were subjected to the microscopic and histological examination within 2 weeks (two rabbits from each group) and 1 month after surgery. Results. The morphological study of the enucleated eyes obtained within 2 weeks after the surgical intervention gave evidence of only the mild aseptic inflammatory reaction in the form of a lean rim composed from lymphocyte-like cells buried deep in the sclera close to the transplants from the UV-irradiated pericardium. The histological studies carried out within 1 month after the operation have demonstrated the signs of formation of a connective tissue capsule. The sections through the sclera of the enucleated eyes with the use of the biological materials from the non-irradiated pericardium obtained 2 weeks after the operation at the borderline with the transplants exhibited the clearly visualized signs of aseptic inflammation with massive lympho-macrophage infiltration and the presence of a large amount of fibroblasts. Only isolated areas of the granulation tissue were identified within 1 month after the intervention. Conclusion. The histological study of the enucleated rabbit eyes conducted within 2 weeks after experimental scleroplasty has demonstrated the less pronounced reaction of the ocular tissues to the introduction of the UV-irradiated xenografts in comparison with that of the non-irradiated ones. One month after the surgical intervention with the application of the xenotransplants from the UV cross-linked pericardium, the histological signs of the formation of the capsules from the connective tissue were well apparent in the association with the mild inflammatory reaction of the ocular tissues. The animals operated with the use of the non-irradiated biological materials from the pericardium experienced massive inflammatory lympho-macrophage infiltration and exhibited only isolated areas of the developing granulation tissue.