Dynamics of pathomorphological changes of ultrastructural organization of intervertebral disc at different terms of experimental opioid influence and with its cancellation

Abstract

Background. Patients with degenerative diseases of the spine - "difficult patients". Often, exhausted by long-term pain, they have a dependence, and sometimes tolerance to various analgesics, which greatly reduces the effectiveness of routinely used in the hospital anesthesia. Objective. The aim of our work was to study the features of pathomorphological manifestations of the structural components of the intervertebral disc at different terms of opioid influence and at the difference at the ultrastructural level in the experiment. Methods. The material of the study were sexually mature, white, nonlinear rats - males in the amount of 90 hundred animals, weighing 92 - 103 g, aged 4.5 months. Animals were injected with Nalbuphine at home, once daily for one day (10-11 am) for 42 days. The initial dose of Nalbuphine was 8 mg / kg during the first week, 15 mg / kg during the second week; 20 mg / kg during the third week; 25 mg / kg during the fourth week; 30 mg / kg during the fifth week and 35 mg / kg during the sixth week of the experimental opioid effect. Thus created the conditions for chronic opioid exposure. Intervertebral discs of rats were used as material for ultrastructural study. Results and conclusion. As a result of our study, we found that at the end of 21 days we found the progression of alternative changes in the cellular elements of the gelatinous nucleus, characterized by the development of necrotic changes in notochondral cells, as well as chondroptosis of chondrocytes. Preserved notochondral cells were rarely visualized. In some places, there were notochondral cells in which the nucleus disintegrated into separate fragments filled with heterochromatin, and the remains of organelle membranes were localized in the enlightened cytoplasm. Pronounced destructive changes were found in chondrocytes. After 28 days, the changes progressed, this was manifested by the fact that in the pulpal nucleus there were extensive cell-free zones filled with a significant amount of granular intensely osmophilic mass. Notochondral cells and most chondrocytes underwent necrotic changes. After 35 days at the ultrastructural level revealed pronounced changes in the structural elements of the gelatinous nucleus and fibrous ring. Extensive cell-free zones were localized in the gelatinous nucleus, with a somewhat compacted matrix in which an intensely osmophilic fine-grained deep mass accumulated. With the abolition of opioid exposure at the end of 56 days, we found pronounced changes in notochondral cells and in the vast majority of chondrocytes. The matrix of the gelatinous nucleus was compacted, it showed thickened collagen fibrils. Most of the cellular elements of the gelatinous nucleus were at different stages of necrosis, and some chondrocytes - chondroptosis. Vacuoles filled with enlightened contents also appeared in the cytoplasm. The nucleus was compacted, condensation of chromatin was observed. In such areas, the fibrils of collagen fibers were loose, stratified, disintegrated and lysed.