Bone Regeneration in the Application of a New Device for Osteosynthesis in the Experiment

Background. Treatment of residual cavities after radical surgery for bone diseases is a vital problem of modern traumatology. Currently, there is an active search for devices both for osteosynthesis and bone-substituting masses. Aims. The purpose of this work was to test a new device for osteosynthesis. It can be used both for fixing bone fragments, and for studying the morphological features of bone regenerate in experiment.

Materials and methods. A device for bone osteosynthesis of tubular bones in an experiment (Patent of the Russian Federation N 20116121487) was applied. The device consisted of two half-bushings, fastened to each other by a fierce clamp. Polypropylene was used as the material for the half-bushings, therefore no immunological reactions were observed. On the inner surface there were silicone cylinders, which directed pressure on the fragments and did not disturb the nutrition of the periosteum. The experiment was performed on Wistar rats. The surgical defect of the femur was filled with hydroxyapatite. Two groups of animals were identified. The bone in the first group was fixed by the device. The wire cerclage was used in the second group.

Results. The study showed that the developed device does not disturb the nutrition of the periosteum, and also tightly fixes the osteoplastic material in the bone defect. Histological examination showed that bone regeneration was faster when the device was used. On the 21st day of the experiment, the regenerate filled the defect in the control group by 62 %, and in the experimental group by 73 %. The regenerate was represented by a woven bone. In all animals, bone regenerate formed a strong osteo-integrative connection with the maternal bone. In both groups, it looked like a mature bone tissue at the end of the experiment (28 days).

Conclusion. The data indicate that the device does not disturb the processes of bone formation and allows for more efficient use osteoplastic material.

The Possibilities of Magnetic Resonance Imaging in the Diagnosis of Microstructural Changes of the Subchondral Bone in Osteoarthritis

Background. Magnetic resonance imaging not only has powerful capabilities for visualization, but is also of interest in terms of obtaining ideas about microstructural and biochemical changes in the tissues of the joints in osteoarthritis.

Aims. To assess the possibility of T2-images of magnetic resonance imaging in the diagnosis of microstructural changes in the subchondral bone in osteoarthritis.

Materials and methods. 62 patients with osteoarthritis and 8 volunteers without osteoarthritis were examined. All patients underwent magnetic resonance imaging of knee. To assess the variability of transverse relaxation time, the T2-images segmentation of the subchondral segmentation in the frontal projection was performed by hand. The proton density was estimated from a 3D histogram on a scale of 0 to 255.

Results. At the first stage of osteoarthritis, the intensity of the magnetic resonance signal decreases over the entire surface of the tibial plateau, with minimal values in the region of the medial part of the knee joint. At stage 2 osteoarthritis, there was an even greater decrease in the number of protons that made the phase transition with the lowest value in the medial region. The subchondral bone texture in stage 3 was characterized by a significant decrease in signal intensity in the region of the medial plateau of the tibia. In the terminal stage of osteoarthritis.

Conclusion. The revealed regularity of the change in the relaxation time spectrum of T2-images reflects the degenerative process in subchondral bone with osteoarthritis.

Cyclin D1 Gene Silencing Promotes IL-1β-Induced Apoptosis in Rat Chondrocytes

This study investigated the effects of cyclin D1 gene silencing on cell proliferation and apoptosis of interleukin-1β (IL-1β)-induced osteoarthritis (OA) chondrocytes. Chondrocytes from healthy sprague-dawley rats were divided into blank, OA model (chondrocytes underwent IL-1β inducement), OA trial (chondrocytes underwent IL-1β inducement with cyclin D1-shRNA treatment), and negative control (NC; chondrocytes underwent IL-1β inducement and control-shRNA treatment) groups. Cell proliferation was assessed by CCK-8 assay, and cell cycle and apoptosis by flow cytometry. qRT-PCR and Western blotting were performed to detect cyclin D1 and apoptosis-related factors expression levels. Chondrocyte proliferation increased after 72-96 h after incubation. The OA trial group exhibited reduced cell proliferation at 48, 72, and 96 h after treatment. The OA model, OA trial, and NC groups all contained more cells arrested in G1 phase and had higher apoptosis rates than the blank group. Additionally, the OA trial group contained more cells arrested in G1 phase, with increased apoptosis rates compared to the OA model and NC groups. The OA model group had lowest expression of cyclin D1 whereas the blank group contained the highest among the four groups. qRT-PCR also showed that the OA model, OA trial, and NC groups all had increased expression levels of Bax and reduced expression levels of Bcl-2 and P53 compared to the blank group, whereby by the OA group had the most significant change. The combined evidence in our study shows that cyclin D1 gene silencing suppresses proliferation and induces apoptosis of rat chondrocytes in IL-1β-induced OA. J. Cell. Biochem. 119: 290-299, 2018. © 2017 Wiley Periodicals, Inc.