Adipose-Derived Extract Suppresses IL-1β-Induced Inflammatory Signaling Pathways in Human Chondrocytes and Ameliorates the Cartilage Destruction of Experimental Osteoarthritis in Rats

We investigated the effects of adipose-derived extract (AE) on cultured chondrocytes and in vivo cartilage destruction. AE was prepared from human adipose tissues using a nonenzymatic approach. Cultured human chondrocytes were stimulated with interleukin-1 beta (IL-1β) with or without different concentrations of AE. The effects of co-treatment with AE on intracellular signaling pathways and their downstream gene and protein expressions were examined using real-time PCR, Western blotting, and immunofluorescence staining. Rat AE prepared from inguinal adipose tissues was intra-articularly delivered to the knee joints of rats with experimental osteoarthritis (OA), and the effect of AE on cartilage destruction was evaluated histologically. In vitro, co-treatment with IL-1β combined with AE reduced activation of the p38 and ERK mitogen-activated protein kinase (MAPK) pathway and nuclear translocation of the p65 subunit of nuclear factor-kappa B (NF-κB), and subsequently downregulated the expressions of matrix metalloproteinase (MMP)-1, MMP-3, MMP-13, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-4, IL-6, and IL-8, whereas it markedly upregulated the expression of IL-1 receptor type 2 (IL-1R2) in chondrocytes. Intra-articular injection of homologous AE significantly ameliorated cartilage destruction six weeks postoperatively in the rat OA model. These results suggested that AE may exert a chondroprotective effect, at least in part, through modulation of the IL-1β-induced inflammatory signaling pathway by upregulation of IL-1R2 expression.

MORPHOLOGICAL CHANGES IN THE TISSUES OF THE RABBIT KNEE JOINT DUE TO EXPERIMENTAL OSTEOARTHRITIS AFTER THE USE OF MESENCHYMAL STEM CELLS

The purpose of the study was to investigate the regenerative processes in the knee joint of rabbits with experimental osteoarthritis after using of allogeneic bone marrow stem cells and a traditional treatment with the non-steroidal anti-inflammatory drug Meloxicam. For the experiment were used 27 male California rabbits (males). Three groups of animals were formed: a control group; the first experimental group treated by the traditional method; the second experimental group treated with allogeneic mesenchymal stem cells (MSC). Animals in the three groups were subjected to osteoarthritis of the knee joint by double injection of 3.44% retinol acetate into the joint cavity at a dose of 1 ml at intervals of 7 days. Tissue from the affected site was sampled for histological examination at 7, 14 and 28 days. The histological sections were stained with haematoxylin-eosin and examined under a microscope. It has been established that intra-articular administration of 3.5 × 106 cells of allogeneic MSCs in experimental osteoarthritis contributes to the restoration of the superficial layer of cartilage, as evidenced by the formation of columns of chondrocytes in the middle layer of articular cartilage and the appearance of isogenic groups of cartilage cells with basophilic cytoplasm in the matrix, uniform articular surface. The use of the traditional method of treating rabbits using the drug Meloxicam is accompanied by incomplete chondrogenesis: part of the chondrocytes is localized in typical chambers, in some cases chondrocyte chambers did not differentiate; articular cartilage had unequal thickness, cell placement was uneven.

Morphofunctional Characteristics of Chondrocyte Proliferation in Experimental Osteoarthritis in Rats

Osteoarthritis is one of the most common degenerative joint diseases. The study of the causes of its occurrence and development is relevant to this day. The lack of data on the causes of its occurrence and development complicates the treatment process. It is known that with the development of this disease, the proliferation of chondrocytes in the articular cartilage progresses at different stages, but the mechanism of this process is poorly understood. An increase in proliferation leads to a sharp increase in the process of autophagy, which in turn affects a decrease in the lubricating function of both cartilage and synovial fluid, which leads to an irreversible stage of joint degeneration. The problem of reducing the viscoelastic properties of cartilage can be solved by introducing natural chondroprotectors, one of which is surfactant proteins. To study the proliferative properties, a research work was carried out, during which osteoarthritis was experimentally simulated in Wistar rats by introducing a solution of medical talc. This led to a decrease in the lubricating function of the synovial fluid and an increase in the number of chondrocytes. However, when using a lubricant based on a substance containing surfactant proteins, the lubricating function of the synovial fluid improved, which contributed to the restoration of cartilage in osteoarthritis.

Glucosamine and Chondroitin Sulfate: Is There Any Scientific Evidence for Their Effectiveness as Disease-Modifying Drugs in Knee Osteoarthritis Preclinical Studies?—A Systematic Review from 2000 to 2021

Glucosamine and chondroitin sulfate have been proposed due to their physiological and functional benefits in the management of osteoarthritis in companion animals. However, the scientific evidence for their use is still controversial. The purpose of this review was to critically elucidate the efficacy of these nutraceutical therapies in delaying the progression of osteoarthritis, evaluating their impact on the synovial knee joint tissues and biochemical markers in preclinical studies by systematically reviewing the last two decades of peer-reviewed publications on experimental osteoarthritis. Three databases (PubMed, Scopus and, Web of Science) were screened for eligible studies. Twenty-two articles were included in the review. Preclinical studies showed a great heterogeneity among the experimental designs and their outcomes. Generally, the evaluated nutraceuticals, alone or in combination, did not seem to prevent the subchondral bone changes, the synovial inflammation or the osteophyte formation. However, further experimental studies may be needed to evaluate their effect at those levels. Regarding the cartilage status and biomarkers, positive responses were identified in approximately half of the evaluated articles. Furthermore, beneficial effects were associated with the pre-emptive administrations, higher doses and, multimodality approaches with some combined therapies. However, additional studies in the long term and with good quality and systematic design are required.

The role of intra-articular neuronal CCR2 receptors in knee joint pain associated with experimental osteoarthritis in mice

Background C–C chemokine receptor 2 (CCR2) signaling plays a key role in pain associated with experimental murine osteoarthritis (OA) after destabilization of the medial meniscus (DMM). Here, we aimed to assess if CCR2 expressed by intra-articular sensory neurons contributes to knee hyperalgesia in the early stages of the model. Methods DMM surgery was performed in the right knee of 10-week-old male wild-type (WT), Ccr2 null, or Ccr2RFP C57BL/6 mice. Knee hyperalgesia was measured using a Pressure Application Measurement device. CCR2 receptor antagonist (CCR2RA) was injected systemically (i.p.) or intra-articularly (i.a.) at different times after DMM to test its ability to reverse knee hyperalgesia. In vivo Ca2+ imaging of the dorsal root ganglion (DRG) was performed to assess sensory neuron responses to CCL2 injected into the knee joint cavity. CCL2 protein in the knee was measured by ELISA. Ccr2RFP mice and immunohistochemical staining for the pan-neuronal marker, protein gene product 9.5 (PGP9.5), or the sensory neuron marker, calcitonin gene-related peptide (CGRP), were used to visualize the location of CCR2 on intra-articular afferents. Results WT, but not Ccr2 null, mice displayed knee hyperalgesia 2–16 weeks after DMM. CCR2RA administered i.p. alleviated established hyperalgesia in WT mice 4 and 8 weeks after surgery. Intra-articular injection of CCL2 excited sensory neurons in the L4-DRG, as determined by in vivo calcium imaging; responses to CCL2 increased in mice 20 weeks after DMM. CCL2, but not vehicle, injected i.a. rapidly caused transient knee hyperalgesia in naïve WT, but not Ccr2 null, mice. Intra-articular CCR2RA injection also alleviated established hyperalgesia in WT mice 4 and 7 weeks after surgery. CCL2 protein was elevated in the knees of both WT and Ccr2 null mice 4 weeks after surgery. Co-expression of CCR2 and PGP9.5 as well as CCR2 and CGRP was observed in the lateral synovium of naïve mice; co-expression was also observed in the medial compartment of knees 8 weeks after DMM. Conclusions The findings suggest that CCL2-CCR2 signaling locally in the joint contributes to knee hyperalgesia in experimental OA, and it is in part mediated through direct stimulation of CCR2 expressed by intra-articular sensory afferents.