Rat Knee Research Articles

Enhancement of acellular cartilage matrix scaffold by Wharton's jelly mesenchymal stem cell-derived exosomes to promote osteochondral regeneration

Articular cartilage defect repair is a problem that has long plagued clinicians. Although mesenchymal stem cells (MSCs) have the potential to regenerate articular cartilage, they also have many limitations. Recent studies have found that MSC-derived exosomes (MSC-Exos) play an important role in tissue regeneration. The purpose of this study was to verify whether MSC-Exos can enhance the reparative effect of the acellular cartilage extracellular matrix (ACECM) scaffold and to explore the underlying mechanism. The results of in vitro experiments show that human umbilical cord Wharton's jelly MSC-Exos (hWJMSC-Exos) can promote the migration and proliferation of bone marrow-derived MSCs (BMSCs) and the proliferation of chondrocytes. We also found that hWJMSC-Exos can promote the polarization of macrophages toward the M2 phenotype. The results of a rabbit knee osteochondral defect repair model confirmed that hWJMSC-Exos can enhance the effect of the ACECM scaffold and promote osteochondral regeneration. We demonstrated that hWJMSC-Exos can regulate the microenvironment of the articular cavity using a rat knee joint osteochondral defect model. This effect was mainly manifested in promoting the polarization of macrophages toward the M2 phenotype and inhibiting the inflammatory response, which may be a promoting factor for osteochondral regeneration. In addition, microRNA (miRNA) sequencing confirmed that hWJMSC-Exos contain many miRNAs that can promote the regeneration of hyaline cartilage. We further clarified the role of hWJMSC-Exos in osteochondral regeneration through target gene prediction and pathway enrichment analysis. In summary, this study confirms that hWJMSC-Exos can enhance the effect of the ACECM scaffold and promote osteochondral regeneration.

A Comparative Immunohistochemical and Quantitative Study of the Epiligament of the Medial Collateral and Anterior Cruciate Ligament in Rat Knee

The aim of the present study was to evaluate the importance of the epiligament for the difference in the healing potential of the knee anterior cruciate and medial collateral ligament. To do so, we compared the structure of the anterior cruciate and the medial collateral ligament and evaluated the differences in the expression of collagen types I, III and V in a rat knee. We have also conducted a comparative quantitative analysis of the number of cells per mm2 in the two ligaments. Tissue samples were obtained from the anterior cruciate and medial collateral ligament of 10 knee joints taken from five 8-month-old Wistar rats. We used standard hematoxylin and eosin staining, in addition to immunohistochemical staining with monoclonal antibodies against collagen types I, III and V. A semi-quantitative analysis of the expression was made through ImageJ, while Student’s T-test was used for the statistical analysis. Our results showed higher expression of all collagen types in the epiligament, compared to the ligament proper and difference in the expression between the medial collateral and the anterior cruciate ligament in favor of the first. We also reported a statistically significant difference in the number of cells per mm2 between the two ligaments and their epiligaments. Our findings show a higher number of cells and a stronger expression of certain collagen types in the epiligament of the medial collateral compared to the anterior cruciate ligament, which may be related to the difference in their healing potential.

Elevated expression of MMP8 and MMP9 contributes to diabetic osteoarthritis progression in a rat model

BackgroundKnowledge regarding the pathogenesis of osteoarthritis (OA) is very limited. Previous studies have shown that matrix metalloproteinase (MMP) 8 and MMP9 were upregulated in patients with diabetic OA. However, their regulatory functions and mechanisms in diabetic OA are not fully understood.MethodsDiabetic OA rats were constructed using a high-fat diet combined with streptozotocin (STZ) induction. Safranin O-Fast green staining was used to detect the pathological changes in rat knee cartilage. MMP8 and MMP9 overexpression vectors or siRNAs were injected into diabetic OA rats to overexpress or knockdown the expression of MMP8 and MMP9, which was verified by real-time quantitative PCR (RT-qPCR). The expression of MMP8 and MMP9, chondrocyte differentiation markers collagen type II alpha 1 (COL2A1) and collagen type I alpha 1(COL1A1), and antiapoptotic protein BCL2 were detected using immunohistochemistry (IHC), and the number of apoptotic cells was detected by the transferase-mediated d-UTP nick-end-labeling (TUNEL) assay.ResultsHigh-fat diet combined with STZ-induced rats exhibited joint cartilage damage, morphological changes, and increased expression of MMP8 and MMP9. Overexpression of MMP8 and MMP9 in the joint cavity further aggravated the pathological morphological changes, decreased the expression of COL2A1 and COL1A1, increased the expression of BCL2, and promoted cell apoptosis in diabetic OA rats. The use of siRNA to inhibit MMP8 and MMP9 levels in the cartilage joints significantly reversed the decrease in COL2A1 and COL1A1 expression and partially reversed BCL2 expression and chondrocyte apoptosis.ConclusionMMP8 and MMP9 promoted rat diabetic OA model. The underlying mechanism may be related to inhibiting cartilage differentiation and promoting chondrocyte apoptosis.

Effect of intra-articular dexmedetomidine on experimental osteoarthritis in rats.

Pharmacological treatment of osteoarthritis is still inadequate due to the low efficacy of the drugs used. Dexmedetomidine via the intra-articular (i.a.) route might be an option for the treatment of osteoarthritis-associated pain. The present study assessed the analgesic and anti-inflammatory effects of dexmedetomidine administered via the i.a. route in different doses in an experimental model of rat knee osteoarthritis induced with monosodium iodoacetate. Rats were allocated to four groups with 24 animals in each group. The OA (osteoarthritis), DEX-1 (dexmedetomidine in dose of 1μg/kg) and DEX-3 (dexmedetomidine in dose of 3μg/kg) groups were subjected to induction of osteoarthritis through injection of monosodium iodoacetate (MIA) via the i.a. route on the right knee; the control group was not subjected to osteoarthritis induction. Clinical assessment was performed on day 0 (before osteoarthritis induction) and then on days 5, 10, 14, 21 and 28 after induction. Treatment was performed on day 7 via the i.a. route, consisting of dexmedetomidine in doses of 1 and 3 μg/kg, while group OA received 0.9% normal saline. The animals were euthanized on days 7, 14, 21 and 28. Samples of the synovial membrane were collected for histopathological analysis, and the popliteal lymph nodes were collected for measurement of cytokines (interleukin [IL] IL-6, tumor necrosis factor alpha [TNF-α]). Dexmedetomidine (1 and 3 μg/kg) significantly reduced the animals' weight distribution deficit during the chronic-degenerative stage of osteoarthritis and improved the pain threshold throughout the entire experiment. Histological analysis showed that dexmedetomidine did not cause any additional damage to the synovial membrane. The TNF-α levels decreased significantly in the DEX-3 group on day 28 compared with the OA group. Dexmedetomidine reduced pain, as evidenced by clinical parameters of osteoarthritis in rats, but did not have an anti-inflammatory effect on histological evaluation.

Low-Intensity Pulsed Ultrasound Suppresses Synovial Macrophage Infiltration and Inflammation in Injured Knees in Rats

This study was designed to investigate how low-intensity pulsed ultrasound (LIPUS) suppresses traumatic joint inflammation and thereafter affects the progression of posttraumatic osteoarthritis. Intra-articular fracture (IAF) was created in the right knee of rats. LIPUS was applied to the knees with IAFs for 20 min/d for 2 wk—LIPUS(+) group. The study controls included rats that underwent sham surgery but no LIPUS treatment (control group) or underwent IAF surgery without LIPUS treatment—LIPUS(–) group. By histology, at 4 wk, leukocyte infiltration in the synovium was reduced in the LIPUS(+) group. Furthermore, LIPUS treatment reduced CD68+ macrophages in the synovium and limited their distribution mostly in the subintimal synovium. Measured with enzyme-linked immunosorbent assay, interleukin-1β (IL-1β) in the joint fluid of the LIPUS(+) group was reduced to about one-third that in the LIPUS(–) group. By reducing synovial macrophages and lowering IL-1β in the joint fluid, LIPUS is potentially therapeutic for posttraumatic osteoarthritis.

Angiotensin II triggers knee joint lesions in experimental osteoarthritis.

This study aimed to evaluate the involvement of Angiotensin II (Ang II) in joint lesions associated with osteoarthritis (OA) in vitro and in vivo. Chondrocyte cultures were obtained from knee joints of neonatal rats and stimulated with Ang II/MIA/ACE inhibitors. In vivo, rats treated or not with the ACE inhibitor captopril, received daily injections of Ang II or sodium monoiodoacetate (MIA) in knee joints for evaluation of cartilage, bone, and synovial lesions. Cultured chondrocytes expressed the mRNA for Ace, Agtr1, Agtr2, and Mas1. Stimulating cells with Ang II reduced chondrocyte viability and metabolism. Accordingly, in vivo Ang II injection into the knees of rats triggered hyperalgesia, joint edema, increased the number of leukocytes in the joint cavity, and induced cartilage lesions associated with OA alterations. In further experiments, Ang II synthesis was prevented with the ACE inhibitor Captopril in the context of MIA-induced OA. Ang II inhibition with captopril improved the OARSI score, induced chondroprotection, and reduced the leukocyte recruitment from synovium after MIA. Additionally, captopril prevented MIA-induced bone resorption, by decreasing the number of osteoclasts and increasing the expression of IL-10 in the bone. In vitro, inhibiting Ang II synthesis decreased MIA-induced chondrocyte death and increased Col2a1 transcription. Ang II induces chondrocyte death and joint tissue damages associated with OA and its modulation can be a therapeutic strategy in osteoarthritis.

Determination of the decalcification time of rat sternum, knee joint and nasal cavity specimens

Determination of the decalcification time of rat sternum, knee joint and nasal cavity specimens

Low-Intensity Pulsed Ultrasound Promotes Autophagy-Mediated Migration of Mesenchymal Stem Cells and Cartilage Repair

Mesenchymal stem cell (MSC) migration is promoted by low-intensity pulsed ultrasound (LIPUS), but its mechanism is unclear. Since autophagy is known to regulate cell migration, our study aimed to investigate if LIPUS promotes the migration of MSCs via autophagy regulation. We also aimed to investigate the effects of intra-articular injection of MSCs following LIPUS stimulation on osteoarthritis (OA) cartilage. For the in vitro study, rat bone marrow-derived MSCs were treated with an autophagy inhibitor or agonist, and then they were stimulated by LIPUS. Migration of MSCs was detected by transwell migration assays, and stromal cell-derived factor-1 (SDF-1) and C-X-C chemokine receptor type 4 (CXCR4) protein levels were quantified. For the in vivo study, a rat knee OA model was generated and treated with LIPUS after an intra-articular injection of MSCs with autophagy inhibitor added. The cartilage repair was assessed by histopathological analysis and extracellular matrix protein expression. The in vitro results suggest that LIPUS increased the expression of SDF-1 and CXCR4, and it promoted MSC migration. These effects were inhibited and enhanced by autophagy inhibitor and agonist, respectively. The in vivo results demonstrate that LIPUS significantly enhanced the cartilage repair effects of MSCs on OA, but these effects were blocked by autophagy inhibitor. Our results suggest that the migration of MSCs was enhanced by LIPUS through the activation autophagy, and LIPUS improved the protective effect of MSCs on OA cartilage via autophagy regulation.

Application and research of adjuvant therapy in sports injury rehabilitation based on nano-biomaterials

The use of biomedical materials to prepare tissue engineering scaffold technology to construct functional auxiliary materials is of great significance in the prevention and treatment of sports injury complications. In this study, the most common sports injury, that is, the knee meniscus injury, is the main body of the study. Chitosan (CS) and nano silk fibroin (SFP) were used to prepare CS-SFP multi-microchannel catheter scaffold (CS-SFP MMC) to enhance its mechanical properties. The characterisation, porosity, mechanical properties and biocompatibility of the scaffold material were evaluated. The results showed that the scaffold has good biocompatibility, has a suitable pore size and porosity, and provides a sufficient environment for the adhesion and growth of bone cells. At the same time, histological research was performed by constructing a rat knee meniscus injury model. Experiments showed that the healing results of CS-SFP MMC stent in treating knee joint meniscus injury in rats are better than those in control group. This indicated that the CS-SFP MMC stent has an auxiliary effect on meniscus damage repair. Therefore, CS-SFP MMC stent is an ideal bone tissue engineering scaffold material, which has the prospect of providing a new therapeutic material for clinical treatment of bone defects.

Evaluating the value of synchrotron radiation phase-contrast CT imaging in the study of knee joint microstructure

The knee joint is one of the tissues that often appear diseased, and the pathogenesis owing to its structure. Therefore, the micro-structure of the knee joint was studied by synchrotron radiation phasecontrast CT imaging (SRPCI-CT). The contrast and the sharpness of the reconstructed slice were calculated and analysed. From these results, the layer structure of the joint tissue can be seen. The cartilage layer (including the meniscus) is about 1.44 mm, and the epiphyseal layer is about 2.25 mm, which conforms to the actual situation of rat knees. From the 3D images, the structure of the meniscus and the epiphyseal bone can be observed. The epiphyseal bone line is also particularly obvious. Simultaneously, the epiphyseal bone also has a mesh structure, which has the characteristics of both cartilage and tibia. Further research on the tibia can determine that the trabecular bone line is about 130 microns. Finally, the bone volume fraction (BVF) of the joint, the data also reflect the existence of a layer structure, and its scale distribution is consistent with the results of sharpness and contrast analysis. The SRPCI-CT can play an important role in the study micro-structure of joints.

Application of degradable new nano-biomaterials in bone defect repair and its impact on sports health

In addition to good biocompatibility, degradable new biomaterials should also have suitable hydrophilic and hydrophobic properties and mechanical strength, and have a degradation rate that matches the tissue growth rate. From the perspective of bionics, a new biodegradable biomaterial was synthesised to fill bone defects in rats, and compared with the autogenous bone transplantation group, blank control group, and polymeric biomaterials to compare the repair effect of bone defects in rats. This study aimed to explore the effect of new biodegradable materials on the repair of bone defects in rats, evaluate the biocompatibility, degradability, bone conduction capacity, osteoinductive capacity and other properties of the material, provide theoretical basis and reference materials for further research and development of the material, and provide new options and ideas for the development of bone defect repair materials. Sixty rat knee joints were used to establish a full-thickness articular cartilage defect model and were randomly divided into three groups. Group A underwent CPM for 8 h each day; group B underwent CPM for 2 h each day. Both groups underwent CPM for 4 weeks, and then caged. Group C were free to move only in the cage. The repair effect of full-thickness articular cartilage defect in group A was better than that in group B and group C. Interventions given to bone defect repair can significantly promote tissue repair, and at the same time promote the recovery of type II collagen and proteoglycans.

Suppression of TGF-beta activity with remobilization attenuates immobilization-induced joint contracture in rats.

Joint contracture is a common complication of joint injury. This study aimed to assess the effect of inhibiting the transforming growth factor-β (TGF-β) signaling during joint immobilization and remobilization on immobilization-induced joint contracture in rats. The knees of rats were immobilized using Kirschner wires following trauma to the femoral condyles to generate joint contracture. After immobilization, levels of TGF-β and passive extension range of motion (ROM) were measured at different time points, joints were histologically analyzed by hematoxylin and eosin (H&E) and Masson trichrome staining, and the expression of inflammatory or fibrosis-related mediators, including interleukin-1β (IL-1β), phosphorylated Smad2/3 (p-Smad2/3), α-smooth muscle actin (α-SMA) and collagen types I (Col 1) and III (Col 3), were examined in joint capsules using immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR). Rats were also treated with LY2157299, a TGF-β receptor I kinase inhibitor, at different stages of immobilization and remobilization. TGF-β1 levels in the serum and the number of p-Smad2/3+ cells in the joint capsule were significantly elevated after immobilization. ROM decreased during the 6 weeks of immobilization and partly recovered after remobilization. After treatment with LY2157299 during immobilization, the restricted ROM moderately increased, but this effect was stronger when combined with active motion. Mechanistically, the expression of IL-1β, TGF-β, fibrosis-related factors, and the density of collagen significantly decreased after treatment with LY2157299. Inhibiting TGF-β signaling paired with active motion effectively attenuated the formation of immobilization-induced joint contracture in rats.

Inhibition of fibrotic changes in infrapatellar fat pad alleviates persistent pain and articular cartilage degeneration in monoiodoacetic acid-induced rat arthritis model

We have reported that fibrotic changes in infrapatellar fat pad (IFP) after acute joint inflammation are closely associated with persistent pain in rats. In this study, to examine the effects of anti-fibrotic treatment on persistent pain, we used C-type natriuretic peptides (CNP) at the recovery phase after acute joint inflammation. Thirty-two male Wistar rats were used in this study. Monoiodoacetic acid (MIA) was injected intra-articularly to induce IFP fibrosis and persistent pain. CNP was injected after acute inflammatory phase in the same knee joint. Time-course pain-avoidance behavior tests and histological analyses were performed to examine the effects of CNP. Histological evaluations indicated that intra-articular injection of CNP inhibited fibrotic changes in IFP after acute inflammation. Incapacitance tests indicated that MIA injection into rat knee joint quickly decreased the percent weight on ipsilateral limb. In the vehicle group, the decrease was maintained up to day 28, suggesting that pain persistence occurred after acute inflammation (Day 0/Day 28, Est Dif-8.15, CI -10.78∼-5.53, Linear mixed-effect model). In contrast, the pain was alleviated in the CNP group after day 14 (Day0/Day 14, -0.51,-2.62-1.59). In addition, we observed significant improvement in the degree of articular cartilage degeneration at day 14 in the CNP group (OARSI score: vehicle 16.14±4.37 vs CNP 6.87±3.44, P<0.01; Wilcoxon rank sum test). Fibrotic changes in IFP may play important roles in both persistent pain and articular cartilage degeneration.

Effects of Cryotherapy Applied at Different Temperatures on Inflammatory Pain During the Acute Phase of Arthritis in Rats.

The biological mechanisms of cryotherapy for managing acute pain remain unclear. Additionally, it is unknown whether the effectiveness of cryotherapy depends on the applied temperature. This study aimed to clarify the biological effects of cryotherapy and to examine the therapeutic effects of cryotherapy applied at different temperatures in rats. This was an experimental study using a rat knee joint arthritis model. Thirty-five Wistar rats were randomly divided into arthritis (AR), arthritis with 5°C cryotherapy (CR-5), arthritis with 10°C cryotherapy (CR-10), and sham-arthritis control (CON) groups. Arthritis was induced by injecting a mixture of kaolin/carrageenan into the right knee joint. Cryotherapy was applied for 7days starting the day after injection by immersing the right knee joint in 5°C or 10°C water. Joint transverse diameter, pressure pain threshold, and pain-related behaviors were assessed for 7days. The number of CD68-positive cells in the knee joint and the expression of calcitonin gene-related peptide in the spinal dorsal horn 8days after injection were analyzed by immunohistochemical staining. Improvements in transverse diameter, pressure pain threshold, and pain-related behaviors were observed in the CR-5 and CR-10 groups on the 3rd day compared with the AR group. The number of CD68-positive cells and the expression of calcitonin gene-related peptide in the CR-5 and CR-10 groups were significantly decreased compared with the AR group. There were no significant differences in all results between the CR-5 and CR-10 groups. Cryotherapy can ameliorate inflammatory pain through reduction of synovium and central sensitization. Additionally, the effects of cryotherapy lower than 10°C are observed independent of applied temperature. Cryotherapy may be beneficial as a physical therapy modality for pain and swelling management in the acute phase of inflammation. Translational human study is needed to determine the effective cryotherapy temperature for the inflammatory pain.

Transcutaneous application of carbon dioxide improves contractures after immobilization of rat knee joint.

Joint contractures are a major complication following joint immobilization. However, no fully effective treatment has yet been found. Recently, carbon dioxide (CO2) therapy was developed and verified this therapeutic application in various disorders. We aimed to verify the efficacy of transcutaneous CO2 therapy for immobilization-induced joint contracture. Twenty-two Wistar rats were randomly assigned to three groups: caged control, those untreated after joint immobilization, and those treated after joint immobilization. The rats were treated with CO2 for 20 min once a daily either during immobilization, (prevention) or during remobilization after immobilization (treatment). Knee extension motion was measured with a goniometer, and the muscular and articular factors responsible for contractures were calculated. We evaluated muscle fibrosis, fibrosis-related genes (collagen Type 1α1 and TGF-β1) in muscles, synovial intima's length, and fibrosis-related proteins (Type I collagen and TGF-β1) in the joint capsules. CO2 therapy for prevention and treatment improved the knee extension motion. Muscular and articular factors decreased in rats of the treatment group. The muscular fibrosis of treated rats decreased in the treatment group. Although CO2 therapy did not repress the increased expression of collagen Type 1α1, the therapy decreased the expression of TGF-β1 in the treatment group. CO2 therapy for treatment improved the shortening of the synovial membrane after immobilization and decreased the immunolabeling of TGF-β1 in the joint capsules. CO2 therapy may prevent and treat contractures after joint immobilization, and appears to be more effective as a treatment strategy for the deterioration of contractures during remobilization.

Naproxen treatment inhibits articular cartilage loss in a rat model of osteoarthritis.

The effects of naproxen, a nonsteroidal anti-inflammatory drug (NSAID), on articular cartilage degeneration in female Sprague-Dawley rats was examined. Osteoarthritis (OA) was induced by destabilization of the medial meniscus (DMM) in each knee. Rats were treated with acetaminophen (60 mg/kg), naproxen (8 mg/kg), or 1% carboxymethylcellulose (placebo) by oral gavage twice daily for 3 weeks, beginning 2 weeks after surgery. OA severity was assessed by histological Osteoarthritis Research Society International (OARSI) scoring and by measuring proximal tibia cartilage depth using contrast enhanced µCT (n = 6 per group) in specimens collected at 2, 5, and 7 weeks after surgery as well as on pristine knees. Medial cartilage OARSI scores from the DMM knees of naproxen-treated rats were statistically lower (i.e., better) than the medial cartilage OARSI scores from the DMM knees of placebo-treated rats at 5-weeks (8.7 ± 3.6 vs. 13.2 ± 2.4, p = 0.025) and 7-weeks (9.5 ± 1.2 vs. 12.5 ± 2.5, p = 0.024) after surgery. At 5 weeks after DMM surgery, medial articular cartilage depth in the proximal tibia specimens was significantly greater in the naproxen (1.78 ± 0.26 mm, p = 0.005) and acetaminophen (1.94 ± 0.12 mm, p < 0.001) treated rats as compared with placebo-treated rats (1.34 ± 0.24 mm). However, at 7 weeks (2 weeks after drug withdrawal), medial articular cartilage depth for acetaminophen-treated rats (1.36 ± 0.29 mm) was significantly reduced compared with specimens from the naproxen-treated rats (1.88 ± 0.14 mm; p = 0.004). The results indicate that naproxen treatment reduced articular cartilage degradation in the rat DMM model during and after naproxen treatment.

Shockwave Therapy Modulates the Expression of BMP2 for Prevention of Bone and Cartilage Loss in the Lower Limbs of Postmenopausal Osteoporosis Rat Model

Osteoporosis (OP) causes bone loss and weakness, increasing the risk of bone fracture. In this study, rats were divided into Sham, OP, SW(F) (0.25 mJ/mm2 with 1600 impulses to the left medial femur), and SW(T) (0.25 mJ/mm2 with 1600 impulses to the left medial tibia). The bone strength results following SW(T) were better than SW(F) in the modulus, extension at peak load, handleability, and strain at break. SW(T) had the best prevention for bone loss in both lower limbs of ovariectomized (OVX) rats. The cartilage cellular matrixes of both knees were improved in SW(T) and SW(F) compared to that of OP. Serum bone morphogenetic protein 2 (BMP2) in rats undergoing SW(T) or SW(F) was significantly improved compared to that in Sham and OP. The expressions of BMP2, BMP4, and SMAD family member 4 (Smad4) in addition to the Wnt family member 3A (Wnt3a) and Cyclin D1 signaling key factors were significantly induced in the cartilage of both knees by shockwave (SW). SW(T) presented the best efficacy to induce serum BMP2 to prevent bone loss from both lower limbs. Here, we display the protective effects of SW therapy to induce BMP2, BMP4, Smad4, Wnt3a, and Cyclin D1 signaling factors for cartilage loss in both knees of OVX rats.

RETRACTED: Inhibited microRNA-218-5p attenuates synovial inflammation and cartilage injury in rats with knee osteoarthritis by promoting sclerostin

In recent decades, the role of microRNAs (miRNAs) in human diseases has been widely studied. This research is designed to explore the effect of miR-218-5p on knee osteoarthritis (KOA) progression in a rat model with the involvement of sclerostin (SOST). The KOA rat models were constructed by Hulth method, and then were classified into the KOA, miR-218-5p inhibitor, inhibitor negative control (NC), overexpressed (OE)-SOST, OE-NC, miR-218-5p inhibitor + si-SOST, or miR-218-5p inhibitor + si-NC group. The pathological changes of rats' synovial tissues were observed; the apoptosis in rat synovial tissues was assessed; levels of IL-1β, TNF-α, PGE2 and COX-2 in serum and synovial tissues, along with SOD and MDA contents in synovial tissues were determined. The morphological changes in cartilage tissues were observed. MMP-13 and Col II expression in cartilage tissues was assessed; expression of β-catenin and Col2A1 in cartilage tissues was assessed. miR-218-5p and SOST expression in rat knee joint tissues was assessed. KOA rats had increased miR-218-5p expression and decreased SOST expression. MiR-218-5p targeted SOST. Rats injected with miR-218-5p inhibitor and OE-SOST had alleviated pathological changes, reduced TUNEL positive cell rate, decreased serum contents of IL-1β, TNF-α, PGE2, COX-2 and MDA, and increased SOD activity in synovial tissues, alleviated pathological changes, enhanced Col II positive rate and reduced MMP-13 positive rate, decreased β-catenin expression and increased Col2A1 expression in cartilage tissues. The miR-218-5p inhibition could attenuate synovial inflammation and cartilage injury in KOA rats by promoting SOST, which may be helpful for KOA treatment.

Analysis on the expression and value of CCL2 and CCL3 in patients with osteoarthritis

In this study, we investigated the clinical value of CC chemokine ligand 2 (CCL2) and CC chemokine ligand 3 (CCL3) in osteoarthritis (OA). A prospective analysis was performed on 126 patients with rheumatoid arthritis of the knee (observation group (OG)) who admitted to Qilu hospital from August 2016 to August 2018 and 135 healthy controls (control group (CG)) who underwent physical examinations during the same period. The concentrations of CCL2 and CCL3 in peripheral blood were compared between the two groups, and the predictive value of the two on the occurrence, efficacy and prognosis of recurrence of OA were analyzed. In addition, an OA rat model was established to detect the relative protein levels of CCL2 and CCL3 in rat knee joint tissues. There were no statistically significant differences between the two groups in baseline data such as age, body mass index (BMI), gender, smoking, drinking, educational level, family medical history and living environment (P > 0.05). CCL2 and CCL3 increased in peripheral blood of patients in the OG (P < 0.05), both of which were positively correlated with rheumatoid factor (RF) (P < 0.001). CCL2 and CCL3 were of good predictive value for the occurrence, efficacy and prognosis of recurrence of OA (P < 0.001). The relative protein levels of CCL2 and CCL3 in bone and joint tissues of OA rats were significantly higher than those of normal rats (P < 0.001). CCL2 and CCL3 are elevated in peripheral blood of OA patients, which have good predictive value for the occurrence, efficacy and prognosis of recurrence of OA, indicating their potential roles as excellent markers for diagnosis and treatment of OA in the future.

Nanostructured lipid carrier-based smart gel: a delivery platform for intra-articular therapeutics

The promising potential of nano-structured lipid carrier (NLC) polymeric gel of CUR as an effective treatment for rheumatoid arthritis by intra-articular route of administration was investigated. NLC composed of cetylpalmitate, Labrafac PG & Captex 200, Tween 80 and Labrasol. The hot homogenization method employed by melt ultrasonication was used. The formulated NLC dispersions were characterized and were suitably dispersed into the matrix of pluronic F-127(PLF-127) and pluronic F-68 (PLF-68). A two-factor three-level full factorial design was employed to deduce the optimal concentrations of PLF-127 and PLF-68. The optimized formulations were sterilized by gamma radiation. The formulated NLC smart gels were characterized and evaluated for various parameters. The efficacy evaluation by antigen-induced monoarthritis model and biocompatibility testing by histopathological studies was performed. Formulated NLCs exhibited an average particle size of 165.12 nm, entrapment efficiency of 72.15%, and zeta potential of −21.67 mV. The optimized CUR-NLC smart gel was demonstrated to have a sol–gel transformation at 33.21 °C and 94.32% drug release at 84 h. NLC’s which were sterile and easily syringeable, continued to remain within the colloidal range. CUR-NLC smart gels were found to be biocompatible and showed a significant reduction in rat knee joint inflammation compared to free drug.