Effects of Clematis chinensis Osbeck mediated by low-intensity pulsed ultrasound on transforming growth factor-β/Smad signaling in rabbit articular chondrocytes

LIPUS regulates the progression of knee osteoarthritis in mice through primary cilia-mediated TRPV4 channels

Osteoarthritis (OA) is a common disease in middle-aged and elderly people. An imbalance in calcium ion homeostasis will contribute to chondrocyte apoptosis and ultimately lead to the progression of OA. Transient receptor potential channel 4 (TRPV4) is involved in the regulation of intracellular calcium homeostasis. TRPV4 is expressed in primary cilia, which can sense mechanical stimuli from outside the cell, and its abnormal expression is closely related to the development of OA. Low-intensity pulsed ultrasound (LIPUS) can alleviate chondrocyte apoptosis while the exact mechanism is unclear. In this project, with the aim of revealing the mechanism of action of LIPUS, we proposed to use OA chondrocytes and animal models, LIPUS intervention, inhibition of primary cilia, use TRPV4 inhibitors or TRPV4 agonist, and use Immunofluorescence (IF), Immunohistochemistry (IHC), Western Blot (WB), Quantitative Real-time PCR (QP) to detect the expression of cartilage synthetic matrix and endoplasmic reticulum stress markers. The results revealed that LIPUS altered primary cilia expression, promoted synthetic matrix metabolism in articular chondrocytes and was associated with primary cilia. In addition, LIPUS exerted a active effect on OA by activating TRPV4, inducing calcium inward flow, and facilitating the entry of NF-κB into the nucleus to regulate synthetic matrix gene transcription. Inhibition of TRPV4 altered primary cilia expression in response to LIPUS stimulation, and knockdown of primary cilia similarly inhibited TRPV4 function. These results suggest that LIPUS mediates TRPV4 channels through primary cilia to regulate the process of knee osteoarthritis in mice.

Effectiveness of low-intensity pulsed ultrasound on osteoarthritis: molecular mechanism and tissue engineering

Osteoarthritis (OA) is distinguished by pathological alterations in the synovial membrane, articular cartilage, and subchondral bone, resulting in physical symptoms such as pain, deformity, and impaired mobility. Numerous research studies have validated the effectiveness of low-intensity pulsed ultrasound (LIPUS) in OA treatment. The periodic mechanical waves generated by LIPUS can mitigate cellular ischemia and hypoxia, induce vibration and collision, produce notable thermal and non-thermal effects, alter cellular metabolism, expedite tissue repair, improve nutrient delivery, and accelerate the healing process of damaged tissues. The efficacy and specific mechanism of LIPUS is currently under investigation. This review provides an overview of LIPUS's potential role in the treatment of OA, considering various perspectives such as the synovial membrane, cartilage, subchondral bone, and tissue engineering. It aims to facilitate interdisciplinary scientific research and further exploration of LIPUS as a complementary technique to existing methods or surgery. Ongoing research is focused on determining the optimal dosage, frequency, timing, and treatment strategy of LIPUS for OA. Additional research is required to clarify the precise mechanism of action and potential impacts on cellular, animal, and human systems prior to its integration into therapeutic applications.

Mechanisms of vascular invasion after cartilage injury and potential engineering cartilage treatment strategies

Articular cartilage injury is one of the most common diseases in orthopedic clinics. Following an articular cartilage injury, an inability to resist vascular invasion can result in cartilage calcification by newly formed blood vessels. This process ultimately leads to the loss of joint function, significantly impacting the patient's quality of life. As a result, developing anti-angiogenic methods to repair damaged cartilage has become a popular research topic. Despite this, tissue engineering, as an anti-angiogenic strategy in cartilage injury repair, has not yet been adequately investigated. This exhaustive literature review mainly focused on the process and mechanism of vascular invasion in articular cartilage injury repair and summarized the major regulatory factors and signaling pathways affecting angiogenesis in the process of cartilage injury. We aimed to discuss several potential methods for engineering cartilage repair with anti-angiogenic strategies. Three anti-angiogenic tissue engineering methods were identified, including administering angiogenesis inhibitors, applying scaffolds to manage angiogenesis, and utilizing in vitro bioreactors to enhance the therapeutic properties of cultured chondrocytes. The advantages and disadvantages of each strategy were also analyzed. By exploring these anti-angiogenic tissue engineering methods, we hope to provide guidance for researchers in related fields for future research and development in cartilage repair.

LIPUS as a potential strategy for periodontitis treatment: A review of the mechanisms

Periodontitis is a chronic inflammatory condition triggered by oral bacteria. A sustained inflammatory state in periodontitis could eventually destroy the alveolar bone. The key objective of periodontal therapy is to terminate the inflammatory process and reconstruct the periodontal tissues. The traditional Guided tissue regeneration (GTR) procedure has unstable results due to multiple factors such as the inflammatory environment, the immune response caused by the implant, and the operator's technique. Low-intensity pulsed ultrasound (LIPUS), as acoustic energy, transmits the mechanical signals to the target tissue to provide non-invasive physical stimulation. LIPUS has positive effects in promoting bone regeneration, soft-tissue regeneration, inflammation inhibition, and neuromodulation. LIPUS can maintain and regenerate alveolar bone during an inflammatory state by suppressing the expression of inflammatory factors. LIPUS also affects the cellular behavior of periodontal ligament cells (PDLCs), thereby protecting the regenerative potential of bone tissue in an inflammatory state. However, the underlying mechanisms of the LIPUS therapy are still yet to be summarized. The goal of this review is to outline the potential cellular and molecular mechanisms of periodontitis-related LIPUS therapy, as well as to explain how LIPUS manages to transmit mechanical stimulation into the signaling pathway to achieve inflammatory control and periodontal bone regeneration.

[Effect of silk fibroin microcarrier loaded with clematis total saponins and chondrocytes on promoting rabbit knee articular cartilage defects repair]

Objective

To prepare the silk fibroin microcarrier loaded with clematis total saponins (CTS) (CTS-silk fibroin microcarrier), and to investigate the effect of microcarrier combined with chondrocytes on promoting rabbit knee articular cartilage defects repair.

Methods

CTS-silk fibroin microcarrier was prepared by high voltage electrostatic combined with freeze drying method using the mixture of 5% silk fibroin solution, 10 mg/mL CTS solution, and glycerin. The samples were characterized by scanning electron microscope and the cumulative release amount of CTS was detected. Meanwhile, unloaded silk fibroin microcarrier was also prepared. Chondrocytes were isolated from knee cartilage of 4-week-old New Zealand rabbits and cultured. The 3rd generation of chondrocytes were co-cultured with the two microcarriers respectively for 7 days in microgravity environment. During this period, the adhesion of chondrocytes to microcarriers was observed by inverted phase contrast microscope and scanning electron microscope, and the proliferation activity of cells was detected by cell counting kit 8 (CCK-8), and compared with normal cells. Thirty 3-month-old New Zealand rabbits were selected to make bilateral knee cartilage defects models and randomly divided into 3 groups ( n=20). Knee cartilage defects in group A were not treated, and in groups B and C were filled with the unloaded silk fibroin microcarrier-chondrocyte complexes and CTS-silk fibroin microcarrier-chondrocyte complexes, respectively. At 12 weeks after operation, the levels of matrix metalloproteinase 9 (MMP-9), MMP-13, and tissue inhibitor of MMP 1 (TIMP-1) in articular fluid were detected by ELISA. The cartilage defects were collected for gross observation and histological observation (HE staining and toluidine blue staining). Western blot was used to detect the expressions of collagen type Ⅱ and proteoglycan. The inflammatory of joint synovium was observed by histological staining and inducible nitric oxide synthase (iNOS) immunohistochemical staining.

Results

The CTS-silk fibroin microcarrier was spherical, with a diameter between 300 and 500 μm, a porous surface, and a porosity of 35.63%±3.51%. CTS could be released slowly in microcarrier for a long time. Under microgravity, the chondrocytes attached to the surface of the two microcarriers increased gradually with the extension of culture time, and the proliferation activity of chondrocytes at 24 hours after co-culture was significantly higher than that of normal chondrocytes ( P<0.05). There was no significant difference in proliferation activity of chondrocytes between the two microcarriers ( P>0.05). In vivo experiment in animals showed that the levels of MMP-9 and MMP-13 in group C were significantly lower than those in groups A and B ( P<0.05), and the level of TIMP-1 in group C was significantly higher ( P<0.05). Compared with group A, the cartilage defects in groups B and C were filled with repaired tissue, and the repaired surface of group C was more complete and better combined with the surrounding cartilage. Histological observation and Western blot analysis showed that the International Cartilage Repair Scoring (ICRS) and the relative expression levels of collagen type Ⅱ and proteoglycan in groups B and C were significantly better than those in group A, and group C was significantly better than group B ( P<0.05). The histological observation showed that the infiltration of synovial inflammatory cells and hyperplasia of small vessels significantly reduced in group C compared with groups A and B. iNOS immunohistochemical staining showed that the expression of iNOS in group C was significantly lower than that in groups A and B ( P<0.05).

Conclusion

CTS-silk fibroin microcarrier has good CTS sustained release effect and biocompatibility, and can promote the repair of rabbit cartilage defect by carrying chondrocyte proliferation in microgravity environment.

Cartilage Repair Using Clematis Triterpenoid Saponin Delivery Microcarrier, Cultured in a Microgravity Bioreactor Prior to Application in Rabbit Model

Cartilage tissue engineering provides a promising method for the repair of articular cartilage defects, requiring appropriate biological scaffolds and necessary growth factors to enhance the efficiency of cartilage regeneration. Here, a silk fibroin (SF) microcarrier and a clematis triterpenoid saponin delivery SF (CTS-SF) microcarrier were prepared by the high-voltage electrostatic differentiation and lyophilization method, and chondrocytes were carried under the simulated microgravity condition by a rotating cell culture system. SF and CTS-SF microspheres were relatively uniform in size and had a porous structure with good swelling and cytocompatibility. Further, CTS-SF microcarriers could sustainably release CTSs in the monitored 10 days. Compared with the monolayer culture, chondrocytes under the microgravity condition maintained a better chondrogenic phenotype and showed better proliferation ability after culture on microcarriers. Moreover, the sustained release of CTS from CTS-SF microcarriers upregulated transforming growth factor-β, Smad2, and Smad3 signals, contributing to promote chondrogenesis. Hence, the biophysical effects of microgravity and bioactivities of CTS-ST were used for chondrocyte expansion and phenotype maintenance in vitro. With prolonged expansion, SF- and CTS-SF-based microcarrier-cell composites were directly implanted in vivo to repair rabbit articular defects. Gross evaluations, histopathological examinations, and biochemical analysis indicated that SF- and CTS-SF-based composites exhibited cartilage-like tissue repair compared with the nontreated group. Further, CTS-SF-based composites displayed superior hyaline cartilage-like repair that integrated with the surrounding cartilage better and higher cartilage extracellular matrix content. In conclusion, these results provide an alternative preparation method for drug-delivered SF microcarrier and a culture method for maintaining the chondrogenic phenotype of seed cells based on the microgravity environment. CTS showed its bioactive function, and the application of CTS-SF microcarriers can help repair and regenerate cartilage defects.

Uses, chemical compositions, pharmacological activities and toxicology of Clematidis Radix et Rhizome- a Review

ETHNOPHARMACOLOGICAL RELEVANCE

Clematis chinensis Osbeck (C. chinensis), Clematis hexapetala Pall (C. hexapetala) and Clematis terniflora var. mandshurica Rupr (C. mandshurica) are collectively referred to as Clematidis Radix et Rhizome (CRR) in China. CRR is widely distributed in China, which is used as a traditional Chinese medicine to treat rheumatic arthralgia, limb numbness, tendon constriction and inconvenience in flexion and extension.

AIMS OF THIS REVIEW

This review systematically summarized the research progress on uses, chemical components, pharmacological activities and toxicology of CRR, listed the chemical structures of main compounds for clarifying the differences in chemical compositions. Meanwhile, the review will provide a theoretical and practical basis for the further research and development of CRR.

MATERIALS AND METHODS

The available information on CRR was collected using published materials and electronic databases, including ancient and modern books, Chinese Pharmacopoeia, Ph.D. and M. Sc. dissertations, CNKI, SciFinder, WanFang data, PubMed, ScienceDirect and Web of Science. The starting and ending years of references is 1965-2020, the search strategy was conducted by key words such as uses, chemical components, pharmacology and toxicology of CRR.

RESULTS

Up to now, CRR has been used to treat various diseases/disorders, such as relieving rheumatism pain, treating cervical spondylopathy and scapulohumeral periarthritis, treating hepatic carcinoma and gastrointestinal, etc. In addition, more than 200 compounds have been isolated from the three plant species of Clematidis. Moreover, the crude extracts and isolated compounds of CRR have been reported to have a wide range of pharmacological activities, such as anti-inflammatory, anti-tumor, antimicrobial and antioxidant activities, etc. Toxicity studies have shown that CRR can cause oral burning, swelling, abdominal pain or severe diarrhea, difficulty breathing, dilated pupils, renal tissue structural changes, and severe death.

CONCLUSIONS

Researches in recent years mainly focused on C. chinensis and C. mandshurica, while there are a few reports on the pharmacological studies of C. hexapetala. Therefore, it is necessary to conduct further research on C. hexapetala. Meanwhile, it is important to pay attention to pursue research on the similarities and differences between the three plant species of Clematidis to find their respective advantages and make rational use of CRR. In addition, there is no report on the mechanism of toxicity research, which needs more attention.

Effects of Melatonin on Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells in Inflammatory Environment by Regulating Mammalian Target of Rapamycin/Phosphatidylinositol 3-Kinase/Protein Kinase B Signaling

Human bone marrow mesenchymal stem cells (BMSCs) differentiation into special cell types is affected by inflammation. Melatonin has various effects such as anti-oxidation and immune regulation. However, melatonin’s effect on BMSCs osteogenic differentiation during inflammation has not been elucidated. Rat BMSCs were isolated and assigned into control group, inflammation group (1 μg/ml lipopolysaccharide, LPS) and melatonin group (100 μM melatonin was added to LPSstimulated BMSCs cells) followed by analysis of BMSCs proliferation by MTT assay, Caspase 3 and ALP activity, expression of Runx2 and OP by Real time PCR, ROS content and SOD activity, TNF-α and IL-1β secretion by ELISA and mTOR/PI3K/AKT signaling protein level by Western blot. LPS action on BMSCs significantly inhibits BMSCs proliferation, promotes Caspase 3 activity, inhibits ALP activity, decreases Runx2 and OP expression and SOD activity, increases ROS content and TNF-α and IL-1β secretion as well as reduced mTOR and p-PI3K level (P <0.05). Melatonin addition significantly reversed the above changes (P <0.05). Melatonin can regulate oxidative stress, inhibit inflammation, and promote BMSCs proliferation and osteogenic differentiation in inflammatory environment by activating mTOR/PI3K/AKT signaling pathway.

Therapeutic Potential Low-Intensity Pulsed Ultrasound for Osteoarthritis: Pre-clinical and Clinical Perspectives

Osteoarthritis (OA), degeneration of cartilage associated with aging, lifestyle, and trauma, is one of the most common diseases that leads to lower quality of life and socioeconomic burden in the United States. Clinically, OA is initially managed by non-steroidal anti-inflammatory drugs, but eventually requires surgical intervention to reduce pain and increase function. Cartilage is a mechanotransductive tissue and requires a mechanical stimulus to sustain its mechanical and physiologic properties. Low-intensity pulsed ultrasound (LIPUS) is a cyclic acoustic wave that can provide essential mechanical stimuli to activate molecular and cellular pathways leading to chondrocyte proliferation, differentiation and activity, as well as to inhibit inflammatory pathways associated with OA. The activation of chondrocyte proliferation and inhibition of anti-inflammatory cytokines make LIPUS a potential therapy for mild to moderate OA. Although a few review articles have described the effects of ultrasound on chondrocytes and cartilage, there remains a need for a comprehensive analysis of our current understanding of the basic science and clinical status of the effects of low-intensity ultrasound on chondrocytes and cartilage and the implications of these studies on LIPUS as a therapeutic option for OA. This review analyzes recent literature describing the results of LIPUS using in vitro and in vivo pre-clinical models and clinical studies, as well as future directions for research.