Chondroprotective Effects of Combination Therapy of Acupotomy and Human Adipose Mesenchymal Stem Cells in Knee Osteoarthritis Rabbits via the GSK3β-Cyclin D1-CDK4/CDK6 Signaling Pathway

Needle-scalpel therapy inhibits the apoptosis of nucleus pulposus cells via the SDF-1/CXCR4 axis in a rat degenerative cervical intervertebral disc model

As a common disease, cervical spondylosis (CS) results from the degeneration of the cervical intervertebral disc. However, there are still no effective clinical strategies for the treatment of this disease. Needle-scalpel (Ns), a therapy guided by traditional Chinese medicine theory, alleviates intervertebral disc degradation and is widely used in the clinic to treat CS. Stromal cell-derived factor-1 (SDF-1) and its receptor CXC receptor 4 (CXCR4) in nucleus pulposus cells play an important role in CS onset and development. This study aimed to explore whether Ns can relieve pain and regulate the SDF-1/CXCR4 axis in nucleus pulposus cells to inhibit apoptosis, thereby delaying cervical intervertebral disc degradation in a rat model of CS. It was found that the Ns-treated groups exhibited higher mechanical allodynia scores than the model group, and H&E staining, MRI, and scanning electron microscopy revealed that Ns therapy inhibited intervertebral disc degeneration. Additionally, Ns therapy significantly inhibited increases in the RNA and protein expression levels of SDF-1 and CXCR4. Furthermore, these treatments alleviated the apoptosis of nucleus pulposus cells, which manifested as a decline in the proportion of apoptotic nucleus pulposus cells and inhibition of the decrease in the levels of Bcl-2/Bax. These findings indicated that Ns mitigated CS-induced pain, inhibited the apoptosis of nucleus pulposus cells, and alleviated intervertebral disc degeneration in CS rats. These effects may be mediated by specifically regulating the SDF-1/CXCR4 signaling axis. Based on these findings, we conclude that Ns might serve as a promising therapy for the treatment of CS.

Acupotomy alleviates knee osteoarthritis in rabbit by regulating chondrocyte mitophagy Pink1-Parkin pathway

OBJECTIVE

To investigate the effect of acupotomy, on mitophagy and the Pink1-Parkin pathway in chondrocytes from rabbits with knee osteoarthritis (KOA).

METHODS

A KOA model was established via the modified Videman method. Rabbits were randomly divided into a control group (CON), KOA group and KOA + acupotomy group (Acu). Rabbits in the acupotomy group were subjected to acupotomy for 4 weeks after model establishment. The behavior of the rabbits before and after intervention was recorded. Cartilage degeneration was evaluated by optical microscopy and fluorescence microscopy. The level of mitophagy was evaluated by transmission electron microscopy, immunofluorescence and enzyme-linked immunosorbent assay (ELISA). The expression of phosphatase and tensin homolog (PTEN)-induced kinase 1 (Pink1)-Parkin mitophagy pathway components was evaluated by immunofluorescence, Western blotting and real-time polymerase chain reaction.

RESULTS

In rabbits with KOA, joint pain, mobility disorders and cartilage degeneration were observed, the Mankin score was increased, collagen type Ⅱ (Col-Ⅱ) expression was significantly decreased, mitophagy was inhibited, mitochondrial function was impaired, and factors associated with the Pink1-Parkin pathway were inhibited. Acupotomy regulated the expression of Pink1-Parkin pathway-related proteins, the mitophagy-related protein microtubule-associated protein-1 light chain-3, the translocase of the outer membrane, and the inner mitochondrial membrane 23; increased the colocalization of mitochondria and autophagosomes; promoted the removal of damaged mitochondria; restored mitochondrial adenosine-triphosphate (ATP) production; and alleviated cartilage degeneration in rabbits with KOA.

CONCLUSIONS

Acupotomy played a role in alleviating KOA in rabbits by activating mitophagy in chondrocytes via the regulation of proteins that are related to the Pink1-Parkin pathway.

Efficacy and immune-inflammatory mechanism of acupuncture-related therapy in animal models of knee osteoarthritis: a preclinical systematic review and network meta-analysis

BACKGROUND

Many KOA patients have not reached indications for surgery, thus we need to find effective non-surgical treatments. Acupuncture is thought to have the potential to modulate inflammation and cytokines in KOA through the immune system. However, the mechanisms have not been elucidated, and there is no network Meta-analysis of acupuncture on KOA animals. So we evaluate the effect and mechanism of acupuncture-related therapy in KOA animals.

METHODS

A comprehensive search was conducted in multiple databases including PubMed, Web of Science, Embase, CBM, CNKI, WanFang, and VIP Database to identify relevant animal studies focusing on acupuncture therapy for KOA. The included studies were assessed for risk of bias using SYRCLE's Risk of Bias tool. Subsequently, pair-wise meta-analysis and network meta-analysis were performed using Stata 15.0 software, evaluating outcomes such as Lequesne index scale, Mankin score, IL-1β, TNF-α, MMP3, and MMP13.

RESULTS

56 RCTs with 2394 animals were included. Meta-analysis showed that among the 6 outcomes, there were significant differences between acupuncture and model group; the overall results of network meta-analysis showed that the normal group or sham operation group performed the best, followed by the acupotomy, acupuncture, and medicine group, and the model group had the worst effect, and there were significant differences between 6 interventions.

CONCLUSIONS

Acupuncture-related therapy can be a possible treatment for KOA. The mechanism involves many immune-inflammatory pathways, which may be mediated by DAMPs/TLR/NF-κB/MAPK,PI3K/Akt/NF-κB pathway, or IFN-γ/JAK-STAT pathway. It needs to be further confirmed by more high-quality animal experiments or meta-analysis.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO identifier: CRD42023377228.

Acupotomy ameliorates subchondral bone absorption and mechanical properties in rabbits with knee osteoarthritis by regulating bone morphogenetic protein 2-Smad1 pathway

OBJECTIVE

To investigate the effects of acupotomy on the subchondral bone absorption and mechanical properties in rabbits with knee osteoarthritis (KOA).

METHODS

The rabbits were divided into blank control, model, acupotomy and electroacupuncture (EA) groups, with 12 rabbits in each. Modified Videman's method was used to prepare KOA model. The acupotomy and EA group were given indicated intervention for 3 weeks. The behavior of rabbits in each group was recorded. Subsequently, cartilage-subchondral bone units were obtained and morphological changes were observed by optical microscope and micro computed tomography. Compression test was used to detect the mechanical properties of subchondral bone, Western blot and real-time polymerase chain reaction (RT-PCR) were applied to detect the expression of bone morphogenetic protein 2-Smad1 (BMP2-Smad1) pathway in subchondral bone.

RESULTS

Compared with the control group, rabbits in the KOA group showed lameness, knee pain, and cartilage degradation; the subchondral bone showed active resorption, the mechanical properties decreased significantly and the BMP2-Smad1 pathway downregulated significantly. Both acupotomy and EA intervention could increase the thickness of trabecular bone (Tb. Th), the bone volume fraction (BV/TV) and the thickness of subchondral bone plate, reduce the separation of trabecular bone (Tb. Sp), improve the maximum load and elastic modulus of subchondral bone, and effectively delay cartilage degeneration in KOA rabbits. This process may be achieved through upregulation the related proteins of BMP2-Smad1 pathway. The maximum load and elastic modulus of subchondral bone in the acupotomy group were slightly better than those in the EA group.

CONCLUSIONS

Acupotomy could effectively protect cartilage by inhibiting abnormal bone resorption and improving mechanical properties of subchondral bone thorough the related proteins of BMP2-Smad1 pathway in KOA rabbits.

High expression of GPR50 promotes the proliferation, migration and autophagy of hepatocellular carcinoma cells in vitro

G protein-coupled receptors (GPCRs) play important roles in tumorigenesis and the development of hepatocellular carcinoma (HCC). GPR50 is an orphan GPCR. Previous studies have indicated that GPR50 could protect against breast cancer development and decrease tumor growth in a xenograft mouse model. However, its role in HCC remains indistinct. To detect the role and the regulation mechanism of GPR50 in HCC, GPR50 expression was analyzed in HCC patients (gene expression omnibus database (GEO) (GSE45436)) and detected in HCC cell line CBRH-7919, and the results showed that GPR50 was significantly up-regulated in HCC patients and CBRH-7919 cell line compared to the corresponding normal control. Gpr50 cDNA was transfected into HCC cell line CBRH-7919, and we found that Gpr50 promoted the proliferation, migration, and autophagy of CBRH-7919. The regulation mechanism of GPR50 in HCC was detected by isobaric tags for relative and absolute quantification (iTRAQ) analysis, and we found that GPR50 promoted HCC was closely related to CCT6A and PGK1. Taken together, GPR50 may promote HCC progression via CCT6A-induced proliferation and PGK1-induced migration and autophagy, and GPR50 could be an important target for HCC.

Cartilage regeneration and inflammation modulation in knee osteoarthritis following injection of allogeneic adipose-derived mesenchymal stromal cells: a phase II, triple-blinded, placebo controlled, randomized trial

BACKGROUND

Intra-articular injection of mesenchymal stromal cells (MSCs) with immunomodulatory features and their paracrine secretion of regenerative factors proposed a noninvasive therapeutic modality for cartilage regeneration in knee osteoarthritis (KOA).

METHODS

Total number of 40 patients with KOA enrolled in two groups. Twenty patients received intra-articular injection of 100 × 10⁶ allogeneic adipose-derived mesenchymal stromal cells (AD-MSCs), and 20 patients as control group received placebo (normal saline). Questionnaire-based measurements, certain serum biomarkers, and some cell surface markers were evaluated for 1 year. Magnetic resonance imaging (MRI) before and 1 year after injection was performed to measure possible changes in the articular cartilage.

RESULTS

Forty patients allocated including 4 men (10%) and 36 women (90%) with average age of 56.1 ± 7.2 years in control group and 52.8 ± 7.5 years in AD-MSCs group. Four patients (two patients from AD-MSCs group and two patients from the control group) excluded during the study. Clinical outcome measures showed improvement in AD-MSCs group. Hyaluronic acid and cartilage oligomeric matrix protein levels in blood serum decreased significantly in patients who received AD-MSCs (P < 0.05). Although IL-10 level significantly increased after 1 week (P < 0.05), the serum level of inflammatory markers dramatically decreased after 3 months (P < 0.001). Expressions of CD3, CD4, and CD8 have a decreasing trend during 6-month follow-up (P < 0.05), (P < 0.001), and (P < 0.001), respectively. However, the number of CD25⁺ cells increased remarkably in the treatment group 3 months after intervention (P < 0.005). MRI findings showed a slight increase in the thickness of tibial and femoral articular cartilages in AD-MSCs group. The changes were significant in the medial posterior and medial anterior areas of ​​the tibia with P < 0.01 and P < 0.05, respectively.

CONCLUSION

Inter-articular injection of AD-MSCs in patients with KOA is safe. Laboratory data, MRI findings, and clinical examination of patients at different time points showed notable articular cartilage regeneration and significant improvement in the treatment group.

TRIAL REGISTRATION

Iranian registry of clinical trials (IRCT, https://en.irct.ir/trial/46 ), IRCT20080728001031N23. Registered 24 April 2018.

[Electroacupuncture improves motor function of rats with osteoarthritis by alleviating joint inflammation through the Wnt-7B/β-catenin signaling pathway]

OBJECTIVE

To investigate the effect of electroacupuncture on osteoarthritis in rats and explore the possible mechanism.

METHODS

Thirty SD rats were randomly divided into osteoarthritis model group, electro-acupuncture group and control group (n=10), and in the former two groups, early osteoarthritis was induced using a modified DMM surgical modeling method. After successful modeling, the rats in the electro-acupuncture group were treated with electro-acupuncture at bilateral "Housanli" and "Anterior knee point". Behavioral tests of the rats were performed and scored using the LequesneMG scale. Subchondral bone degeneration was observed in each group, and serum levels of IL-1β, ADAMTS-7, MMP-3 and COMP were measured using ELISA. The mRNA and protein expressions of IL-1β, Wnt-7B, β-catenin, ADAMTS-7, and MMP-3 in the cartilage tissue of the knee joints were detected using RT-PCR and Western blotting.

RESULTS

In behavioral tests, the rats in the model and electroacupuncture groups had significantly higher LequesneMG scores after modeling than those in the control group (P < 0.05). After 20 days of treatment, LequesneMG scores were significantly lowered in rats in the electroacupuncture as compared with the model rats (P < 0.05). Imaging examination revealed obvious subchondral bone damage in both the electroacupuncture group and the model group, but the damages were significantly milder with former group. Compared with the model rats, the rats receiving electroacupuncture had significantly lower serum levels of IL-1β, ADAMTS-7, MMP-3 and COMP (P < 0.05) with also lower expressions of IL-1β, Wnt-7B, β-catenin, ADAMTS-7 and MMP-3 in the cartilage tissues at both the mRNA and protein levels (P < 0.05).

CONCLUSION

Electroacupuncture can alleviate joint pain and improve subchondral bone damage in rats with osteoarthritis by reducing IL-1β levels in the joint cartilage tissue and serum to alleviate joint inflammation and by reducing such cytokines as ADAMTS-7 and MMP-3 via regulating the Wnt-7B/β-catenin signaling pathway.

Matrix Stiffness Activating YAP/TEAD1-Cyclin B1 in Nucleus Pulposus Cells Promotes Intervertebral Disc Degeneration

Intervertebral disc degeneration is a leading cause of disability in the elderly population. Rigid extracellular matrix is a critical pathological feature of disc degeneration, leading to aberrant nucleus pulposus cells (NPCs) proliferation. However, the underlying mechanism is unclear. Here, we hypothesize that increased matrix stiffness induces proliferation and thus degenerative phenotypes of NPCs through YAP/TEAD1 signaling pathway. We established hydrogel substrates to mimic stiffness of degenerated human nucleus pulposus tissues. RNA-sequencing identified differentially expressed genes between primary rat NPCs cultured on rigid and soft hydrogels. Dual luciferase assay and gain- and loss-function experiments evaluated the correlation between YAP/TEAD1 and Cyclin B1. Furthermore, single-cell RNA-sequencing of human NPCs was performed to identify specific cell clusters with high YAP expression. Matrix stiffness increased in severely degenerated human nucleus pulposus tissues (p < 0.05). Rigid substrate enhanced rat NPCs proliferation mainly through Cyclin B1, which was directly targeted and positively regulated by YAP/TEAD1. Depletion of YAP or Cyclin B1 arrested G2/M phase progression of rat NPCs and reduced fibrotic phenotypes including MMP13 and CTGF (p < 0.05). Fibro NPCs with high YAP expression were identified in human tissues and responsible for fibrogenesis during degeneration. Furthermore, inhibition of YAP/TEAD interaction by verteporfin suppressed cell proliferation and alleviated degeneration in the disc needle puncture model (p < 0.05). Our results demonstrate that elevated matrix stiffness stimulates fibro NPCs proliferation through YAP/TEAD1-Cyclin B1 axis, indicating a therapeutic target for disc degeneration.

Cell-based therapies have disease-modifying effects on osteoarthritis in animal models. A systematic review by the ESSKA Orthobiologic Initiative. Part 1: adipose tissue-derived cell-based injectable therapies

PURPOSE

The aim of this systematic review was to determine if adipose tissue-derived cell-based injectable therapies can induce disease-modifying effects in joints affected by osteoarthritis (OA).

METHODS

A systematic review was performed on three electronic databases (PubMed, Web of Science, Embase) according to PRISMA guidelines. A synthesis of the results was performed investigating disease-modifying effects in preclinical studies comparing injectable adipose-derived products with OA controls or other products, different formulations or injection intervals, and the combination with other products. The risk of bias was assessed according to the SYRCLE's tool.

RESULTS

Seventy-one studies were included (2,086 animals) with an increasing publication trend over time. Expanded cells were used in 65 studies, 3 studies applied point of care products, and 3 studies investigated both approaches. Overall, 48 out of 51 studies (94%) reported better results with adipose-derived products compared to OA controls, with positive findings in 17 out of 20 studies (85%) in macroscopic, in 37 out of 40 studies (93%) in histological, and in 22 out of 23 studies (96%)  in immunohistochemical evaluations. Clinical and biomarker evaluations showed positive results in 14 studies out of 18 (78%) and 12 studies out of 14 (86%), while only 9 studies out of 17 (53%) of the imaging evaluations were able to detect differences versus controls. The risk of bias was low in 38% of items, unclear in 51%, and high in (11%).

CONCLUSION

The current preclinical models document consistent evidence of disease-modifying effects of adipose-derived cell-based therapies for the treatment of OA. The high heterogeneity of the published studies highlights the need for further targeted research to provide recommendations on the optimal methodologies for a more effective application of these injective therapies for the treatment of OA in clinical practice.

LEVEL OF EVIDENCE

II.

Proteomic Analyses Reveals the Mechanism of Acupotomy Intervention on the Treatment of Knee Osteoarthritis in Rabbits

Acupotomy intervention (AI) is an available treatment for knee osteoarthritis (KOA) in China, which is a common health problem over the world. However, the underlying mechanism of AI on the KOA treatment is still unknown. To further understand the mechanism of acupotomy in treating KOA, the morphological observation and TMT proteomic analyses were conducted in rabbits. By using X-ray and MRI, we found that the space of the knee joint was bigger in AI than in KOA. Moreover, the chondrocytes were neatly arranged in AI but disordered in KOA. With proteomic analyses in chondrocytes, 68 differently accumulated proteins (DAPs) were identified in AI vs. KOA and DAPs related to energy metabolism and the TCA cycle were suggested to play a central role in response to AI. Furthermore, AIFM1 was proposed to be an important regulator in controlling the energy production in mitochondrial. Besides, FN1, VIM, COL12A1, COL14A1, MYBPH, and DPYSL3 were suggested to play crucial roles in AI for the treatment of KOA. Our study was systematically elucidating the regulation mechanism of acupotomy intervention in the treatment of KOA.

Mesenchymal stromal cell-based therapy for cartilage regeneration in knee osteoarthritis

Osteoarthritis, as a degenerative disease, is a common problem and results in high socioeconomic costs and rates of disability. The most commonly affected joint is the knee and characterized by progressive destruction of articular cartilage, loss of extracellular matrix, and progressive inflammation. Mesenchymal stromal cell (MSC)-based therapy has been explored as a new regenerative treatment for knee osteoarthritis in recent years. However, the detailed functions of MSC-based therapy and related mechanism, especially of cartilage regeneration, have not been explained. Hence, this review summarized how to choose, authenticate, and culture different origins of MSCs and derived exosomes. Moreover, clinical application and the latest mechanistical findings of MSC-based therapy in cartilage regeneration were also demonstrated.

Effectiveness and safety of acupotomy for knee osteoarthritis: study protocol for a randomized controlled trial

Background

Knee osteoarthritis (KOA) is one of the most common musculoskeletal disorders. Acupotomy may be effective for KOA, but the evidence is limited. This trial aims to determine the effectiveness and safety of acupotomy for KOA.

Methods/design

This is a parallel-group, assessor-blinded randomized controlled trial. Two hundred patients with KOA will be recruited and randomly assigned to two groups (group A or group D) in a 1:1 ratio. Patients in group A will receive acupotomy and topical diclofenac diethylamine for 4 weeks, while patients in group D will receive topical diclofenac diethylamine alone for 4 weeks. The primary outcome will be the response rate—the proportion of patients who achieve the minimal clinically important improvement in pain and function at week 4 compared with baseline. Secondary outcomes will include pain, function, quality of life, the use of rescue medicine (loxoprofen sodium), and adverse events at weeks 4, 8, and 24 after randomization. Besides, joint fluid and serum will be collected to assess the level of inflammatory cytokines, like TNF-α, IL-1β, and MMP-3.

Discussion

This study will contribute to a better understanding of the effectiveness and safety of acupotomy in combination with topical nonsteroidal anti-inflammatory drugs. If the hypothesis is confirmed, acupotomy may be recommended as adjunctive therapy for patients with KOA. Results of the study will be of great importance for the guidelines of clinical therapy.

Trial registration

Chinese Clinical Trial Registry ChiCTR2100043005 Registered on 4 February 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05786-5.

Human Adipose Mesenchymal Stem Cell-derived Exosomes Protect Mice from DSS-Induced Inflammatory Bowel Disease by Promoting Intestinal-stem-cell and Epithelial Regeneration

Inflammatory bowel disease (IBD) remains a severe disease for most patients, with its incidence and prevalence increasingly globally. Currently, there is no effective treatments for IBD, and traditional treatments have multiple side effects. Therefore, novel therapeutic strategies or alternative drugs are urgently needed. Previous studies have shown that mesenchymal stem cell-derived exosomes have exhibited promising therapeutic effects on inflammatory disease. Here, we performed intravenous injection of human adipose mesenchymal stem cell (hADSC)-derived exosomes (hADSC-Exo) in a DSS-induced IBD mouse model and found that hADSC-Exo promoted functional recovery, downregulated inflammatory responses, reduced intestine cell apoptosis, increased epithelial regeneration and maintained intestinal barrier integrity. Moreover, we established a colon organoid, hADSC-Exo and TNF-α co-cultured system to explore the protective effect of hADSC-Exo on integrity of intestine mucosa and epithelial regeneration. We showed that hADSC-Exo not only can promote the proliferation and regeneration of Lgr5⁺ ISCs and epithelial cells but also ameliorate the inflammation damage in TNF-α induced inflammatory damaged mice colon organoids. Taken together, our findings indicate that hADSC-Exo protects intestine integrity, activates intestine epithelial cell and ISCs proliferation, suggesting that hADSC-Exo might be a potential effective treatment approach for IBD. We also provide a theoretical basis for new therapeutic strategies for cell-free therapy in inflammatory bowel disease.

Effect of Warm Acupuncture Combined with Bone Marrow Mesenchymal Stem Cells Transplantation on Cartilage Tissue in Rabbit Knee Osteoarthritis

The current study was designed to investigate the effect and underlying mechanism of warm acupuncture combined with bone marrow mesenchymal stem cells (BMSC) transplantation on cartilage tissue injury in rabbit knee osteoarthritis (KOA). In the study, 50 rabbits were randomly divided into 5 groups: blank group, KOA group, warm acupuncture group, BMSCs group, and warm acupuncture combined with BMSCs group. After warm acupuncture combined with BMSCs, the Modified Lequesne MG knee joint assessment scale was used to evaluate the degree of knee joint behavior, the Taiping Peng method generally observed the histomorphology changes of KOA rabbit cartilage, and hematoxylin-eosin staining, safranin O green staining, and toluidine blue staining were conducted to evaluate the extent of cartilage tissue pathology. Furthermore, transmission electron microscopy and TUNEL staining were used to observe cell apoptosis, and immunohistochemistry and qPCR analysis were used to detect the expression of apoptosis-related proteins and mRNA. Results showed that administration of warm acupuncture combined with BMSCs recovered the joint function and significantly decreased Lequesne MG score. The degree of cartilage tissue pathological damage has been improved, cartilage ultrastructure degeneration has recovered, peripheral blood vessels have mild edema, blood supply has gradually recovered, and even small amounts of red blood cells have appeared. In addition, warm acupuncture combined with BMSCs treatment suppressed chondrocyte apoptosis in rabbits with knee osteoarthritis by reduced TUNEL-positive chondrocytes and simultaneously reversed the mRNA expression of Bax, Bcl-2, and Caspase-3. These results indicate that warm acupuncture combined with BMSCs transplantation has a potential protective effect on rabbit KOA, which may be mediated by inhibiting chondrocyte apoptosis.

Acupotomy Contributes to Suppressing Subchondral Bone Resorption in KOA Rabbits by Regulating the OPG/RANKL Signaling Pathway

Subchondral bone lesions, as the crucial inducement for accelerating cartilage degeneration, have been considered as the initiating factor and the potential therapeutic target of knee osteoarthritis (KOA). Acupotomy, the biomechanical therapy guided by traditional Chinese meridians theory, alleviates cartilage deterioration by correcting abnormal mechanics. Whether this mechanical effect of acupotomy inhibits KOA subchondral bone lesions is indistinct. This study aimed to investigate the effects of acupotomy on inhibiting subchondral bone resorption and to define the possible mechanism in immobilization-induced KOA rabbits. After KOA modeling, 8 groups of rabbits (4w/6w acupotomy, 4w/6w electroacupuncture, 4w/6w model, and 4w/6w control groups) received the indicated intervention for 3 weeks. Histological and bone histomorphometry analyses revealed that acupotomy prevented both cartilage surface erosion and subchondral bone loss. Further, acupotomy suppressed osteoclast activity and enhanced osteoblast activity in KOA subchondral bone, showing a significantly decreased expression of tartrate-resistant acid phosphatase (TRAP), matrix metalloproteinases-9 (MMP-9), and cathepsin K (Ctsk) and a significantly increased expression of osteocalcin (OCN); this regulation may be mediated by blocking the decrease in osteoprotegerin (OPG) and the increase in NF-κB receptor activated protein ligand (RANKL). These findings indicated that acupotomy inhibited osteoclast activity and promoted osteoblast activity to ameliorate hyperactive subchondral bone resorption and cartilage degeneration in immobilization-induced KOA rabbits, which may be mediated by the OPG/RANKL signaling pathway. Taken together, our results indicate that acupotomy may have therapeutic potential in KOA by restoring the balance between bone formation and bone resorption to attenuate subchondral bone lesions.