Connective Tissue Research最新文献

Purpose/aim: Cartilage injury and subsequent osteoarthritis (OA) are debilitating conditions affecting millions worldwide. As there are no cures for these ailments, novel therapies are needed to suppress disease pathogenesis. Given that joint injuries are known to produce damage-associated molecular patterns (DAMPs), our central premise is that the Toll-like receptor 4 (TLR4) pathway is a principal driver in the early response to cartilage damage and subsequent pathology. We postulate that TLR4 activation is initiated/perpetuated by DAMPs released following joint damage. Thus, antagonism of the TLR4 pathway immediately after injury may suppress the development of joint surface defects.

Materials and methods: Two groups were utilized: (1) 8-week-old, male C57BL6 mice treated systemically with a known TLR4 antagonist and (2) mice injected with vehicle control. A full-depth cartilage lesion on the midline of the patellofemoral groove was created in the right knee of each mouse. The left knee was used as a sham surgery control. Gait changes were evaluated over 4 weeks using a quantitative gait analysis system. At harvest, knee joints were processed for pathologic assessment, Nanostring® transcript expression, and immunohistochemistry (IHC).

Results: Short-term treatment with a TLR4 antagonist at 14-days significantly improved relevant gait parameters; improved cartilage metrics and modified Mankin scores were also seen. Additionally, mRNA expression and IHC showed reduced expression of inflammatory mediators in animals treated with the TLR4 antagonist.

Conclusions: Collectively, this work demonstrates that systemic treatment with a TLR4 antagonist is protective to further cartilage damage 14-days post-injury in a murine model of induced disease.

Purpose/aim of the study: To summarize and discuss macrophage properties and their roles and mechanisms in the process of osseointegration in a comprehensive manner, and to provide theoretical support and research direction for future implant surface modification efforts.

Materials and methods: Based on relevant high-quality articles, this article reviews the role of macrophages in various stages of osseointegration and methods of implant modification.

Results and conclusions: Macrophages not only promote osseointegration through immunomodulation, but also secrete a variety of cytokines, which play a key role in the angiogenic and osteogenic phases of osseointegration. There is no "good" or "bad" difference between the M1 and M2 phenotypes of macrophages, but their timely presence and sequential switching play a crucial role in implant osseointegration. In the implant surface modification strategy, the induction of sequential activation of the M1 and M2 phenotypes of macrophages is a brighter prospect for implant surface modification than inducing the polarization of macrophages to the M1 or M2 phenotypes individually, which is a promising pathway to enhance the effect of osseointegration and increase the success rate of implant surgery.

Purpose: This study aims to evaluate the reliability and validity of using MyotonPRO to quantify the mechanical properties of the muscle-tendon unit through in vivo measurements and preliminary in situ measurements using formalin-fixed tissues.

Materials and methods: The mechanical properties of gastrocnemii and the Achilles tendon of 12 healthy adults (six males and six females, 34.9 ± 5.8 years) were examined for in vivo test twice within a day and once post-24 hours using MyotonPRO, while nine human cadavers (formalin-fixed, 3 males and 6 females, 89.9 ± 5.1 years) were assessed for preliminary in situ test with identical time schedule to evaluate the within-day and inter-day reliability and validity.

Results: In vivo tests had very high within-day (ICC: 0.96-0.99) and inter-day reliability (ICC: 0.83-0.96), while in situ tests (formalin-fixed tissues) showed high within-day (ICC: 0.87-0.99) and inter-day reliability (ICC: 0.76-0.98) for the results of tone and stiffness. There was no significant difference in the stiffness of the free part of the Achilles tendon between in vivo and in situ conditions. The stiffness of the lateral gastrocnemius (r = 0.55, p = 0.018), proximal part of the Achilles tendon (r = 0.56, p = 0.015), and free part of the Achilles tendon (r = 0.47, p = 0.048) before removing the skin was significantly correlated with that after removing the skin condition.

Conclusions: The findings of the current study suggest that MyotonPRO is reliable and valid for evaluating tendon stiffness both in vivo and in situ (formalin-fixed tissues).

The pivotal role of lncRNAs in osteoporosis progression and development necessitates a comprehensive exploration of the functional and precise molecular mechanisms underlying lncRNA SNHG1's regulation of osteoblast differentiation and calcification. The study involved inducing BMSCs cells to differentiate into osteoblasts, followed by transfections of miR-497-5p inhibitors, pcDNA3.1-SNHG1, sh-HIF1AN, miR-497-5p mimics, and respective negative controls into BMSCs. Quantitative PCR (qPCR) was employed to assess the expression of SNHG1 and miR-497-5p. Western Blotting was conducted to measure the levels of short stature-related transcription factor 2 (RUNX2), osteopontin (OPN), osteocalcin (OCN), and HIF1AN. Alkaline phosphatase (ALP) activity was determined using appropriate assay kits. Calcium nodule staining was performed through Alizarin red staining. Dual luciferase reporter gene assays were executed to validate the interaction between SNHG1 and miR-497-5p, as well as HIF1AN. Throughout osteogenic differentiation, there was a down-regulation of SNHG1 and HIF1AN, in contrast to an elevation in miR-497-5p levels. Direct interactions between miR-497-5p and both SNHG1 and HIF1AN were observed. Notably, SNHG1 exhibited the ability to modulate HIF1AN by influencing miR-497-5p, thereby inhibiting osteogenic differentiation. Functioning as a competitive endogenous RNA, lncRNA SNHG1 exerts an inhibitory influence on osteogenic differentiation via the miR-497-5p/HIF1AN axis. This highlights the potential for lncRNA SNHG1 to emerge as a promising therapeutic target for osteoporosis. The study's findings pave the way for a novel target strategy in the future treatment of osteoporosis.

Purpose/aim of the study: Curcumin is the active substance of turmeric and has been shown to enhance the healing potential of burn wounds. However, its high hydrophobicity and rapid degradability are great challenges for its clinical applications. The development of new curcumin formulations may provide a potential solution to these issues.

Methods and results: In this study, we investigated the use of curcumin nanomicelles for wound dressing and evaluated their effects on fibroblast migration and proliferation in vitro. We found that the application of curcumin nanomicelles to the wounds significantly improved wound contraction and increased the expression of transforming growth factor-1 and basic fibroblast growth factor at day 14 of the healing process. Furthermore, curcumin nanomicelles reduced the expression of interleukin-1 at days 7 and 14 post-wounding. Histopathological analysis revealed that the curcumin nanomicelles-treated burn wounds exhibited more organized granulation tissue, improved angiogenesis, and enhanced re-epithelialization. Additionally, the curcumin treatment led to increased hydroxyproline content and enhanced TGF-β1 expression level in the wounds. The in vitro studies also demonstrated that the curcumin nanomicelles induced proliferation and migration of fibroblasts.

Conclusion: Overall, our findings suggest that curcumin nanomicelles can be a promising candidate for the treatment of burn wounds.

Purpose: Ultrashort wave diathermy (USWD) is commonly used in diseases associated with osteoarticular and soft tissue injuries. However, while accelerating wound healing and preventing joint stiffness, there have been few reports on whether it leads to excessive hypertrophic scarring. The aim was to investigate the effects of different doses of USWD on hypertrophic scars.

Materials and methods: A rabbit model of hypertrophic scars was used to determine which dose of USWD reduced scar hyperplasia. The scar thickness was calculated using Sirius red staining. All protein expression levels were determined by western blotting, including fibrosis, collagen deposition, and neoangiogenesis related proteins. Subsequently, flow cytometry and ELISAs were used to determine the proportions of macrophage and inflammatory levels.

Results: The wounds with USWD in histopathology showed the dermis was more markedly thickened in the 120 mA group, whereas the wounds with the 60 mA were less raised, comparing with the 0 mA; all detected protein levels were increased significantly, the 120 mA group comparing with the others, including heat shock, fibrosis, and neoangiogenesis, whereas the collagen deposition relative protein levels were decreased, the 60 mA group comparing with Sham group; Finally, in the proportion of macrophages and inflammatory levels the 120 mA group were the highest, and the group Sham was lower than group 60 mA.

Conclusions: In hypertrophic scars, the 60 mA USWD could relieve scar formation and inflammatory reactions; however, higher doses could result in opposite consequences.

Purpose: Joint contractures after anterior cruciate ligament (ACL) reconstruction are a serious problem. Given the uncertain effects of weight bearing after ACL reconstruction on contractures, this study was conducted to examine such effects.

Materials and methods: To control the amount of weight bearing, ACL-reconstructed rats were reared with either untreated (small weight bearing; weight bearing during locomotion was 54% of pre-surgery at minimum), hindlimb unloading (non-weight bearing), or sustained morphine administration (large weight bearing; weight bearing during locomotion was maintained at 80% or more of pre-surgery) conditions. Untreated rats were used as controls. Knee extension range of motions (ROMs) before (includes myogenic and arthrogenic factors) and after myotomy (includes arthrogenic factor only) and fibrotic reactions in the joint capsule were assessed 7 and 14 days post-surgery.

Results: ACL reconstruction significantly reduced ROMs both before and after myotomy and induced fibrosis in the joint capsule accompanying upregulation of fibrosis-related genes (i.e., type I and III collagens and transforming growth factor-β1) at both time points. Morphine administration increased the ROM before myotomy, but not after myotomy 7 days post-surgery. Unloading after ACL reconstruction improved ROMs both before and after myotomy at both time points. In addition, unloading after ACL reconstruction attenuated fibrotic reactions in the joint capsule.

Conclusions: Our results suggest that morphine administration improves myogenic contractures in parallel with an increase in the amount of weight bearing. Unloading after ACL reconstruction is effective in reducing both myogenic and arthrogenic contractures.

Background: DICER1-AS1 is reported to promote the progression and disturb the cell cycle in osteosarcoma; however, its mechanism has rarely been studied.

Materials and methods: DICER1-AS1 expression levels were evaluated by qPCR and fluorescence in situ hybridization (FISH). The total, nuclear, and cytosolic levels of CDC5L were measured by western blotting and immunofluorescence (IF). Cell proliferation, apoptosis, and cell cycle analyses were conducted using the colony formation, CCK-8 assay, terminal transferase-mediated UTP nick end-labeling kit (TUNEL) assay, and flow cytometry. Levels of cell proliferation-, cell cycle-, and cell apoptosis-related proteins were determined by western blotting. RNA immunoprecipitation (RIP) and RNA pull-down assays were conducted to evaluate the relationship between DICER1-AS1 and CDC5L.

Results: LncRNA DICER1-AS1 was highly expressed in samples of osteosarcoma tissue and in osteosarcoma cell lines. DICER1-AS1 knockdown inhibited cell proliferation, promoted cell apoptosis, and disturbed the cell cycle. Moreover, DICER1-AS1 was found to bind with CDC5L, and knockdown of DICER-AS1 inhibited the nuclear transfer of CDC5L. DICER1-AS1 knockdown also reversed the effects of CDC5L overexpression on cell proliferation, apoptosis, and the cell cycle. Moreover, CDC5L inhibition suppressed cell proliferation, promoted cell apoptosis, and disturbed the cell cycle, and those effects were further enhanced by DICER1-AS1 knockdown. Finally, DICER1-AS knockdown inhibited tumor growth and proliferation, and promoted cell apoptosis in vivo.

Conclusion: LncRNA DICER1-AS1 knockdown inhibits the nuclear transfer of CDC5L protein, arrests the cell cycle, and induces apoptosis to suppress the development of osteosarcoma. Our results suggest a novel target (DICER1-AS1) for treatment of osteosarcoma.

Aim of the study: To investigate the role of MetaLnc9 in the osteogenesis of human bone marrow mesenchymal stem cells (hBMSCs).

Materials and methods: We used lentiviruses to knockdown or overexpress MetaLnc9 in hBMSCs. qRT-PCR was employed to determine the mRNA levels of osteogenic-related genes in transfected cells. ALP staining and activity assay, ARS staining and quantification were used to identify the degree of osteogenic differentiation. Ectopic bone formation was conducted to examine the osteogenesis of transfected cells in vivo. AKT pathway activator SC-79 and inhibitor LY294002 were used to validate the relationship between MetaLnc9 and AKT signaling pathway.

Results: The expression of MetaLnc9 was significantly upregulated in the osteogenic differentiation of hBMSCs. MetaLnc9 knockdown inhibited the osteogenesis of hBMSCs, whereas overexpression of it promoted the osteogenic differentiation both in vitro and in vivo. Taking a deeper insight, we found that MetaLnc9 enhanced the osteogenic differentiation by activating AKT signaling. The inhibitor of AKT signaling LY294002 could reverse the positive effect on osteogenesis brought by MetaLnc9 overexpression, whereas the activator of AKT signaling SC-79 could reverse the negative effect caused by MetaLnc9 knockdown.

Conclusion: Our works uncovered a vital role of MetaLnc9 in osteogenesis via regulating the AKT signaling pathway. [Figure: see text].