Anterior cruciate ligament is the most important ligament to maintain the anterior and rotation stability of knee joint. Rupture of anterior cruciate ligament is one of the most common injuries of knee joint, and thus leads to knee instability and traumatic osteoarthritis. Anterior cruciate ligament reconstruction is usually performed to restore the anterior stability of knee joint, and is considered to reduce the secondary injury of medial meniscus, lateral meniscus and cartilage. Thus anterior cruciate ligament reconstruction can improve the function of knee joint. Traditional single bundle technique to reconstruct anterior cruciate ligament has been performed for many years. This technique can restore the anterior stability of knee joint and has excellent clini?cal results. Nearly 61%patients showed obvious radiographic osteoarthritis 20 years after anterior cruciate ligament reconstruction using bone-patella-bone graft. But, there is no agreement regarding to reduce the development of osteoarthritis after reconstruc?tion of anterior cruciate ligament. However, it has been reported that osteoarthritis would develop after reconstruction of anterior cruciate ligament in long term follow up study. Recently, with the further understanding of anatomy of biomechanics of anterior cru?ciate ligament, new techniques for anterior cruciate ligament reconstruction are developed, such as double bundle reconstruction, anatomic reconstruction and individual reconstruction. It remains controversial that whether these new technique can prevent the development of osteoarthritis after rupture of anterior cruciate ligament. Currently, no reconstruction technique for anterior cruci?ate ligament is perfect, and every technique has advantages and disadvantages. In terms of reducing the prevalence of osteoarthri?tis after reconstruction of anterior cruciate ligament, which technique is the best still remains unclear. New treatment and evalua?tion methods should be developed. In the future, not only the restoration of stability of knee joint should be considered, but also the articular cartilage contact kinematics including tibiofemoral joint and patellofemoral joint after anterior cruciate ligament recon?struction. Reduction of the development of osteoarthritis is an important topic after reconstruction of anterior cruciate ligament.

BACKGROUND:Satellite cells are myogenic stem cells located between the muscle fiber membrane and the basement membrane.However,a comprehensive review of the aging mechanisms of satellite cells and their potential mitigation strategies is still lacking.This gap in knowledge hinders the effective guidance for current strategies aimed at attenuating skeletal muscle aging. OBJECTIVE:To review the mechanisms of satellite cell aging in skeletal muscle and the relevant strategies for mitigating this aging process. METHODS:Major databases were searched up to May 2023,including Web of Science,PubMed,China National Knowledge Infrastructure(CNKI),WanFang Data,and VIP.Chinese and English search terms included"skeletal muscle,satellite cells,aging,mechanism,and solution strategy".After strict inclusion and exclusion criteria were applied,78 articles were finally included. RESULTS AND CONCLUSION:(1)Satellite cells,situated between the muscle fiber membrane and basement membrane,possess proliferative and differentiative potential.They usually remain in a quiescent state but become activated in response to muscle tissue stimuli,participating in processes of repair and restoration of normal tissue structure.Aging leads to a reduction in satellite cell numbers,resulting in symptoms such as muscle weakness and decreased endurance.(2)Mechanisms of satellite cell aging primarily involve diminished regenerative capacity,perturbed niche interactions with changing ecology,age-dependent loss,and heterogeneity changes.Reduced satellite cell numbers and activity due to aging lead to slower muscle regeneration and increased injury recovery time.Errors during differentiation may occur,resulting in decreased muscle quality and function deterioration.(3)Strategies for mitigating satellite cell aging encompass modulation of the receptor environment of intra-body satellite cells,peripheral interventions to promote satellite cell regeneration,construction of human muscle models,and exercise and nutritional interventions to induce satellite cell proliferation.These strategies hold promise in offering novel insights and methods for satellite cell regeneration and treatment of skeletal muscle diseases.(4)Future research should delve into the mechanisms of satellite cell aging,explore the interaction between satellite cells and their niches,investigate the relationship of satellite cells with the immune system and mitochondrial function,and develop human muscle models to enhance research depth and accuracy.

Background and Objectives: Human umbilical cord mesenchymal stem cells (HUC-MSCs) are promising candidates for cell-based therapy in regenerative medicine or other diseases due to their superior characteristics, including higher proliferation, faster self-renewal ability, lower immunogenicity, a noninvasive harvest procedure, easy expansion in vitro, and ethical access, compared with stem cells from other sources. Methods: and Results: In the present study, we knocked down the expression of SOX9 in HUC-MSCs by lentivirus interference and found that knockdown of SOX9 inhibited the proliferation and migration of HUC-MSCs and influenced the expression of cytokines (IL-6 and IL-8), growth factors (GM-CSF and VEGF) and stemness-related genes (OCT4 and SALL4). In addition, the repair effect of skin with burn injury in rats treated with HUC-MSCs transfected with sh-control was better than that rats treated with HUC-MSCs transfected with shSOX9 or PBS, and the accessory structures of the skin, including hair follicles and glands, were greater than those in the other groups. We found that knockdown of the expression of SOX9 obviously inhibited the expression of Ki67, CK14 and CK18. Conclusions In conclusion, this study will provide a guide for modifying HUC-MSCs by bioengineering technology in the future.