Treatment Of Osteoarthritis Rats With Human Umbilical Cord Mesenchymal Stem Cells And Its Mechanism

Background:Osteoarthritis（OA）is a common chronic degenerative disease characterized by cartilage degeneration.It usually affects the entire joints and is one of the main causes of impaired body function and disability.It mainly affects articular cartilage.Bone and synovial tissue,causing joint pain,swelling and deformation,as well as bone hyperplasia.With the increasing understanding of the role of mesenchymal stem cells in tissue homeostasis and repair,scientists have concentrated on exploring the potential of stem cell therapy in the active treatment of osteoarthritis in recent years.The results of current preclinical and clinical trials have preliminarily proved that mesenchymal stem cell therapy is safe and effective in the treatment of knee arthritis.However,there are still many problems that need to be solved urgently in the treatment of osteoarthritis.The optimal timing of stem cell injection,the appropriate number of cells,the migration and survival time after injection into the knee joint both is unknown,also the mechanism of its therapeutic effect are still unconfirmed in the scientific community.ObjectiveThis article selects human umbilical cord mesenchymal stem cells（HUC-MSCs）for research,mainly to study the dose trend and the appropriate injection time of umbilical cord mesenchymal stem cells in the treatment of rat knee arthritis,and chose rats as the OA model to explores the survival time of mesenchymal stem cells in the joint cavity.In the supplementary experiment,the mouse OA model was used to observe the trace of HUC-MSCs in the joint cavity after injection.Method1.According to the current research status of mesenchymal stem cells,we design the experiments,adopt the rat medial meniscus instability（Destabilization of the medial meniscus,DMM）model for osteoarthritis model.2 and 4 weeks after modeling,we inject different doses of HUC-MSCs into the joint cavity of rats for treatment,and evaluate the treatment effect based on rat behavior,pathology and image compare with PBS vehicle;2.Construct GFP-expressing human umbilical cord mesenchymal stem cells（GFP-HUC-MSCs）and transplant them into the joint cavity of OA rats to track their survival time in vivo.In the supplementary experiment,OA mice were used to track the location of HUC-MSCs in the joint cavity after 24 hours.3.The synovial fluid of patients with OA knee replacement and the synovial fluid of patients with anterior cross reconstruction were collected.After dilution,HUC-MSCs were added to culture for 48 hours and then sent for sequencing to observe the changes of HUC-MSCs in the OA environment.Result1.The results of animal experiments show that both high and low dose HUC-MSCs treatment groups have a significant alleviation effect on rat knee joint pain and significantly reduce the Pelletier score of rat femur.Micro-CT shows that HUC-MSCs treatment can reduce the formation of OA osteophytes.The pathological results of Safranin-O fast green,HE,and histochemistry also showed that the HUC-MSCs treatment group can significantly reduce the pathological score compared with the vehicle group.2.HUC-MSCs carrying GFP were injected into the knee joint of rats for fluorescence tracking experiments.It was shown that HUC-MSCs can survive for nearly 4 weeks,and by the time,fluorescence signal become the weaker and weaker.This experiment shows that in the knee joint.HUC-MSCs Will be cleared by the body over time and gradually decrease.3.Supplementary experiments prove that HUC-MSCs mainly adhere to the synovial membrane,meniscus and medullary cavity after entering the joint cavity for 24 hours.