Synthesis Of Nano-drug-loaded System Encapsulating Anti-Inflammatory Drugs And Cartilage Inducing Factors And Preliminary Observation Of The Therapeutic Effect In The Treatment Of Rheumatoid Arthritis

Background: Rheumatoid arthritis(RA)is a chronic inflammatory autoimmune disease characterized by synovial hyperplasia and destruction of articular cartilage.It often involves the small joints of the extremities such as the hands and feet,and the late stage seriously affects joint function and quality of life.Existing research suggests that inflammation and cartilage destruction in affected joints of RA patients are mainly caused by cytokines and matrix metalloproteinases(MMPs)released by macrophages and neutrophils that invade joint synovium.Among the many MMPs,the most concerned are MMP-2 and MMP-9.They overproduce and activate in the affected joints and carry out cartilage destruction by directly degrading the cartilage matrix.The inflammation of RA is mainly caused by inflammatory cytokines,such as Tumor Necrosis Factor?(TNF-?)and Interleukin-6(IL-6).With the recognition that intracellular kinase signaling pathways play a key role in the regulation of inflammatory factors and the activation of immune cells,and that a variety of proinflammatory cytokines initiate their immune response through the Janus kinase(JAK)signal transduction pathway.A variety of smallmolecule oral drugs that inhibit Janus kinase activity have emerged.Randomized controlled trials in patients with RA using Janus kinase inhibitors such as Tofacitinib for treatment have also proven the effectiveness and safety of these drugs.At present,the treatment of RA is mainly the control of inflammation,and there is no good treatment for the cartilage damage of the affected joints.In recent years,a small molecule organic compound Kartogenin(KGN)has been discovered that has a strong ability to promote the differentiation of bone marrow mesenchymal stem cells(BMSCs)into cartilage.A lot of research has been done on its application in regenerative medicine.The results confirm that KGN can protect and regenerate cartilage with mechanical damage.At the same time,it can also recruit adult stem cells of autologous origin,and repair damaged cartilage without relying on exogenous cell implantation.These advantages make us very interested in the application of KGN in the protection of articular cartilage in RA and the repair of damaged cartilage.With the continuous deepening of research on nano-drugs,the advantages of enhancing the delivery of insoluble drugs,prolonging the plasma retention time of drugs,reducing the dosage of drugs,and toxic and side effects have been continuously discovered.These advantages of nanomedicine can be used to make up for the current systemic medications and large-dose administration of RA treatment,which bring high costs and large toxic and side effects.The purpose of this study was to explore the creation of a polyamino acid nano-drug-loading system with a double core-shell structure in order to achieve JAK inhibitors that inhibit the inflammatory state and KGN that promotes cartilage protection and repair.The two drugs can be controlled in time and space.In order to repair the damaged cartilage based on the traditional antiinflammatory treatment of RA.Exploring the problem of RA damaged cartilage repair which currently has no treatment method,also provides new ideas for comprehensive treatment of RA.Material method: First maleimide-polyethylene glycol(MalPEG5000)and glutamate NCA,KPLGLAG-FFF,maleimide and lysine NCA,cystine NCA,through ring-opening polymerization Shells and cores of different degrees of polymerization of nanocarriers are synthesized by chemical reactions such as,deprotection and condensation.A shell with a suitable polymerization degree and a suitable shell core assembly ratio were screened to form a stable nanometer drug-loading system with a suitable particle size.Then the JAK inhibitor Tofacitinib and KGN,which are currently used clinically,are encapsulated in a nanocarrier to form a complete nano-drug loading system.Subsequently,the therapeutic effect of the nano-drug system was initially verified in a CIA mouse model.Five experimental groups were designed,namely the vector / Tofacitinib / KGN group,the vector / Tofacitinib group,the vector / KGN group,the Tofacitinib / KGN group and the Control group.The inflammatory status of the affected joints of the mice was evaluated during treatment.After the treatment,the external images of the affected joints of the mice were collected,and the hind limbs of the mice were reconstructed by Micro-CT scan.Results: The particle size of the complete nano drug-loading system was 100 nm,the drug loading rate of tofacitib was 14.2 wt%,and the drug loading rate of KGN was 2.4 wt%.Carrier / Tofacitinib / KGN and Carrier / Tofacitinib can effectively inhibit the swelling of affected joints and hind paws of CIA mice.At the same time,the carrier / Tofacitinib / KGN can also protect the smoothness of the affected articular surface.Conclusion: In this study,we successfully constructed a polyamino acid nanoparticle with double core-shell structure with enzymatic digestion responsiveness,and tested its particle size and ability to load drugs.The feasibility of this as a carrier for RA treatment was initially verified.At the same time,animal experiments have shown that the carrier / Tofacitinib / KGN can alleviate the progress of RA and protect the affected joints.Proved the advantages of nano-medicine in reducing the dosage,reducing toxic and side effects,and reducing the burden on patients.It provides new ideas for comprehensive treatment of RA.