Preparation Of Gold/Polydopamine Nanocomposite Loaded With Tocilizumab And Its Therapeutic Effect On Rheumatoid Arthritis

Objective: To solve the problems of rheumatoid arthritis drugs with high cost and strong side effects,Au-polydopamine nanocomposites loaded with TCZ drug were prepared based on drug-loading nano-technology.The ability of Au@PDANPs/TCZ to scavenge reactive oxygen species and biocompatibility were evaluated as well.Finally,to explore the feasibility of Au@PDANPs/TCZ in clinical treatment and provide some research experience for the treatment of RA disease,the therapeutic effect of this complex on Wistar rat model of CIA were studied.Methods: The PDANPs were modified with Au NPs to form Au@PDANPs,and then TCZ was loaded onto the composite through Schiff base reaction and the electrostatic integration.The morphology and structure of Au@PDANPs/TCZ complex were characterized by TEM,FT-IR and UV-Vis method.Pyrogallol autoxidation method was used to characterize the scavenging ability to oxygen free radicals,and the toxicity of the composite to goat temporomandibular joint chondrocytes was measured by MTT and AO/EB methods.Animal models of RA were constructed in the hind paw area of Wistar rats using collagen II.The animals were divided into RA group,Au @ PDANPs/TCZ treatment group,Au@PDANPs treatment group,PDANPs treatment group,TCZ treatment group,and physiological saline treatment group.For each group,ankle joint injection of corresponding drug was administered once a week after modeling until weeks later when the final treatment results were tested.CT was used for imaging tests,and ELASA kits were used for serological tests of tumor necrosis factor-α,interleukin-1 and vascular endothelial growth factor.Finally,specimens were collected and sectioned for pathological examination.Results:(1)Characterization of Au@PDANPs/TCZ composite: TEM showed that the diameter of the obtained PDANPs was about 154.8 ± 31.9 nm,which had good dispersibility and uniform particle size.Au NPs were randomly distributed on the surface of PDANPs with a diameter of about 11.4 ± 2.9 nm.XRD results confirmed that the introduction of Au.FT-IR results demonstrated that TCZ chemically cross-linked with PDANPs through Schiff base reaction,and UV-Vis results demonstrated that TCZ bound to Au through electrostatic adsorption.(2)Antioxidant evaluation of Au@PDANPs/TCZ composite: The result of pyrogallol autoxidation method showed that Au@PDANPs/TCZ had excellent ability to scavenge oxygen free radicals.(3)Evaluation of cytocompatibility of Au@PDANPs/TCZ composite: MTT and AO/EB staining results showed that Au@PDANPs/TCZ had low cytotoxicity to goat temporomandibular joint chondrocytes.(4)Evaluation of Au@PDANPs/TCZ composite in vivo: Two weeks after CIA model rats were treated with ankle joint injection using corresponding drug,Au@PDANPs/TCZ significantly reduced the joint swelling rate in rats,and inhibited the expression levels of TNF-α,IL-1 and VEGF in serum.Imaging and pathological tests proved that Au@PDANPs/TCZ had a good therapeutic effect on arthritis in CIA rats.Conclusions: In conclusion,Au@PDANPs/TCZ complex is a good functional drug carrier,which can be firmly combined with the macromolecular drug TCZ through Schiff base reaction and electrostatic effect,as well as exercise the function of scavenging oxygen free radicals.Au@PDANPs/TCZ complex has good biocompatibility.In the CIA animal model,Au@PDANPs/TCZ scavenged oxygen free radicals and at the same time had a synergistic effect on the therapeutic effect of RA,producing a better therapeutic effect than using TCZ alone.