Targeting Therapy For Spinal Cord Injury Mediated By Nanoparticles Made Of Albumi

Objective:Methylprednisolone(MP)was encapsulated into the human serum albumin nanoparticles(HSA),and the surface of HSA was modified with polypeptide NEP1-40 to prepare a new targeting drug delivery system of NEP1-40-MP-NPs.The drug delivery system can overcome poor solubility of MP,extend the drug half-life,enhance the targeting of drug,reduce side effects and improve patient compliance.We further investigated the toxic effects of NEP1-40-MP-NPs on rat Schwann cell RSC-96 and investigated whether NEP1-40-MP-NPs can improve the therapeutic effect after spinal cord injury.Methods:In this study,PEG-MP complex was prepared by PEG400 and MP.MP was loaded into blank NPs by PEG-MP to achieve MP-NPs.Then,NEP1-40 was conjugated to the surface of nanoparticles by bifunctional crosslinker NHS-PEG5000-MAL,and the NEP1-40-MP-NPs was prepared.Secondly,We investigated the morphology,encapsulation efficiency and particle size of MP-NPs.NEP1-40-MP-NPs was identified by fluorescence detection,HPLC and IR scanning,and the drug release behavior of NEP1-40-MP-NPs was investigated in the PBS of pH 7.4.Subsequently,observation of cell morphology,MTT test and hemolysis test were used to investigate the in vitro toxicity of NEP1-40-MP-NPs.Confocal laser scanning was used to study the uptake and localization of NEP1-40-MP-NPs in vitro.Finally,we constructed the model of spinal cord injury to evaluate the pharmacodynamics of NEP1-40-MP-NPs in SD rats.Results:the results showed that MP-NPs was spherical,their particle sizes were accorded with normal distribution and their encapsulation efficiency was 84.06 ± 3.48%.These data confirmed that cumulative release of NEP1-40-MP-NPs was 59.047 ± 4.084%in the 96 hours,which showed good sustained release and long-term effect.Under the same dosing time and concentration,the cytotoxicity of MP-NPs and NEP1-40-MP-NPs to RSC-96 cells was significantly reduced,and their hemolysis rate is less than 5%.The red and green fluorescence intensity of NEP1-40-MP-NP in RSC-96 cells was much stronger than that of HUVEC cells,and there was a significant difference(P<0.05).In vivo pharmacodynamic experiments showed that NEP1-40-MP-NP reduced the attack of free radicals on the body,increased the degree of inflammation,enhanced the function of endogenous oxygen free radical scavenging system,reduced the loss of bone density,accelerated the repair process after injury,and increased the BBB scores.Conclusion:The targeted drug delivery system NEP1-40-MP-NPs has been successfully constructed in this study,which specifically targeted to Nogo protein-expressing RSC-96 cells in vitro,and treatment of spinal cord injury has a good effect in vivo.