Study On The Effect Of PH-responsive Metal-organic Framework Nano Drug-loading System In The Treatment Of Osteoarthritis

OBJECTIVE: Osteoarthritis(OA)is a chronic joint degenerative disease.Usually,OA patients have an acidic environment in the joint cavity.Intra-articular injection is currently an effective method for treating OA,but the drug is easily cleared in the joint cavity.In this project,a p H-responsive metal-organic framework nano drug-loading system was designed.The metal-organic framework(MOF)was modified with hyaluronic acid(HA)and loaded with antiinflammatory drug protocatechuic acid(PCA)for OA Treatment.METHODS: The experiment is divided into three parts.Part 1:MOF@HA@PCA nano drug delivery system construction and physical and chemical properties detection.First,MOF was synthesized by hydrothermal synthesis,then MOF was modified with HA,and finally PCA was loaded to form MOF@HA@PCA nano drug-loading system.Characterization of materials:Fourier transform infrared spectroscopy(FT-IR)is used to characterize the chemical structure of nanoparticles.X-ray diffraction(XRD)is used to characterize the crystal structure of nanoparticles.Transmission electron microscopy(TEM)is used to characterize nanometers the size and morphology of the particles.Dynamic light scattering analyzer(DLS)is used to characterize the particle size and zeta potential of the nanoparticles.And detect the response performance and drug release performance of the nano-drug loading system in vitro.Part 2: The anti-inflammatory effect of MOF@HA@PCA nano drug delivery system on interleukin-1β-induced chondrocytes.The experiment is divided into four groups: control group,IL-1β group,PCA group,MOF@HA@PCA group.The cytotoxicity of MOF@HA and MOF@HA@PCA was detected by the MTT method.And the in vitro resistance of the MOF@HA@PCA nano drug delivery system was evaluated by q RT-PCR,Calcein-AM / PI staining,Safranin O staining,and immunofluorescence staining inflammatory effect.Part III: The therapeutic effect of MOF@HA@PCA nano drug-loading system on osteoarthritis in rats.In order to explore the role of the nano drug-carrying system in animals,the rat osteoarthritis model was constructed by ACLT.The gross observation and gross scoring,hematoxylineosin(HE)staining,safranine-fast green staining,immunohistochemical staining,histological score was used to observe the severity of OA in SD rats at 4th and 8th weeks to evaluate the effect of the MOF@HA@PCA nano drug delivery system in vivo.RESULT: FT-IR results showed that MOF products were formed,HA has been successfully coupled with MOF nanoparticles.XRD results show that HA coupling will not change the crystal structure of MOF nanoparticles.TEM images show the dispersion of nanoparticles after HA modification Better.DLS size measurement shows that the average size of MOF@HA@PCA is 123.4 nm.The in vitro release experiment results show that at p H 7.4,MOF@HA@PCA releases only about 14.8% of PCA within 24 hours,while at p H 5.6,about 23.4% of PCA was released,and the drug release rate was significantly accelerated,showing obvious p H responsiveness.MTT results show that MOF@HA is biocompatible,MOF@HA@PCA shows the highest cell viability at a concentration of 30 μg /Ml.Calcein-AM / PI staining results show that MOF@HA@PCA can promote chondrocyte proliferation.The q RT-PCR and safranin O staining results showed that MOF@HA@PCA had cartilage protection.And q RT-PCR and immunofluorescence staining results showed that MOF@HA@PCA had antiinflammatory effects.Gross observation and gross scoring,HE staining,safranine-fast green staining,and histological scoring results show that MOF@HA@PCA has cartilage protection and cartilage repair effect is better.The immunohistochemical staining shows that MOF@HA@PCA has antiinflammatory effect.CONCLUSION: This study successfully constructed a p H-responsive nano drugloading system MOF@HA@PCA functionalized with hyaluronic acid,which can achieve the delivery and sustained release of local anti-inflammatory drugs and prolong the residence time of the drugs in the joint cavity.The system respond to the acidic environment of joint inflammation and improve the treatment efficiency.The system have anti-inflammatory and cartilage protection in vivo and in vitro,and provide a new way for the future clinical treatment of OA.