The Effect Of LncRNA Malat-1 From Mesenchymal Stem Cell-Derived Exosomes On Chondrocyte Repair In Osteoarthritis

Background and Objective:The main pathology of osteoarthritis(OA)is degeneration of articular chondrocytes,increased inflammation and degradation of extracellular matrix.The increase of matrix metalloproteinase(MMPs)promotes the degradation of extracellular matrix proteins.Exosomes derived from human bone marrow mesenchymal stem cells have the potential to reduce cartilage damage and inflammation.Lnc RNA malat-1 can reduce articular chondrocyte inflammation and extracellular matrix degradation,and play an important role in protecting chondrocytes.We speculate that the exosomes from h MSCs overexpressing lnc RNA malat-1 play an important role in chondrocytes.The purpose of this study was to explore the effect of exosomes from h MSCs overexpressing lnc RNA malat-1 on chondrocytes.The effects of inflammation and extracellular matrix further elucidate the role of exosomes from bone marrow mesenchymal stem cells overexpressing lnc RNA malat-1 in chondrocyte degeneration.Method:(1)The exosomes of human bone marrow mesenchymal stem cells were isolated by the isolation kit,and the exosomes were identified by transmission electron microscopy,particle size analysis experiments and Western Blot.(2)The osteoarthritis model of Sprague-Dawley(SD)rat and IL-1β-induced OA chondrocyte model were established using type II collagenase.(3)A stable transgenic strain overexpressing lnc RNA malat-1 was constructed by lentivirus acting on human bone marrow mesenchymal stem cells,and exosomes were extracted for q RT-PCR detection.(4)Changes in chondrocyte viability,proliferation,inflammation,degradation of extracellular matrix proteins and cell migration ability were detected by CCK-8detection,Edu staining,ELISA experiment,Western Blot and transwell experiment.Chondrocyte apoptosis was assessed by flow cytometry,Hoechst 33342/PI staining and Western blotting.(5)Safranin O-fast green(SO)staining and HE staining were used to evaluate the morphological and pathological changes of SD rat knee cartilage.Result:(1)The appearance of exosomes is a round cup-shaped structure,the main peak of particle size is about 144 nm,and the expression of exosome surface molecular markers CD63,CD81,and TSG101 is positive,indicating that the separation of exosomes was successful.(2)After the establishment of the SD rat osteoarthritis model of SD rat,it was observed that the cartilage surface was rough,the shape was irregular,the fibers were broken,and the cartilage was significantly damaged.After exosome treatment,the cartilage damage was significantly declined.After chondrocytes were induced by IL-1β,the inflammatory factor IL-6 was significantly increased,and after co-culture with exosomes,the inflammatory factor IL-6 decreased.(3)After the two kinds of exosome were detected by q RT-PCR,the expression level of lnc RNA malat-1 in h MSCsmalat-1-Exos was 4.03 times higher than that in h MSCs-Exos.(4)The protein expressions of IL-6,MMP-13 and capase-3 in the IL-1β group were significantly increased,the apoptosis rate was also increased,and the cell proliferation ability,viability and migration ability were decreased.In the h MSCs-Exos group,the negative effects induced by IL-1β were greatly declined,while a more substantial decrease in IL-6,MMP-13 and capase-3 protein levels was observed in the h MSCsmalat-1-EVs group,apoptosis decreased,and cell proliferation,viability and migration were improved.(5)The articular cartilage was significantly damaged in the OA group,and the scores of OARSI and Mankin were significantly increased.The articular cartilage structure in the h MSCs-Exos group was clearer,and the scores of OARSI and Mankin were decreased.In the h MSCsmalat-1-Exos group,the structure of rat articular cartilage was clearer than the h MSCs-Exos group,the surface was smooth,and the scores of OARSI and Mankin were significantly decreased.Conclusion:In OA,the exosomes of lnc RNA malat-1-overexpressing human bone marrow mesenchymal stem cell can promote chondrocyte proliferation and migration,inhibit inflammation and extracellular matrix degradation,and delay chondrocyte degeneration,with good results.protective effect.