Articular cartilage injury repaired with microRNA-140 exosomes/sodium alginate/collagen hydrogel
BACKGROUND:Studies have confirmed that up-regulation of microRNA-140 expression can partially inhibit osteoarthritis-like changes in knee cartilage tissues and cells and delay the progression of osteoarthritis,suggesting that microRNA-140 is involved in the pathogenesis of osteoarthritis.OBJECTIVE:To further analyze the mechanism of microRNA-140 involvement in osteoarthritis by loading exosomes overexpressing microRNA-140 with sodium alginate/collagen hydrogel.METHODS:Lentivirus was used to infect rat bone marrow mesenchymal stem cells to overexpress microRNA-140,then exosomes were isolated and exosomes overexpressing microRNA-140 were obtained.Sodium alginate/collagen hydrogels loaded with exosomes were prepared.Thirty-two SD rats were randomly divided into four groups,with 8 rats in each group.Normal control group did not receive any treatment.The osteoarthritis model was established by injecting sodium iodoacetate into the knee cavity in the osteoarthritis group,the non-transfected exosome group and the transfected exosome group.Two weeks later,PBS was injected into the knee cavity in the osteoarthritis group.Sodium alginate/collagen hydrogel carrying non-overexpressing microRNA-140 and overexpressing microRNA-140 exosomes were injected into the knee cavity of the non-transfected exosome group and transfected exosome group.At 6 weeks after modeling,the threshold of mechanical foot withdrawal response,the concentration of inflammatory factors in synovial fluid,the expression of chondrogen-related genes,the histological changes of knee cartilage and the expression of pyroptosis related proteins were detected in rats.RESULTS AND CONCLUSION:(1)Compared with normal control group,the threshold value of mechanical stimulation foot contraction response,type Ⅱ collagen,SOX9 mRNA expression levels,and Type Ⅱ collagen immunofluorescence intensity were decreased in the osteoarthritis group(P<0.05),and proinflammatory cytokine levels were increased in synovial fluid(P<0.05).The mRNA expressions of matrix metalloproteinase 13 and a disintegrin and metalloproteinase with thrombospondin motifs-5(ADAMTS-5)were increased(P<0.05),and the protein expression levels of NLRP3,ASC,GSDMD p30,caspase-1 p20,interleukin-1β,and interleukin-18 were increased(P<0.05).Immunofluorescence intensity of GSDMD and cleaved caspase-1 was increased(P<0.05),and cartilage tissue was severely damaged.(2)Compared with osteoarthritis group,the threshold value of mechanical stimulation foot contraction response,type Ⅱ collagen,SOX9 mRNA expression levels,and type Ⅱ collagen immunofluorescence intensity in the non-transfected and transfected exosome groups were increased(P<0.05);proinflammatory cytokine levels were decreased in synovial fluid(P<0.05).The mRNA expression of matrix metalloproteinase 13 was decreased(P<0.05),and the protein expression levels of NLRP3,ASC,GSDMD p30,caspase-1 p20,interleukin-1β,and interleukin-18 were decreased(P<0.05).The immunofluorescence intensity of GSDMD and cleaved caspase-1 decreased(P<0.05),and the cartilage tissue damage was reduced(P<0.05),and the effect was stronger in the transfected exosome group.(3)These results conclude that microRNA-140 can reduce the pain response of rats with osteoarthritis by inhibiting inflammation,maintaining cartilage homeostasis,and inhibiting cartilaginous pyroptosis,thereby reducing cartilage damage and playing a therapeutic role in osteoarthritis.