携载microRNA-140外泌体/海藻酸钠/胶原水凝胶修复关节软骨损伤

Articular cartilage injury repaired with microRNA-140 exosomes/sodium alginate/collagen hydrogel

背景:研究已证实,上调microRNA-140表达可部分抑制膝关节软骨组织与细胞的骨关节炎样改变,延缓骨关节炎进程,提示microRNA-140参与了骨关节炎的发病机制。目的:采用海藻酸钠/胶原水凝胶负载过表达microRNA-140的外泌体,进一步分析microRNA-140参与骨关节炎的相关机制。方法:利用慢病毒感染大鼠骨髓间充质干细胞使其过表达microRNA-140,随后分离提取外泌体,得到过表达microRNA-140的外泌体。制备负载外泌体的海藻酸钠/胶原水凝胶。采用随机数字表法将32只SD大鼠随机分为4组,每组8只:正常对照组不进行任何处理,骨关节炎组、未转染外泌体组、转染外泌体组均通过膝关节腔内注射碘乙酸钠的方式建立骨关节炎模型,造模2周后,骨关节炎组膝关节腔内注射PBS,未转染外泌体组、转染外泌体组膝关节腔内分别注射负载未过表达microRNA-140与过表达microRNA-140外泌体的海藻酸钠/胶原水凝胶。造模后第6周,检测大鼠机械刺激缩足反应阈值、滑膜液炎症因子浓度、软骨相关基因表达、膝关节软骨组织的组织学变化与焦亡相关蛋白表达。结果与结论:①与正常对照组比较,骨关节炎组机械刺激缩足反应阈值、Ⅱ型胶原及SOX9 mRNA表达、Ⅱ型胶原免疫荧光强度均减少(P<0.05),滑膜液中促炎症因子水平增加(P<0.05),基质金属蛋白酶13、血小板反应蛋白解整合素金属肽酶5(ADAMTS5)mRNA表达增加(P<0.05),NLRP3、ASC、GSDMD p30、caspase-1 p20、白细胞介素1β、白细胞介素18蛋白表达均增加(P<0.05),GSDMD、cleaved caspase-1免疫荧光强度增强(P<0.05),软骨组织损伤严重。②与骨关节炎组比较,两外泌体组机械刺激缩足反应阈值、Ⅱ型胶原及SOX9 mRNA表达、Ⅱ型胶原免疫荧光强度均增加(P<0.05),滑膜液中促炎症因子水平减少(P<0.05),基质金属蛋白酶13 mRNA表达减少(P<0.05),NLRP3、ASC、GSDMD p30、caspase-1 p20、白细胞介素1β、白细胞介素18的蛋白表达均减少(P<0.05),GSDMD、cleaved caspase-1的免疫荧光强度减弱(P<0.05),软骨组织损伤减轻(P<0.05),并且转染外泌体组的作用更强。③结果表明,microRNA-140可通过抑制炎症、维持软骨稳态、抑制软骨焦亡来减轻骨关节炎大鼠的疼痛反应,降低软骨损伤,发挥骨关节炎治疗作用。

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.