甲基丙烯化明胶微球缓释Kartogenin修复髓核退变的体外评估

In vitro evaluation of sustained release Kartogenin by gelatin methacryloyl microspheres for repairing nucleus pulposus degeneration

背景:细胞外基质合成与降解的失衡是髓核退变的主要原因,小分子药物Kartogenin(KGN)可恢复基质合成和降解的平衡。利用合适的载药系统实现KGN的缓释对KGN发挥长期有效的治疗至关重要。目的:用甲基丙烯酰化明胶(gelatin methacryloyl,GelMA)包裹KGN,通过微流控技术制备成可注射的水凝胶微球,探究其生物相容性和对髓核细胞生物学功能的影响。方法:将β-环糊精(β-cyclodextrins,β-CD)与KGN混合成包合物,与10%GelMA按1∶9的体积混合,利用微流控技术制备可注射水凝胶微球GelMA@β-CD@KGN,扫描电镜表征微球的微观形貌,检测水凝胶微球浸泡于PBS中1个月的药物释放情况。提取SD大鼠髓核细胞,将第1代细胞分3组培养:对照组单独培养髓核细胞,另外两组分别将GelMA@β-CD微球、GelMA@β-CD@KGN微球与髓核细胞共培养,利用CCK-8法检测细胞增殖,活死细胞染色检测细胞存活。分别用含有白细胞介素1β和不含白细胞介素1β的完全培养基将髓核细胞与两种微球共培养,采用RT-PCR法检测髓核细胞基质合成蛋白和分解蛋白的mRNA表达。结果与结论:①扫描电镜下可见,冻干后的GelMA@β-CD@KGN微球为规则的球形,保持高度分散且大小均一,形状饱满;GelMA@β-CD@KGN微球体外可持续释放药物,至30 d时药物释放量达到总量的62%;②活死细胞染色显示,GelMA@β-CD@KGN可保持髓核细胞的活性;CCK-8检测显示,GelMA@β-CD@KGN可促进髓核细胞的增殖;③在含或不含白细胞介素1β的完全培养基中,GelMA@β-CD@KGN微球组聚集蛋白聚糖、Ⅱ型胶原的mRNA表达均高于GelMA@β-CD微球组(P<0.05,P<0.01),基质金属蛋白酶13、血小板反应蛋白解整合素金属肽酶5的mRNA表达均低于GelMA@β-CD微球组(P<0.01);④结果表明,GelMA@β-CD@KGN微球具有良好的生物相容性和药物缓释能力,作为载药系统是一种具有广阔应用前景的生物材料。

BACKGROUND:The imbalance of matrix synthesis and degradation is the main cause of nucleus pulposus degeneration.Small molecule drug Kartogenin(KGN)can restore the balance of matrix synthesis and degradation.Sustained release of KGN using an appropriate drug delivery system is essential for the long-term and effective treatment of KGN.OBJECTIVE:To prepare the injectable hydrogel microspheres by encapsulating KGN with gelatin methacryloyl(GelMA)by microfluidic technology and to investigate the biocompatibility and biological function of nucleus pulposus cells.METHODS:β-Cyclodextrins(β-CD)and KGN were mixed firstly and then mixed with 10%GelMA at a volume of 1:9.Injectable hydrogel microspheres GelMA@β-CD@KGN were prepared by microfluidic technology.The micromorphology of the microspheres was characterized using a scanning electron microscope.The drug release of hydrogel microspheres immersed in PBS within one month was measured.Nucleus pulposus cells were isolated from SD rats and passage 1 cells were cultured in three groups.In the control group,nucleus pulposus cells were cultured separately.In the other two groups,GelMA@β-CD microspheres and GelMA@β-CD@KGN microspheres were co-cultured with nucleus pulposus cells.Cell proliferation was detected by CCK-8 assay and cell survival was detected by live/dead cell staining.Cells were cultured by two complete media with and without interleukin-1βwith two kinds of microspheres.mRNA expressions of matrix synthesis and decomposing proteins in nucleus pulposus cells were detected by RT-PCR.RESULTS AND CONCLUSION:(1)Under the scanning electron microscope,the GelMA@β-CD@KGN microspheres after lyophilization were regularly spherical,highly dispersed,uniform in size and full in shape.GelMA@β-CD@KGN microspheres sustained drug release in vitro,reaching 62%of the total drug release at 30 days.(2)Live/dead cell staining showed that GelMA@β-CD@KGN could maintain the activity of nucleus pulposus cells.CCK-8 assay showed that GelMA@β-CD@KGN could promote the proliferation of nucleus pulposus cells.(3)In the complete media with and without interleukin-1β,mRNA expression of aggrecan and type II collagen was higher in the GelMA@β-CD@KGN microsphere group than that in the GelMA@β-CD microsphere group(P<0.05,P<0.01);mRNA expression of matrix metalloproteinase 13 and platelet reactive protein disintegrin metallopeptidase 5 was lower than that in the GelMA@β-CD microsphere group(P<0.01).(4)These findings indicate that GelMA@β-CD@KGN microspheres have good biocompatibility and sustained drug release ability.As a drug delivery system,it is a kind of biomaterial with broad application prospects.