In vitro evaluation of sustained release Kartogenin by gelatin methacryloyl microspheres for repairing nucleus pulposus degeneration / 中国组织工程研究

ABSTRACT

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-1β with 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.