The Research Of Chondrogenic Effect Of Hyaluronic Acid/RGD-Functionalized Pectin Hydrogel

Objective:Without blood vessels and nerves,articular cartilage has limited self-repair ability.The traditional method of treating articular cartilage defects also has the nect of the bottle.The cartilage tissue is composed of chondrocytes and extracellular matrix,including hyaluronic acid.So we investigate the chondrogenic effect of our injectable hydrogel system based on hydrazide reaction hyaluronic acid-adipic dihydrazide(HA-ADH)/G4RGDS-aldehyde pectin(PAD-RGD)in vitro and in vivo.Methods: 1.Preparation of materials: hydrazide-based hyaluronic acid-functionalized oxidative pectin hydrogel was prepared by hydrazone cross-linking method.The prepared materials were analyzed,including morphology,mechanical strength,gel time and degradation time of different hydrogels with different weight ratios of the two substances after crosslinking,and the physical and chemical properties of the hydrogels were comprehensively evaluated.2.In vitro experiments: Cells were encapsulated in hydrogel for viable cell staining,Western-blot,qPCR,GAGs assays and type II collagen immunofluorescence staining to verify hydrogel-promoted cells proliferation and other experiments of the chondrogenisis effect evaluation,a comprehensive assessment of hydrogel in vitro biological characteristics.3.In vivo experiments: New Zealand rabbit models of intercondylar cartilage defect(n = 6)were made,and HA-ADH / PAD-RGD injectable hydrogels with different weights(8/2,6/4)were injected into the defect site.Three months later,the cartilage specimens were fixed,decalcified,embedded in paraffin,sectioned and stained to evaluate the effect of cartilage repair in vivo.Results: 1.Material preparation and characterization.Studies have shown that the hydrogel has the ideal spatial structure,adjustable gel time,mechanical strength and degradation time.Hydrogels of different weight ratios have different physicochemical properties.Moreover,our study found that among the three weight ratios,hydrogels of 6/4 weight ratio have the best physicochemical properties.2.In vitro experiments show that the hydrogel has good cell compatibility and histocompatibility,and in the meantime it can promote the proliferation of chondrocytes and promote the differentiation of chondrocytes as well as maintain the phenotype of chondrocytes.Among them,the cells in the hydrogel with the weight ratio of 6/4 has the strongest viability,the strongest proliferative ability and the highest expression of type II collagen gene and protein.3.In vivo test results showed that HA-ADH / PAD-RGD injectable hydrogels can promote chondrocytes proliferation and extracellular matrix secretion,maintain chondrocyte phenotype and promote cartilage regeneration and repair.Among them,the weight ratio of 6/4 hydrogel cartilage has the best result of reparing.The repair result is significantly better than the control group and the weight ratio of 8/2 group.Conclusion:Hydrogels with different weight ratios of HA-ADH / PAD-RGD can promote chondrocyte proliferation,extracellular matrix secretion,maintain chondrocyte phenotype and promote cartilage regeneration,with the weight ratio of 6/4 being the best ratio to maintain the cartilage phenotype.In conclusion,injectable hydrogel which is based on hyaluronic acid-adipic dihydrazide(HA-ADH)/ G4RGDS-aldehyde pectin(PAD-RGD)have the ability to be a prosepective scaffold for cartilage tissue engineering.