Mechanical performance and biocompatibility study of methacrylated Gellan gum hydrogels with potential for nucleus pulposus regeneration

摘要

Methacrylated gellan gum hydrogels, obtained either by ionic- (iGGMA)and photo-crosslinking (phGG-MA), have been investigated aspotential biomaterials for supporting nucleus pulposus (NP) regenerationand/or repair [1,2]. In previous work, some advantages wereattributed to GG-MA hydrogels, such as: (i) the possibility to controlendothelial cells infiltration and blood vessel ingrowth’s, (ii) tunableand improved mechanical properties, and (iii) in situ gelation, withinseconds to few minutes. In this study, the mechanical and biologicalperformance of these hydrogels was firstly evaluated in vitro. Humanintervertebral disc (hIVD) cells obtained from herniated patients werecultured within both hydrogels, for 1 up to 21 days. Dynamic mechanicalanalysis and biological characterization (calcein-AM staining, ATPand DNA quantification and PCR) were performed after specific timesof culturing. A biocompatibility study was also performed in vivo, bysubcutaneous implantation of acellular iGG-MA and phGG-MA hydrogelsin Lewis rats for the period of 10 and 18 days. Tissue response tothe hydrogels implantation was determined by histological analysis(haematoxylin-eosin staining). The in vitro study showed that both cellloading and culturing time do not have an effect on the mechanicalproperties of the hydrogels. Regarding their biological performance,the iGG-MA and phGG-MA hydrogels showed to be effective on supportinghIVD cells encapsulation and viability up to 21 days of culturing.Human IVD cells were homogeneously distributed within thehydrogels and maintained its round-shape morphology during culturingtime. The in vivo biocompatibility study showed that iGG-MA andphGG-MA hydrogels do not elicit any deleterious effect, as denoted bythe absence of necrosis and calcification, or acute inflammatory reaction.A thin fibrous capsule was observed around the implanted hydrogels.The results presented in this study indicate that the iGG-MA andphGG-MA hydrogels are stable in vitro and in vivo, support hIVD cellsencapsulation and viability, and were found to be well-tolerated andnon-cytotoxic in vivo, thus being potential candidates for NP regeneration.