Biocompatibility and Toxicity of Cell-Derived Extracelluar Matrix and Silk Fibroin Scaffold in vitro and in traumatic brain injury rat model

초록

Objective : Recently, cell-based approaches using neural stem/progenitor of mesenchymal stem cells in combination with biomaterials for brain tissue engineering have been actively developed. In this study, we investigated the biocompatibility and toxicity of two biomaterials, chondrocyte derived ECM (ECM) scaffold and silk fibroin (SF) scaffold in vitro and in vivo for their use in brain tissue engineering Materials & Methods : MSCx were isolated from the bone marrow of 100g adult male SD rats. The wst-1 assay, cell attachment and H&E stain were carried out to assess the biocompatibility of the two scaffolds in vitro. For in vivo test, the 6-mm diameter craniotomy was performed at bregma, and then a cortical tissue was removed mechanically by 6-mm biopsy-punch. ECM and SF were transplanted into the lesion cavity of the injured brain, and the rats were sacrificed 7, 21, and 42 days after TBI. Thirty-six male SD rats were randomly divided into four groups with 9 rats per group (i.e. Sham, TBI, TBI+ECM, TBI+SF) for behavioral test. Motor function was measured using rota-rod test and Modified Neurological Severity Scores(mNSS), and all the time points of the brain tissue was processed for histopathological analysis. Results : The ECM scaffold had much higher cell viability and attachment to MSCs, compared with SF scaffold in vitro. ECM and SF scaffolds implanted into the lesion area of the cortex still existed in the site after being grafted for 6 weeks. For the lesion volume, SF group was significantly larger than all other groups at 6 weeks. There were no significant differences in the rota-rod test and mNsscores between control, ECM and SF groups. With immunohistochemistry after 1, 3 and 6 weeks of implantation, GFAP-positive astrocytes could be seen around the grafts in the three groups. In the groups of ECM and SF, there was little immunostaining in the tissue, compared to the control tissue. However there were no significant differenced in statistical anal