[Proliferation and chondrogenic differentiation of precartilaginous stem cells in self-assembling peptide nanofiber scaffolds].

OBJECTIVE: To construct a new type of self-assembling peptide nanofiber scaffolds-RGDmx, and to study the cell compatibility of the new scaffolds and the proliferation and chondrogenic differentiation of precartilaginous stem cells (PSCs) in scaffolds.

METHODS: PSCs were separated and purified from newborn Sprague Dawley rats by magnetic activated cell sorting and indentified by immunohistochemistry and immunofluorescent staining. The RGDmx were constructed by mixing KLD-12 and KLD-12-PRG at volume ratio of 1:1. PSCs at passage 3 were seeded into the KLD-12 scaffold (control group) and RGDmx scaffold (experimental group). The proliferation of PSCs in 2 groups were observed with the method of cell counting kit (CCK)-8 after 1, 3, 7, and 14 days after culture. The RGDmx were constructed by mixing KLD-12-PRG and KLD-12 at different volume ratios of 0, 20%, 40%, 60%, 80%, and 100% and the proliferation of PSCs was also observed. The complete chondrogenic medium (CCM) was used to induce chondrogenic differentiation of PSCs in different scaffolds. The differentiation of PSCs was observed by toluidine blue staining and RT-PCR assay.

RESULTS: PSCs were separated and purified successfully, which were identified by immunohistochemistry and immunofluorescent staining methods. The results of CCK-8 showed that the absorbance (A) value in the experimental group increased gradually and reached the highest at 7 days; the A value in the experimental group was significantly higher than that in the control group at 7 days and 14 days (P < 0.05). Meanwhile, the A value in the RGDmx scaffold with a volume ratio of 40% was significantly higher than those in others (P < 0.05). After 14 days of induction culture with CCM, the toluidine blue staining results were positive in 2 groups; the results of RT-PCR showed that the expression levels of collagen type II and the aggrecan in the experimental group were significantly higher than those in the control group (P < 0.05).

CONCLUSION: The self-assembling peptide nanofiber scaffold-RGDmx is an ideal scaffold for tissue engineer because it has good cell compatibility and more effective properties of promoting the differentiation of PSCs to chondrocytes.