P38/akt pathway regulates the oriented differentiation of bone marrow mesenchymal stem cells in nanofiber annulus fibrosus scaffolds with different spatial structures / 中国组织工程研究

ABSTRACT

BACKGROUND: Previous studies have shown that a variety of materials can be used for the construction of tissue engineering scaffolds. The topological structure of the scaffold surface has a regulatory effect on the biological behaviors such as stem cell proliferation and differentiation, but the specific mechanism is still unclear. OBJECTIVE: To investigate the role of P38 and Akt pathways in the oriented differentiation of bone marrow mesenchymal stem cells in nanofiber scaffolds. METHODS: Three kinds of nanofiber scaffolds (AFS, AYS, 3-DPS) with different structures were constructed. Rat bone marrow mesenchymal stem cells were inoculated on the surface of three kinds of nanofiber scaffolds. After osteogenic induction, cell morphology, adhesion and proliferation were detected. mRNA expression levels of key phenotype molecules (COLIα1, COLIIα1, Aggrecan, Sox-9) were measured using qRT-PCR. Intracellular P38, AKT, ERK1/2 and JNK expression was detected by western blot assay. RESULTS AND CONCLUSION: After 4 and 8 hours of culture, cell adhesion rate of the 13-DPS scaffold group was higher than that of the AFS and AYS scaffold groups (P<0.05). After 7 days of culture, cells of the 13-DPS scaffold group proliferated faster than those of AFS and AYS scaffold groups (P<0.05). Bone marrow mesenchymal stem cells adhered firmly and grew well on three kinds of scaffolds. Fibroblast-like growth was observed on the AFS and AYS scaffolds and chondrocyte-like growth was observed on the 3-DPS scaffold. After 3 weeks of cartilage induction, mRNA expression of COLIIα1, Aggrecan and Sox-9 was higher, and the mRNA expression of COLIα1 was lower, in the 3-DPS scaffold group compared with the other two groups (both P<0.05). After 3 weeks of cartilage induction, relative expression level of p-AKT and p-P38 in the 3-DPS scaffold group was significantly higher than that in the other two groups (both P<0.05). There were no significant differences in AKT total protein and ERK1/2, JNK, P38, p-ERK1/2, p-JNK and p-P38 protein expression levels among three groups. These findings suggest that nanofiber annulus fibrosus scaffolds with different spatial structures can induce the oriented differentiation of bone marrow mesenchymal stem cells through the P38 and AKT pathway, which were the downstream of the Integrin-FAK signaling pathway.