Effect of small molecule hydrogels on proliferation, apoptosis and myocardial differentiation of bone marrow mesenchymal stem cells / 中国组织工程研究

ABSTRACT

BACKGROUND:A short-peptide small molecule hydrogel (SMH) developed in the previous study has more obvious advantages than other hydrogels to improve local microenvironment, carry bioactive substances and interfere with stem cell signal transduction pathways. OBJECTIVE:To explore the effect of SMHs on bone marrow mesenchymal stem cells (BMSCs) proliferation, apoptosis and differentiation into myocardial cells. METHODS: (1) Passage 9 rat BMSCs in vitro were divided into control group and experimental group, followed by routine culture and culture in SMHs, respectively. At 7 days of culture, cell proliferation and apoptosis were detected. Cells in the two groups were exposed to anaerobic environment for 12 hours, and expression levels of Bcl-2, Bax and Caspase-3 in BMSCs were detected. (2) Passage 9 BMSCs were divided into four groups and then cultured in 5-azacytidine, SMHs, SMHs+5-azacytidine, and L-DMEM (normal control), respectively. After 4 weeks of induction, expression of CTnT, desmin and Cx-43 proteins was detected and expression levels of early cardiac transcription factors, NKX2.5 and GATA-4, were also measured. RESULTS AND CONCLUSION: (1) Compared with the control group, better proliferation and lower apoptosis of BMSCs were found in the experimental group. Under anaerobic conditions, the number of survival cells was reduced in both groups, but less apoptosis or necrosis was found in the experimental group than the control group (P < 0.05). Moreover, the level of Bcl-2 was higher in the experimental group than the control group (P < 0.01), while the levels of Bax and Caspases-3 protiens were lower in the experimental group than the control group (P < 0.01). (2) NKx2.5 and GATA-4 mRNA expression was found in both 5-azacytidine and SMHs+5-azacytidine groups, and moreover, the mRNA levels of early cardiac transcription factors were significantly higher in the SMHs+5-azacytidine group than in the 5-azacytidine group (P < 0.05). In the normal control group, cTnT expressed negatively, and desmin and Cx-43 expressed weakly. The expression of cTnT, desmin and Cx-43 proteins was higher in the SMHs+5-azacytidine group than in the 5-azacytidine and SMHs groups, while there was no significant difference between the latter two groups. To conclude, SMHs as a culture medium is conducive to the proliferation of BMSCs, reduces cell apoptosis, and promotes myocardial differentiation of BMSCs.