Biological characteristics of dental pulp stem cells induced by lipopolysaccharide / 中国组织工程研究

ABSTRACT

BACKGROUND: During the decay process, the bacteria and toxins invade dental pulp tissue along the dentin tubule. Dental pulp stem cells proliferate and migrate to the damaged point, forming reparative dentin to avoid stimulations from bacteria outside. Lipopolysaccharide is the main component of gram-negative bacteria. Whether lipopolysaccharide affects the proliferation, migration, and odontoblastic ability of dental pulp stem cells remains to be studied. OBJECTIVE: To investigate the proliferation, migration and odontoblastic abilities in dental pulp stem cells induced by lipopolysacchari de. METHODS: Primary cultured dental pulp stem cells were stimulated by 0, 0.1,1 and 10 mg/L lipopolysaccharide. The proliferation of dental pulp stem cells was detected by MTT assay. Scratch test and Transwell assay were performed to test the migration of dental pulp stem cells. Dental pulp stem cells were cultured in mineralized solution and 1 mg/L lipopolysaccharide for 21 days. The mineralized nodule formation was detected by alizarin red staining. RT-PCR was performed to detect the expression of dentin related genes. RESULTS AND CONCLUSION: The absorbance value in the 0.1, 1 and 10 mg/L lipopolysaccharide groups at 1, 3, 5 and 7 days was significant lower than that in the 0 mg/L lipopolysaccharide group (P < 0.01), and the migration ability was higher than that in the 0 mg/L lipopolysaccharide group. After 12 days of mineralized induction, the number and area of mineralized nodule formation in the 1 mg/L lipopolysaccharide group were significantly lower than those in the 0 mg/L lipopolysaccharide group (P < 0.01). The mRNA expression levels of osteocalcin, bone sialoprotein, and alkaline phosphatase in the 1 mg/L lipopolysaccharide group were significantly lower than those in the 0 mg/L lipopolysaccharide group (P < 0.01). These results indicate that lipopolysaccharide treatment inhibits the proliferation and odontoblastic ability of dental pulp stem cells but promotes the cell migration ability.