[Effect and mechanism of miR-124 on osteogenic differentiation of dental pulp mesenchymal stem cells].

PURPOSE: To evaluate the effect of microRNA (miR)-124 on osteogenic differentiation of dental pulp mesenchymal stem cells (DPSCs) and to explore the possible mechanism. METHODS: Logarithmic DPSCs were collected and divided into blank group, no-load group, miR-124 inhibitor group, miR-124 inhibitor combined with N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-ph (DAPT, Notch signaling pathway inhibitor) group. The blank group was not treated, the empty group was transfected with negative control vector inhibitor-NC, the miR-124 inhibitor group was transfected with miR-124 inhibitor, the miR-124 inhibitor combined with DAPT group was transfected with miR-124 inhibitor, and DAPT was added to make the final concentration of 5 µmol/L. The proliferation ability was tested by CCK-8 method 48 h after transfection. Alkaline phosphatase (ALP) activity was tested by p-nitrophenyl phosphate (P-NPP) method after 2 weeks of induction. The area of calcified nodules was tested by alizarin red staining method. The protein expression of hair-like division-related enhancer 1 (HEY1), hair-like division-related enhancer 2 (HEY2), and cyclin D1 gene (CCND1) were tested by Western blot. The data was analyzed by SPSS 19.0 software package. RESULTS: Compared with the blank group and no-load group, the A450 value at 24, 48, 72 h detected by CCK-8 experiment, A450 value of ALP activity, the area composition ratio of calcified nodules, and expression of HEY1, HEY2, and CCND1 in the miR-124 inhibitor group were increased (P<0.05). Compared with miR-124 inhibitor group, the A450 value at 24, 48, 72 h detected by CCK-8 experiment, A450 value of ALP activity, the area composition ratio of calcified nodules, and the expression of HEY1, HEY2, and CCND1 in the miR-124 inhibitor combined with DAPT group were significantly decreased(P<0.05). CONCLUSIONS: Down-regulation of miR-124 can promote osteogenic differentiation of DPSCs. It is speculated that the mechanism of action is related to the activation of Notch signaling pathway.

[Dental caries and periodontal diseases in adult Jiangxi cohort: a sample investigation].

PURPOSE: To investigate the current status of dental caries and periodontal diseases in the population aged 35-44 and 65-74 years in Jiangxi province, and to provide information for prevention of these diseases. METHODS: 1584 people (aged 35-44 and 65-74 years) were selected by equal-sized stratified multi- stage and random sampling. Their dental caries and periodontal diseases were examined in routine epidemiologic surgery manner. Student's t test and Chi-square test were applied for statistical analysis using SPSS12.0 software package. RESULTS: In the age group of 35-44 and 65-74 years, the prevalence rate of dental caries was 59.4% and 85.5%, the mean DMFT was 2.19 and 4.91, the prevalence rate of root caries was 32.7% and 79.5%, the mean DFRoot was 0.28 and 1.25,the rate of healthy periodontal tissues was 0.1% and 5.3%. CONCLUSIONS: Dental caries and periodontal diseases are quite common diseases in Jiangxi Province. We should reinforce the oral health care and the propaganda for oral care knowledge in order to treat caries and periodontal diseases better and earlier, and improve the life quality of middle-aged and elderly citizens.