BACKGROUND:Nowadays increasing experimental findings have proved that the low-frequency pulsed electromagnetic fields (LPEMF) can induce osteogenic differentiation of a variety of stem cells in the two-dimensional scaffold. However, little is reported on the LPEMF effect on the proliferation and osteogenic differentiation of stem cells in the three-dimensional scaffold.OBJECTIVE:To investigate the effect of LPEMF on the proliferation and osteogenic differentiation of human adipose-derived stem cells (hASCs) in the 3D Insert-PCL scaffold.METHODS:Passage 3 hASCs were directly cultured in the 3D Insert-PCL scaffolds folowed by LPEMF (50 Hz, 1 mT) exposure, 2 hours per day, for continuous 14 days (experimental group) or no intervention (control group). After 7 days of culture, Live/Dead staining was used to observe cell survival. After 1, 3, 5, 7 days of culture, MTT assay was used to detect cell proliferation. After 7 and 14 days of culture, the osteogenic differentiation of hASCs was assessed through the alkaline phosphatase (ALP) staining and qRT-PCR.RESULTS AND CONCLUSION: Live/dead cell staining proved that the hASCs had a good growth in the 3D Insert-PCL scaffolds as well as a high survival rate. The absorbance values of hASCs in the two groups were increased gradualy with time, and the absorbance value in the experimental group was significantly higher than that in the control group at 1 and 3 days after culture (P < 0.05). The ALP activity in the experimental group was stronger than that in the control group at 7 and 14 days after culture. qRT-PCR findings showed that at 7 days after culture, the mRNA levels of ALP and type Ⅰ collagen were significantly higher in the experimental group than the control group (P < 0.01), while at 14 days after culture, the mRNA levels of osteopontin, Runt-related transcription factor, ALP and type Ⅰ collagen were significantly higher in the experimental group than the control group (P < 0.05). To conclude, the LPEMF exposure can promote the proliferation and osteogenic differentiation of hASCs cultured on the the 3D Insert-PCL scaffold.

From synchronous metastasis to metachronous metastasis and from oligometastasis to disseminated metastasis, distant metastatic nasopharyngeal carcinoma (stage IV B) has great heterogeneity. The prognosis of stage IV B nasopharyngeal carcinoma patients with distant metastases is closely related to the anatomical characteristics of metastases. Therefore, it is necessary to subdivide M 1 stage to lay the foundation for individualized treatment of patients with metastatic nasopharyngeal carcinoma. In addition to systemic chemotherapy, the primary tumors and metastatic lesions should be considered during the treatment of newly-diagnosed metastatic nasopharyngeal carcinoma. Currently, there is a lack of recognized treatment modes for newly-diagnosed stageⅣ B nasopharyngeal carcinoma, and more studies are needed to evaluate the clinical benefits of different treatment methods.