Objective: To investigate the differences in proliferation and osteogenic differentiation capacities between rat dental socket stem cells (DSCs) and periodontal ligament mesenchymal stem cells (PDLSCs), thereby providing a experimental basis for elucidating the functional characteristics of these two distinct sources of mesenchymal stem cells. Methods: This study was approved by the Institutional Animal Care and Use Committee. Twenty-four 6- to 8-week-old male Sprague-Dawley rats were divided into four groups (n = 6 per group) based on the time points of 0, 1, 3, and 7 days post-extraction by the random number table method. A rat alveolar socket model was established by extracting the left maxillary molars. Hematoxylin and eosin (H&E) staining was performed to observe the histomorphological changes in the alveolar sockets at the specified time points. Immunohistochemistry was used to detect the expression and distribution of the p75 neurotrophin receptor (P75NTR). Based on the staining results, an optimal time point was selected to harvest early healing tissues from the alveolar sockets. DSCs were cultured using a combination of tissue block and enzymatic digestion methods. Concurrently, PDLSCs were isolated from the extracted molars using identical culture protocols. The surface markers CD44, CD45, CD90, and P75NTR were analyzed via flow cytometry. Cell proliferation and clonogenic potential were compared using the Cell Counting Kit-8 (CCK-8) assay and colony formation assays, respectively. After adipogenic induction, Oil Red O staining was conducted to observe lipid droplet formation. Following osteogenic induction, alkaline phosphatase (ALP) activity and alizarin red S (ARS) staining were utilized to evaluate ALP expression and mineralized nodule formation, respectively. Furthermore, the mRNA and protein expression levels of osteogenesis-related factors, including ALP and Runt-related transcription factor 2 (RUNX2), were quantified to comprehensively assess the osteogenic differentiation potential of both cell types. Results: H&E staining revealed that the alveolar sockets were filled with erythrocytes 0 and 1 days post-extraction. By day 3, significant fibroblastic connective tissue proliferation was observed within the sockets, and bone formation increased markedly by day 7. Immunohistochemical analysis showed sparse P75NTR-positive staining limited to the inner socket wall 0 and 1 days post-extraction. On day 3, P75NTR was distributed throughout the fibrous connective tissue of the socket, with slight staining on the bone walls. By day 7, the receptor was expressed in the fibrous connective tissue at the edges of the trabeculae. Consequently, day 3 post-extraction was selected as the optimal time point for DSC isolation. Both PDLSCs and DSCs exhibited similar morphologies in vitro, characterized by high expression of mesenchymal stem cell markers (CD90, CD44) and P75NTR, alongside low expression of the hematopoietic marker CD45. CCK-8 assays demonstrated that the proliferation capacity of the DSCs was significantly higher than that of the PDLSCs (P < 0.05), accompanied by a greater colony formation rate (P < 0.001). Both cell types possessed adipogenic differentiation potential, as evidenced by vacuolar structures in the cytoplasm. Regarding osteogenesis, the DSCs exhibited a larger area and higher density of ALP staining (P < 0.001). ARS staining indicated that both cells formed orange-red mineralized nodules; however, the DSCs produced significantly more calcified nodules (P < 0.0001). Additionally, the mRNA and protein expression levels of ALP and RUNX2 were notably elevated in the DSCs compared with the PDLSCs (all P < 0.05). Conclusion Rat DSCs can be stably cultured in vitro. Compared with PDLSCs, DSCs exhibited superior capabilities in terms of proliferation, colony formation, and osteogenic differentiation.

Magnetic stimulation has made significant strides in the treatment of psychiatric disorders. Nonetheless, current magnetic stimulation techniques lack the precision to accurately modulate specific nuclei and cannot realize deep brain magnetic stimulation. To address this, we utilized superparamagnetic iron oxide nanoparticles as mediators to achieve precise targeting and penetration. We investigated the effects of magnetic fields with varying frequencies on neuronal activity and compared the activation effects on neurons using a 10-Hz precise magneto-stimulation system (pMSS) with repetitive transcranial magnetic stimulation in mice. Oxytocin levels, dendritic morphology and density, and mouse behavior were measured before and after pMSS intervention. Our findings suggest that pMSS can activate oxytocinergic neurons, leading to upregulation of oxytocin secretion and neurite outgrowth. As a result, sociability was rapidly improved after a one-week pMSS treatment regimen. These results demonstrate a promising magneto-stimulation method for regulating neuronal activity in deep brain nuclei and provide a promising therapeutic approach for autism spectrum disorder.
Animals ; Autism Spectrum Disorder/physiopathology* ; Paraventricular Hypothalamic Nucleus/physiology* ; Disease Models, Animal ; Transcranial Magnetic Stimulation/methods* ; Male ; Social Behavior ; Mice ; Oxytocin/metabolism* ; Mice, Inbred C57BL ; Neurons/physiology*