Rotator cuff tears (RCTs) are a leading cause of shoulder pain and dysfunction, often linked to oxidative stress and chronic inflammation. However, the molecular mechanisms underlying these pathological processes are not yet fully understood. S100A11, a calcium-binding protein of the S100 family, has been implicated in various inflammatory and degenerative diseases, but its role in RCTs is still unclear. In this study, we investigated the function of S100A11 in hydrogen peroxide H₂O₂-induced oxidative and inflammatory injury in human tenocytes. Our results demonstrated that S100A11 expression was significantly upregulated in tendon tissues from RCT patients. Knockdown of S100A11 markedly inhibited H₂O₂-induced inflammatory responses by reducing iNOS and PGE₂ levels and improved tenocyte viability. Furthermore, silencing S100A11 alleviated oxidative stress. Mechanistically, S100A11 knockdown activated the PI3K/Akt signaling pathway, suggesting a protective regulatory role. These findings highlight S100A11 as a potential therapeutic target for mitigating oxidative damage and promoting tendon repair in rotator cuff injuries.

This study aimed to collect the data on the roots and root canals of mandibular third molars of Japanese in order to provide diagnostic evidence for tooth transplantation by classifying their external root shape and root canal morphology. As specimens, 2,627 mandibular third molar teeth were used with computed tomography scanning and three-dimensional reconstruction. Of the 2,627 specimens, 1,444 were single root, and 1,183 were double root. Supernumerary roots were present in approximately 23.4% of all teeth, and the largest number of which had small root morphology and Type I root canal morphology. This study showed that most of the single and double roots had Type I root canal morphology, suggesting that the mandibular third molar is a reasonable choice as the donor tooth for tooth transplantation.

Mesenchymal stem cells were immortalized by introducing the telomerase gene, and clones with high differentiation potential were selected. Furthermore, Sox2, a transcription factor and neural stem cell marker, was introduced into these cells to establish a new stem cell line. This stem cell line proliferates indefinitely in stem cell culture medium and differentiates into cells expressing motor neuron-specific marker genes when cultured in neural differentiation medium. Transplantation of these stem cells into a rat spinal cord injury model restored walking ability and led to structural recovery of damaged spinal tissues. Furthermore, intravenous injection of the culture supernatant alone from this stem cell line into spinal cord-injured rats resulted in a recovery of motor function, with rats regaining the ability to walk. This culture supernatant contained over 10¹⁰ exosomes/ml, and these exosomes were found to contain large amounts of brain-derived neurotrophic factor.

Low-intensity pulsed ultrasound (LIPUS) is primarily used to treatment fractures in orthopedics. Several previous studies have shown that the P2X7 receptor plays a crucial role in the response to osteogenesis induced by mechanical stimulation, which is regulated by the nuclear factor of activated T cells c1 (NFATc1), an essential mediator. However, the effects of LIPUS, a mechanical stimulator, on the regulation of NFATc1 during osteogenesis have not been elucidated. In this study, we investigated the roles of the P2X7 receptor and NFATc1 in LIPUS-induced bone formation. LIPUS induces the expression of osteogenesis-related transcription factors, extracellular matrix proteins, and Ca²⁺ via the P2X7-NFATc1 pathway. These findings provide the first demonstration that LIPUS drives bone formation by activating P2X7-NFATc1 in osteoblasts.

Photobiomodulation (PBM) therapy using low-level lasers has been reported to promote wound healing and bone regeneration. However, fundamental studies on its effects in cortical bone healing remain limited. To investigate the effects of helium-neon (He-Ne) laser-induced PBM on cortical bone regeneration in a rat femoral defect model.

Cylindrical cortical bone defects were surgically created in both femora of rats. One side received He-Ne laser irradiation (632.8 nm, 25 mW, 5 min per session, 5 consecutive days), while the contralateral side served as the control. Bone healing was evaluated at 7 and 14 days postoperatively using micro-computed tomography (μ-CT) and histological analysis of non-decalcified sections. At day 7, μ-CT analysis showed no significant differences between the groups. However, histological evaluation revealed immature collagen-rich bone in the control group, whereas the laser-irradiated group exhibited more advanced mineralization. By day 14, the laser-irradiated group demonstrated significantly greater bone surface area and trabecular number, along with reduced trabecular thickness and spacing, indicating the formation of a finer and more complex trabecular structure. PBM with He-Ne laser may enhance cortical bone regeneration by promoting microarchitectural remodeling of newly formed bone. These findings support its potential to accelerate bone healing in critical-size defects.

Photobiomodulation (PBM) using red or near-infrared light modulates cellular functions, particularly mitochondrial activity, thereby contributing to tissue repair and angiogenesis. However, the impact of light-emitting diode (LED)-based PBM on human pericytes remains unclear. Human placenta-derived pericytes were cultured and irradiated with red LED light (655 nm, 5.6 J/cm²) four times at 1.5-hour intervals. Cell proliferation was assessed using the WST-8 assay at 3, 6, and 24 hours post-irradiation. Immunocytochemical analysis for angiogenesis-related markers (angiopoietin-1 [Ang-1], cluster of differentiation 146 [CD146], platelet-derived growth factor receptor beta [PDGFR-β], and vascular endothelial growth factor A [VEGF-A]) was performed at corresponding time points. Pericyte proliferation was significantly higher in the irradiated group than in controls at all time points (p < 0.05). Immunocytochemistry demonstrated greater expression of all four angiogenesis-related markers in the irradiated group, with peak levels at 24 hours post-irradiation. No temperature elevation was detected during LED exposure. Red LED PBM significantly stimulated metabolic activity and proliferation in human pericytes and upregulated key angiogenic markers, suggesting that PBM may promote wound healing and vascular regeneration by activating pericytes, thus offering a promising non-invasive strategy for tissue repair.