periodontal tissue is a distinctive tissue structure composed three-dimensionally of cementum, periodontal ligament (pDL) and alveolar bone. Severe periodontal diseases cause fundamental problems for oral function and general health, and conventional dental treatments are insufficient for healing to healthy periodontal tissue. cell sheet technology has been used in many tissue regenerations, including periodontal tissue, to transplant appropriate stem/progenitor cells for tissue regeneration of a target site as a uniform tissue. However, it is still difficult to construct a threedimensional structure of complex tissue composed of multiple types of cells, and the transplantation of a single cell sheet cannot sufficiently regenerate a large-scale tissue injury. Here, we fabricated a three-dimensional complex cell sheet composed of a bone-ligament structure by layering pDL cells and osteoblast-like cells on a temperature responsive culture dish. following ectopic and orthotopic transplantation, only the complex cell sheet group was demonstrated to anatomically regenerate the bone-ligament structure along with the functional connection of PDL-like fibers to the tooth root and alveolar bone. this study represents successful three-dimensional tissue regeneration of a large-scale tissue injury using a bioengineered tissue designed to simulate the anatomical structure.
Peripheral nerve injury leads to sensory ganglion hyperexcitation, which increases neurotransmitter release and neuropathic pain. Botulinum toxin type A (BoNT/A) regulates pain transmission by reducing neurotransmitter release, thereby attenuating neuropathic pain. Despite multiple studies on the use of BoNT/A for managing neuropathic pain in the orofacial region, its exact mechanism of transport remains unclear. In this study, we investigated the effects of BoNT/A in managing neuropathic pain in two different animal models and its transport mechanism in the trigeminal nerve. Intraperitoneal administration of cisplatin induced bilateral neuropathic pain in the orofacial region, reducing the head withdrawal threshold to mechanical stimulation. Unilateral infraorbital nerve constriction (IONC) also reduced the ipsilateral head withdrawal threshold to mechanical stimulation. Unilateral peripheral administration of BoNT/A to the rat whisker pad attenuated cisplatin-induced pain behavior bilaterally. Furthermore, contralateral peripheral administration of BoNT/A attenuated neuropathy-induced behavior caused by IONC. We also noted the presence of BoNT/A in the blood using the mouse bioassay. In addition, the Alexa Fluor-488-labeled C-terminal half of the heavy chain of BoNT/A (BoNT/A-Hc) was localized in the neurons of the bilateral trigeminal ganglia following its unilateral administration. These findings suggest that axonal and hematogenous transport are involved in the therapeutic effects of peripherally administered BoNT/A in the orofacial region.
Tumor necrosis factor-alpha (TNF-α) is an infl ammatory cytokine known to cause bone resorption, swelling and edema during tissue organization. Conversely, TNF-α has also been shown to participate in tissue regeneration during the wound healing process. We have previously investigated the eff ects of TNF-α on human dental pulp cell diff erentiation. Dental pulp cells are composed of diff erent cell types including primary odontoblasts and fi broblasts. We determined that the ratio of stem cells within the pulp cell population was increased following short-term stimulation with TNF-α. The aim of this study therefore was to investigate the eff ect of short-term stimulation with TNF-α on osteoblast-like MC3T3-E1 cell growth and diff erentiation. MC3T3-E1 cells were cultured in standard growth medium and on reaching sub-confl uence were exposed to recombinant TNF-α (10 and 100 ng/ml) for 2 days prior to assessing their cell proliferation and diff erentiation properties in comparison to non-stimulated MC3T3-E1 cells (control). Although no signifi cant diff erences in cell proliferation were observed between the TNF-α-stimulated and control groups, cell diff erentiation was delayed in the TNF-α-stimulated groups. In summary, short-term stimulation of cultured MC3T3-E1 cells with TNF-α had only minimal eff ect on their growth and diff erentiation.
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