The Fungal Metabolite (+)-Terrein Abrogates Ovariectomy-Induced Bone Loss and Receptor Activator of Nuclear Factor-kappa B Ligand-Induced Osteoclastogenesis by Suppressing Protein Kinase-C alpha/beta II Phosphorylation

Osteoporosis is a common disease characterized by a systemic impairment of bone mass and microarchitecture that results in fragility fractures. Severe bone loss due to osteoporosis triggers pathological fractures and consequently decreases the daily life activity and quality of life. Therefore, prevention of osteoporosis has become an important issue to be addressed. We have reported that the fungal secondary metabolite (+)-terrein (TER), a natural compound derived from Aspergillus terreus, has shown receptor activator of nuclear factor-kappa B ligand (RANKL)-induced osteoclast differentiation by suppressing nuclear factor of activated T-cell 1 (NFATc1) expression, a master regulator of osteoclastogenesis. TER has been shown to possess extensive biological and pharmacological benefits; however, its effects on bone metabolism remain unclear. In this study, we investigated the effects of TER on the femoral bone metabolism using a mouse-ovariectomized osteoporosis model (OVX mice) and then on RANKL signal transduction using mouse bone marrow macrophages (mBMMs). In vivo administration of TER significantly improved bone density, bone mass, and trabecular number in OVX mice (p < 0.01). In addition, TER suppressed TRAP and cathepsin-K expression in the tissue sections of OVX mice (p < 0.01). In an in vitro study, TER suppressed RANKL-induced phosphorylation of PKC alpha/beta II, which is involved in the expression of NFATc1 (p < 0.05). The PKC inhibitor, GF109203X, also inhibited RANKL-induced osteoclastogenesis in mBMMs as well as TER. In addition, TER suppressed the expression of osteoclastogenesis-related genes, such as Ocstamp, Dcstamp, Calcr, Atp6v0d2, Oscar, and Itgb3 (p < 0.01). These results provide promising evidence for the potential therapeutic application of TER as a novel treatment compound against osteoporosis

Resolvin D2 Induces Resolution of Periapical Inflammation and Promotes Healing of Periapical Lesions in Rat Periapical Periodontitis

Periapical periodontitis results from pulpal infection leading to pulpal necrosis and resorption of periapical bone. The current treatment is root canal therapy, which attempts to eliminate infection and necrotic tissue. But, in some cases periapical inflammation doesn't resolve even after treatment. Resolvins belongs to a large family of specialized pro-resolving lipid mediators that actively resolves inflammation signaling via specific receptors. Resolvin D2 (RvD2), a metabolite of docosahexaenoic acid (DHA), was tested as an intracanal medicament in rats in vivo. Mechanism was evaluated in rat primary dental pulp cells (DPCs) in vitro. The results demonstrate that RvD2 reduces inflammatory cell infiltrate, periapical lesion size, and fosters pulp like tissue regeneration and healing of periapical lesion. RvD2 enhanced expression of its receptor, GPR18, dentin matrix acidic phosphoprotein 1 (DMP1) and mineralization in vivo and in vitro. Moreover, RvD2 induces phosphorylation of Stat3 transcription factor in dental pulp cells. We conclude that intracanal treatment with RvD2 resolves inflammation and promoting calcification around root apex and healing of periapical bone lesions. The data suggest that RvD2 induces active resolution of inflammation with pulp-like tissue regeneration after root canal infection and thus maybe suitable for treating periapical lesions

Analysis of Radioactive Elements in Testes of Large Japanese Field Mice Using an Electron Probe Micro-Analyser after the Fukushima Accident

The Fukushima Daiichi nuclear power plant (FDNPP) accident drew global attention to the health risks of radiation exposure. The large Japanese field mice (Apodemus speciosus) are rodents endemic to, and distributed throughout, Japan. This wild rodent live in and around the ex-evacuation zone on the ground surface and/or underground. In this study, we evaluated the effect of chronic radiation exposure associated with FDNPP accident on the testes of large Japanese field mice. Morphological analysis and electron-prove X-ray microanalysis (EPMA) was undertaken on the testes. Morphological analysis of testes based on H&E staining showed that the spermatogenesis was observed normally in the breeding season of wild mice in the heavily contaminated area. However, caesium (Cs) was not detected in all testes of wild mice from FDNPP ex-evacuation zone. In conclusion, even if the testes and the process of spermatogenesis are hypersensitive to radiation, we could not detect radiation effects on the spermatogenesis and Cs in the examined large Japanese field mice testes following chronic radiation exposure associated with the FDNPP accident

Topical application of lithium chloride on the pulp induces dentin regeneration.

We herein describe a novel procedure for dentin regeneration that mimics the biological processes of tooth development in nature. The canonical Wnt signaling pathway is an important regulator of the Dentin sialophosphoprotein (Dspp) expression. Our approach mimics the biological processes underlying tooth development in nature and focuses on the activation of canonical Wnt signaling to trigger the natural process of dentinogenesis. The coronal portion of the dentin and the underlying pulp was removed from the first molars. We applied lithium chloride (LiCl), an activator of canonical Wnt signaling, on the amputated pulp surface to achieve transdifferentiation toward odontoblasts from the surrounding pulpal cells. MicroCT and microscopic analyses demonstrated that the topical application of LiCl induced dentin repair, including the formation of a complete dentin bridge. LiCl-induced dentin is a tubular dentin in which the pulp cells are not embedded within the matrix, as in primary dentin. In contrast, a dentin bridge was not induced in the control group treated with pulp capping with material carriers alone, although osteodentin without tubular formation was induced at a comparatively deeper position from the pulp exposure site. We also evaluated the influence of LiCl on differentiation toward odontoblasts in vitro. In the mDP odontoblast cell line, LiCl activated the mRNA expression of Dspp, Axin2 and Kallikrein 4 (Klk4) and downregulated the Osteopontin (Osp) expression. These results provide a scientific basis for the biomimetic regeneration of dentin using LiCl as a new capping material to activate dentine regeneration

Histological micrographs (H-E) of sagittal sections of the first upper molars.

<p>Reparative dentin formation was evaluated on the serial sections in the control (A-E) and LiCl (F-J) groups at four weeks after pulpotomy. (A,F) Pulpotomy was performed in the first molars (M1), and the coronal part of the pulp was removed (asterisk). (B) In the control molars, no reparative dentin bridges were observed beneath the pulp exposure site. However, hard reparative tissue was detected along the residual root dentin surface (arrows). (C) Higher magnification view of the dot box in panel B. Necrotic and disintegrated tissue was observed just beneath the pulp exposure site (arrow heads). (D,E) Bright (D) and dark (E) field images at higher magnification of the solid box in panel B. Dentin tubules were observed in the residual dentin (de), whereas a tubular structure was hardly detected in the deposited reparative tissue (rd). (F-G) The LiCl group exhibited dentin bridges beneath the exposed surface, and the reparative tissue further expanded in the direction of the apex (red arrows). (H) Higher magnification view of the dot box in panel G. A tubular structure was evident in the dentin bridges (red arrows), with only a few cells entrapped in the matrix. (I,J) Bright (I) and dark (J) field images at higher magnification of the solid box in panel G. The reparative matrix in the LiCl group was more condensed, with a well-developed tubular structure, than that observed in the control group. The figure represented the similar results from independent samples. Abbreviations: M1, the first upper molar; mr, mesial root; ab, alveolar bone; de, dentin; pu, pulp; rd, regenerative dentin, db, dentin bridge. Scale bars, 100 μm in A,F; 50 μm in B,G; 20 μm in C,H; 10 μm in D,E,I,J.</p

<i>In situ</i> hybridization for <i>Dspp</i> mRNA in the pulp in the LiCl group.

<p>(A) The <i>Dspp</i> mRNA expression was confirmed in the pulp cells beneath the dentin bridges. (B) Higher magnification image of the solid box in panel A showing the <i>Dspp</i> mRNA expression in the pulp cells. Abbreviations: de, dentin; pu, pulp; rd, regenerative dentin, db, dentin bridge. Arrowheads indicate Dspp transcripts. Scale bars, 50 μm in A; 10 μm in B.</p