Novel Characterization of Constipation Phenotypes in ICR Mice Orally Administrated with Polystyrene Microplastics.

Indirect evidence has determined the possibility that microplastics (MP) induce constipation, although direct scientific proof for constipation induction in animals remains unclear. To investigate whether oral administration of polystyrene (PS)-MP causes constipation, an alteration in the constipation parameters and mechanisms was analyzed in ICR mice, treated with 0.5 µm PS-MP for 2 weeks. Significant alterations in water consumption, stool weight, stool water contents, and stool morphology were detected in MP treated ICR mice, as compared to Vehicle treated group. Also, the gastrointestinal (GI) motility and intestinal length were decreased, while the histopathological structure and cytological structure of the mid colon were remarkably altered in treated mice. Mice exposed to MP also showed a significant decrease in the GI hormone concentration, muscarinic acetylcholine receptors (mAChRs) expression, and their downstream signaling pathway. Subsequent to MP treatment, concentrations of chloride ion and expressions of its channel (CFTR and CIC-2) were decreased, whereas expressions of aquaporin (AQP)3 and 8 for water transportation were downregulated by activation of the mitogen-activated protein kinase (MAPK)/nuclear factor (NF)-κB signaling pathway. These results are the first to suggest that oral administration of PS-MP induces chronic constipation through the dysregulation of GI motility, mucin secretion, and chloride ion and water transportation in the mid colon.

Promoting Effects of Titanium Implants Coated with Dipterocarpus tuberculatus Extract on Osseointegration.

Titanium (Ti) is the most commonly used biomaterial for dental implants. When inserting Ti implants into jawbones, the main issue is the lack of strong bonding between the Ti implant and the host bone (osseointegration). Inspired by the outstanding adhesion performance of natural phenolic compounds on metal substrates and promoting effect for cell adhesion, we coated a natural plant extract, Dipterocarpus tuberculatus (MED), on Ti implants. We tested three groups of Ti plates and screw-shaped fixtures: nontreated Ti as commercially produced, ozone-treated Ti as commonly used surface modification for dental implants, and MED-coated Ti. Interestingly, the MED coating on the Ti plate preserved the surface wetting property for 20 days, whereas the hydrophilic wetting of ozone-treated Ti was readily transformed to hydrophobic within a day. Computerized tomography and histopathological analysis revealed that MED coating enhanced new bone tissue formation and regeneration. The gene expression level of integrin as a bone cell adhesion receptor and its downstream key regulators was significantly increased than that of ozone-treated Ti. Therefore, we suggest considering MED-mediated cell signaling pathways in screening natural products for cell adhesion and osseointegration, and MED as a suitable coating agent for improving Ti implantation.

In vivo impact assessment of orally administered polystyrene nanoplastics: biodistribution, toxicity, and inflammatory response in mice.

To assess the in vivo impact of nanoplastics (NP) and coagulation-based purified NP (PurNP), this study analyzed for alterations in the biodistribution, toxicity and inflammatory response in ICR mice exposed to three different doses of NP (5, 25, and 50 mg/kg) and PurNP for 2 weeks. Except water consumption, which was dose-dependently and significantly increased in all NP-treated groups, most factors assessed for feeding behaviors and excretions remained constant, without any significant change. Orally administered NP was detected in the intestine, kidneys, and liver at all concentrations, although the accumulation was higher in the intestine than in the kidneys and liver. No significant alterations were detected in the levels of serum biochemical markers and histopathological structures. However, compared to the vehicle group, expressions of the inflammatory response proteins (iNOS and COX-2) and mRNA levels of the inflammatory cytokines were remarkably increased in the liver, kidneys, and intestine of NP-treated mice. A similar increase was detected in the oxidative stress responses, including ROS concentration, SOD activity, and Nrf2 expression. Furthermore, similar inflammatory responses were observed in the PurNP-treated group, as compared to the vehicle-treated group. The results presented in this study provide the first strong evidence that oral administration of NP for 2 weeks results in high accumulation in the liver, kidneys, and intestine of ICR mice, and induces severe inflammatory and oxidative stress responses. These results additionally confirm the efficacy of water purification using the tannic acid-mediated coagulation removal technique.

A case of recurrent neuro-Behçet's disease after tooth extraction.

We report a 39-yr-old man with neuro-Behçet's disease (NBD) in remission who developed left-sided ataxia with a sensory deficit about 10 days after tooth extraction. Several years ago, he experienced a similar episode of relapse after tooth extraction. Brain magnetic resonance imaging showed a newly developed right thalamic lesion. In cerebrospinal fluid, lymphocyte-dominant pleocytosis and mild elevation of IgG were found. Immunologic factors may be important in the pathogenesis of NBD because of the time delay between tooth extraction and relapse. Careful observation and prevention are needed before dental procedures in patients with NBD.