Ulcerative colitis (UC) is a chronic, nonspecific inflammatory bowel disease (IBD) characterized by complicated and relapsing inflammation in the gastrointestinal tract. SM934 is a water-soluble artemisinin analogue that shows anti-inflammatory and immuno-regulatory effects. In this study, we investigated the effects of SM934 on UC both in vivo and in vitro. A mouse model of colitis was established in mice by oral administration of 5% dextran sulfate sodium (DSS). SM934 (3, 10 mg/kg per day, ig) was administered to the mice for 10 days. After the mice were sacrificed, colons, spleens and mesenteric lymph nodes (MLNs) were collected for analyses. We showed that SM934 administration restored DSS-induced body weight loss, colon shortening, injury and inflammation scores. Furthermore, SM934 administration significantly decreased the disease activity index (DAI), histopathological scores, and myeloperoxidase (MPO) activities in colonic tissues. Moreover, SM934 administration dose-dependently decreased the mRNA and protein levels of DSS-induced pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α), and the percentage of macrophages and neutrophils in colon tissues. The effects of SM934 on LPS-stimulated RAW 264.7 cells and THP-1-derived macrophages were examined in vitro. Treatment with SM934 (0.8, 8, 80 μmol/L) dose-dependently decreased the production of pro-inflammatory mediators in LPS-stimulated RAW264.7 cells and THP-1-derived macrophages via inhibiting activation of the NF-κB signaling. Our results reveal the protective effects of SM934 on DSS-induced colitis can be attributed to its suppressing effects on neutrophils and macrophages and its inhibitory role in the NF-κB signaling, suggests that SM934 might be a potential effective drug for ulcerative colitis.
It is well-known that attractive electromagnetic interference (EMI) shielding performance depends on functional (e.g., electrical and magnetic) fillers and structural designs. This paper presents a novel three-layered sandwich structure of poly(vinylidene fluoride) (PVDF)-based nanocomposites, consisting of graphene nanoplatelets (GNP), nickel (Ni), and carbon nanotubes (CNT). The unique three-layered sandwich structure of GNP-Ni-CNT exhibited excellent EMI shielding ability due to the several interfaces of the multilayered structure with electric loss by the conductive fillers and magnetic loss by the magnetic filler. The overall shielding performance could be further improved by increasing the overall thickness and the number of layers. With a fixed thickness of 0.6 mm, the shielding effectiveness of the PVDF/GNP-Ni-CNT three-layered and six-layered structure composite at 15 GHz was 41.8 and 46.4 dB, respectively. These results provide a useful strategy to prepare various EMI shielding materials with a sandwich structure, presenting tremendous opportunities to design and manufacture advanced EMI shielding materials and equipment.
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