Context
Periplaneta americana
L. (Blattariae) is used as a treatment for ulcerative colitis (UC) in Chinese traditional medicine.
Objective
To evaluate the antioxidative activity of
P. americana
whole body ethanol extract (PAE) on UC mice and whether glycine and proline could be used for quality control and identification of active PAE components.
Materials and methods
NCM460 cells were pre-incubated in PAE, AA-L, AA-M, and AA-H (low, high and medium doses of proline and glycine), then treated with recombinant human TNF-α. The glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen (ROS) levels were determined. UC mice were fed with water containing 2.5% dextran sulfate sodium (w/v) after pre-treatment with different doses of PAE once a day for 7 days. ELISA was used to detect the concentrations of inflammation-related factors. Colon tissues of mice were used to detect the activity of myeloperoxidase (MPO), GSH, MDA, and SOD. Histological changes were observed using H&E staining. The expression of target proteins was determined by western blotting.
Results
In vivo
, PAE treatment reduced the DAI score more than in the model group, restoring the weight and colonic length. It also reduced the severity of colitis, and inflammatory and oxidative stress intensity. Additionally, western blotting showed that the Nrf2 pathway was activated by PAE.
In vitro
PAE significantly alleviated TNF-α-induced cell damage and oxidative stress, which is relevant to the activation of the Nrf2 pathway.
Conclusions
PAE may relieve oxidative stress through the Nrf2 signaling pathway, and proline and glycine may be used as active components of its antioxidative stress activity.
In this paper, the finite element (FE) method was used for simulation of the low-frequency sound field in high speed train compartments. The proposed model was validated using experimental results. The FE models of the train compartments with and without racks were established respectively, and the sound pressure level of the standard point and sound field distribution in these two cases were compared. The results showed that the A-weighted sound pressure level of the standard point was 1.2 dB lower when there is no rack in the compartment.
When finite element method was adopted in acoustic analysis, area source was defaulted to be of the same amplitude and phase in its whole region. While in practical, there are differences in amplitude and phase between different parts of the area. In this paper, the area source was divided into several sub-area sources so that the source can be modeled with higher accuracy. The optimized area sources were used in simulation of interior sound field of high-speed train. Calculations prove that the simulated result has very good agreement with the measured one.
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