BACKGROUND: Metabolic Dysfunction-associated Steatotic Liver Disease (MASLD) has become a global epidemic, and air pollution has been identified as a potential risk factor. This study aims to investigate the non-linear relationship between ambient air pollution and MASLD prevalence. METHOD: In this cross-sectional study, participants undergoing health checkups were assessed for three-year average air pollution exposure. MASLD diagnosis required hepatic steatosis with at least 1 out of 5 cardiometabolic criteria. A stepwise approach combining data visualization and regression modeling was used to determine the most appropriate link function between each of the six air pollutants and MASLD. A covariate-adjusted six-pollutant model was constructed accordingly. RESULTS: A total of 131,592 participants were included, with 40.6% met the criteria of MASLD. "Threshold link function," "interaction link function," and "restricted cubic spline (RCS) link functions" best-fitted associations between MASLD and PM_2.5, PM₁₀/CO, and O₃ /SO₂/NO₂, respectively. In the six-pollutant model, significant positive associations were observed when pollutant concentrations were over: 34.64 µg/m³ for PM_2.5, 57.93 µg/m³ for PM₁₀, 56 µg/m³ for O₃, below 643.6 µg/m³ for CO, and within 33 and 48 µg/m³ for NO₂. The six-pollutant model using these best-fitted link functions demonstrated superior model fitting compared to exposure-categorized model or linear link function model assuming proportionality of odds. CONCLUSION Non-linear associations were found between air pollutants and MASLD prevalence. PM_2.5, PM₁₀, O₃, CO, and NO₂ exhibited positive associations with MASLD in specific concentration ranges, highlighting the need to consider non-linear relationships in assessing the impact of air pollution on MASLD.
Humans ; Nitrogen Dioxide ; Cross-Sectional Studies ; Air Pollution/analysis* ; Air Pollutants/analysis* ; Particulate Matter/analysis* ; Liver Diseases ; Environmental Exposure/analysis*

The reduction of nitrate to nitrite by the oral microbiota has been proposed to be important for oral health and results in nitric oxide formation that can improve cardiometabolic conditions. Studies of bacterial composition in subgingival plaque suggest that nitrate-reducing bacteria are associated with periodontal health, but the impact of periodontitis on nitrate-reducing capacity (NRC) and, therefore, nitric oxide availability has not been evaluated. The current study aimed to evaluate how periodontitis affects the NRC of the oral microbiota. First, 16S rRNA sequencing data from five different countries were analyzed, revealing that nitrate-reducing bacteria were significantly lower in subgingival plaque of periodontitis patients compared with healthy individuals (P < 0.05 in all five datasets with n = 20-82 samples per dataset). Secondly, subgingival plaque, saliva, and plasma samples were obtained from 42 periodontitis patients before and after periodontal treatment. The oral NRC was determined in vitro by incubating saliva with 8 mmol/L nitrate (a concentration found in saliva after nitrate-rich vegetable intake) and compared with the NRC of 15 healthy individuals. Salivary NRC was found to be diminished in periodontal patients before treatment (P < 0.05) but recovered to healthy levels 90 days post-treatment. Additionally, the subgingival levels of nitrate-reducing bacteria increased after treatment and correlated negatively with periodontitis-associated bacteria (P < 0.01). No significant effect of periodontal treatment on the baseline saliva and plasma nitrate and nitrite levels was found, indicating that differences in the NRC may only be revealed after nitrate intake. Our results suggest that an impaired NRC in periodontitis could limit dietary nitrate-derived nitric oxide levels, and the effect on systemic health should be explored in future studies.
Humans ; Nitrates ; Nitric Oxide ; Nitrites ; RNA, Ribosomal, 16S/genetics* ; Periodontitis/microbiology* ; Bacteria ; Dental Plaque/microbiology* ; Saliva/microbiology* ; Microbiota/genetics*

To analyze the association between exposure to air pollution and respiratory disease of primary school students in Chongqing City. Eight districts and counties were randomly selected based on the air pollution situation in Chongqing City. In each selected district and county, one primary school was randomly selected. A questionnaire survey was conducted on all primary school students in Grades 3-5 by the end of 2019. Air quality data from the nearest environmental monitoring sites were collected. A logistic regression model was used to analyze the impact of the living environment, lifestyle and air pollution on the respiratory disease of surveyed students. This study included 5 918 primary school students, with a prevalence rate of respiratory disease of 21.54%. The prevalence rates of boys and girls were 23.38% and 19.59%, respectively. The average Air quality index (AQI) of the surveyed school was 67, and the rates of exceeding standards of PM₁₀, PM_2.5, NO₂ and O₃ were 1.16%, 6.92%, 0.99% and 5.65%, respectively. The level of SO₂ and CO did not exceed the standard. After adjusting for relevant factors, logistic regression analysis showed that primary school students in areas with high exposure to air pollution (OR=2.52), using air pollution related-chemicals at home (OR=1.47), passive smoking (OR=1.27), and keeping pets at home (OR=1.18) had a higher risk of respiratory disease (all P<0.05). In addition, the average annual values of AQI (OR=1.18), PM₁₀ (OR=1.20), PM_2.5 (OR=1.35), and NO₂ (OR=1.11) increased the risk of respiratory diseases in primary school students (all P<0.05). In conclusion, the respiratory disease of primary school students in Chongqing City is related to the living environment, behavior habits and ambient air quality. The increased exposure concentration of PM₁₀, PM_2.5 and NO₂ in air pollutants can lead to an increased risk of respiratory disease among primary school students.
Female ; Humans ; Male ; Air Pollution/adverse effects* ; Nitrogen Dioxide ; Particulate Matter ; Respiratory Tract Diseases/epidemiology* ; Schools ; Students ; Child

Nitrogen dioxide (NO₂) is an important indoor air pollutant, with both outdoor and indoor sources contributing to indoor NO₂ exposure levels. Considering the association of high NO₂ exposure with adverse health effects, the Standards for indoor air quality (GB/T 18883-2022) have been revised to further restrict indoor NO₂ limit values. The 1-h average concentration limit value for NO₂ has been reduced from 0.24 mg/m³ to 200 μg/m³.This study analyzed the technical contents related to the determination of the limits of indoor NO₂ in Standards for Indoor Air Quality (GB/T 18883-2022), including source, exposure level, health effects, and the process and evidence basis for determining the limit value. It also proposed prospects for the direction for the implementation of the indoor NO₂ standard.
Humans ; Air Pollution, Indoor/adverse effects* ; Nitrogen Dioxide ; Air Pollutants/analysis* ; China ; Air Pollution/adverse effects*

To analyze the association between exposure to air pollution and respiratory disease of primary school students in Chongqing City. Eight districts and counties were randomly selected based on the air pollution situation in Chongqing City. In each selected district and county, one primary school was randomly selected. A questionnaire survey was conducted on all primary school students in Grades 3-5 by the end of 2019. Air quality data from the nearest environmental monitoring sites were collected. A logistic regression model was used to analyze the impact of the living environment, lifestyle and air pollution on the respiratory disease of surveyed students. This study included 5 918 primary school students, with a prevalence rate of respiratory disease of 21.54%. The prevalence rates of boys and girls were 23.38% and 19.59%, respectively. The average Air quality index (AQI) of the surveyed school was 67, and the rates of exceeding standards of PM₁₀, PM_2.5, NO₂ and O₃ were 1.16%, 6.92%, 0.99% and 5.65%, respectively. The level of SO₂ and CO did not exceed the standard. After adjusting for relevant factors, logistic regression analysis showed that primary school students in areas with high exposure to air pollution (OR=2.52), using air pollution related-chemicals at home (OR=1.47), passive smoking (OR=1.27), and keeping pets at home (OR=1.18) had a higher risk of respiratory disease (all P<0.05). In addition, the average annual values of AQI (OR=1.18), PM₁₀ (OR=1.20), PM_2.5 (OR=1.35), and NO₂ (OR=1.11) increased the risk of respiratory diseases in primary school students (all P<0.05). In conclusion, the respiratory disease of primary school students in Chongqing City is related to the living environment, behavior habits and ambient air quality. The increased exposure concentration of PM₁₀, PM_2.5 and NO₂ in air pollutants can lead to an increased risk of respiratory disease among primary school students.
Female ; Humans ; Male ; Air Pollution/adverse effects* ; Nitrogen Dioxide ; Particulate Matter ; Respiratory Tract Diseases/epidemiology* ; Schools ; Students ; Child

Nitrogen dioxide (NO₂) is an important indoor air pollutant, with both outdoor and indoor sources contributing to indoor NO₂ exposure levels. Considering the association of high NO₂ exposure with adverse health effects, the Standards for indoor air quality (GB/T 18883-2022) have been revised to further restrict indoor NO₂ limit values. The 1-h average concentration limit value for NO₂ has been reduced from 0.24 mg/m³ to 200 μg/m³.This study analyzed the technical contents related to the determination of the limits of indoor NO₂ in Standards for Indoor Air Quality (GB/T 18883-2022), including source, exposure level, health effects, and the process and evidence basis for determining the limit value. It also proposed prospects for the direction for the implementation of the indoor NO₂ standard.
Humans ; Air Pollution, Indoor/adverse effects* ; Nitrogen Dioxide ; Air Pollutants/analysis* ; China ; Air Pollution/adverse effects*

OBJECTIVE: To investigate the anti-oxidant and anti-inflammatory effects of ethanol extract of Polygala sibirica L. var megalopha Fr. (EEP) on RAW264.7 mouse macrophages. METHODS: RAW264.7 cells were pretreated with 0-200 µg/mL EEP or vehicle for 2 h prior to exposure to 1 µg/mL lipopolysaccharide (LPS) for 24 h. Nitric oxide (NO) and prostaglandin (PGE₂) production were determined by Griess reagent and enzyme-linked immunosorbent assay (ELISA), respectively. The mRNA levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor α (TNF-α), interleukin-1beta (IL-1β), and IL-6 were determined using reverse transcription polymerase chain reaction (RT-PCR). Western blot assay was used to determine the protein expressions of iNOS, COX-2, phosphorylation of extracellular regulated protein kinases (ERK1/2), c-Jun N-terminal kinase (JNK), inhibitory subunit of nuclear factor Kappa B alpha (Iκ B-α) and p38. Immunofluorescence was used to observe the nuclear expression of nuclear factor-κ B p65 (NF-κ B p65). Additionally, the anti-oxidant potential of EEP was evaluated by reactive oxygen species (ROS) production and the activities of catalase (CAT) and superoxide dismutase (SOD). The 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl (OH), superoxide anion (O₂^-) radical and nitrite scavenging activity were also measured. RESULTS: The total polyphenol and flavonoid contents of EEP were 23.50±2.16 mg gallic acid equivalent/100 g and 43.78±3.81 mg rutin equivalent/100 g. With EEP treatment (100 and 150 µg/mL), there was a notable decrease in NO and PGE₂ production induced by LPS in RAW264.7 cells by downregulation of iNOS and COX-2 mRNA and protein expressions (P<0.01 or P<0.05). Furthermore, with EEP treatment (150 µg/mL), there was a decrease in the mRNA expression levels of TNF-α, IL-1β and IL-6, as well as in the phosphorylation of ERK, JNK and p38 mitogen-activated protein kinase (MAPK, P<0.01 or P<0.05), by blocking the nuclear translocation of NF-κ B p65 in LPS-stimulated cells. In addition, EEP (100 and 150 µg/mL) led to an increase in the anti-oxidant enzymes activity of SOD and CAT, with a concomitant decrease in ROS production (P<0.01 or P<0.05). EEP also indicated the DPPH, OH, O₂^- radical and nitrite scavenging activity. CONCLUSION EEP inhibited inflammatory responses in activated macrophages through blocking MAPK/NF-κ B pathway and protected against oxidative stress.
Animals ; Mice ; Antioxidants/pharmacology* ; Lipopolysaccharides/pharmacology* ; Polygala ; Transcription Factor RelA/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Ethanol/chemistry* ; Interleukin-6/metabolism* ; Anti-Inflammatory Agents/chemistry* ; Reactive Oxygen Species/metabolism* ; Cyclooxygenase 2/metabolism* ; Nitrites/metabolism* ; NF-kappa B/metabolism* ; Nitric Oxide/metabolism* ; Superoxide Dismutase/metabolism* ; RNA, Messenger ; Nitric Oxide Synthase Type II/metabolism*

In the central nervous system, nitric oxide (NO), a free gas with multitudinous bioactivities, is mainly produced from the oxidation of L-arginine by neuronal nitric oxide synthase (nNOS). In the past 20 years, the studies in our group and other laboratories have suggested a significant involvement of nNOS in a variety of neurological and neuropsychiatric disorders. In particular, the interactions between the PDZ domain of nNOS and its adaptor proteins, including post-synaptic density 95, the carboxy-terminal PDZ ligand of nNOS, and the serotonin transporter, significantly influence the subcellular localization and functions of nNOS in the brain. The nNOS-mediated protein-protein interactions provide new attractive targets and guide the discovery of therapeutic drugs for neurological and neuropsychiatric disorders. Here, we summarize the work on the roles of nNOS and its association with multiple adaptor proteins on neurological and neuropsychiatric disorders.
Humans ; Nitric Oxide Synthase Type I/metabolism* ; Adaptor Proteins, Signal Transducing ; Brain/metabolism* ; Nervous System Diseases

We reported the discovery of six novel coumarins, toddasirins A-F (1-6), each endowed with modified isoprenyl or geranyl side chains, derived from the roots of Toddalia asiatica. Comprehensive structural elucidation was achieved through multispectroscopic analyses, single-crystal X-ray diffraction experiments, and advanced quantum mechanical electronic circular dichroism (ECD) calculations. Furthermore, the anti-inflammatory activity of these compounds was assessed. Notably, compounds 1-3 and 6 demonstrated notable inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-induced RAW 264.7 cells, with 50% inhibitory concentration (IC₅₀) values of 3.22, 4.78, 8.90, and 4.31 μmol·L^-1, respectively.
Mice ; Animals ; Coumarins/chemistry* ; Rutaceae/chemistry* ; Anti-Inflammatory Agents/pharmacology* ; Plant Extracts/chemistry* ; RAW 264.7 Cells ; Nitric Oxide ; Molecular Structure

Five new racemic N-acetyldopamine (NADA) trimers, asponchimides A-E (1-5), were isolated from Aspongopus chinensis, a prominent traditional Chinese medicinal insect employed for alleviating pain, treating indigestion, and addressing kidney ailments. Compounds 1-5 were successfully resolved by chiral high-performance liquid chromatography (HPLC), yielding five pairs of enantiomers: (+)- and (-)-asponchimides A-E (1a/1b-5a/5b). Their structural identities were discerned by extensive spectroscopic analyses, including high-resolution mass spectrometry (HRMS), ultraviolet-visible (UV-Vis) spectroscopy, infrared (IR) spectroscopy, and nuclear magnetic resonance (NMR), and their absolute configurations were determined by electronic circular dichroism (ECD) calculations. Compounds 1-5 are pioneering instances of NADA trimers featuring a Δ⁷ double bond. When subjected to a series of bioassays, a majority of the compounds exhibited weak inhibitory activity against nitric oxide (NO) production in LPS-induced RAW 264.7 cells.
Molecular Structure ; Magnetic Resonance Spectroscopy ; Dopamine ; Nitric Oxide