Background Salidroside (SAL) has a protective effect on multiple organ systems. Exposure to fine particulate matter (PM_2.5) in the atmosphere may lead to disruptions in gut microbiota and impact intestinal health. The regulatory effect of SAL on the gut microbiota of mice exposed to PM_2.5 requires further investigation. Objective To evaluate gut microbiota disruption in mice after being exposed to PM_2.5 and the potential effect of SAL. Methods Forty male C57BL/6 mice, aged 6 to 8 weeks, were randomly divided into four groups: a control group, an SAL group, a PM_2.5 group, and an SAL+PM_2.5 group, each containing 10 mice. In the SAL group and the SAL+PM_2.5 group, the mice were administered SAL (60 mg·kg⁻¹) by gavage, while in the control group and the PM_2.5 group, sterile saline (10 mL·kg⁻¹) was administered by gavage. In the PM_2.5 group and the SAL+PM_2.5 group, PM_2.5 suspension (8 mg·kg⁻¹) was intratracheally instilled, and in the control group and SAL group, sterile saline (1.5 mL·kg⁻¹) was intratracheally administered. Each experiment cycle spanned 2 d, with a total of 10 cycles conducted over 20 d. Histopathological changes in the ileum tissue of the mice were observed after HE staining. Colon contents were collected for gut microbiota sequencing and short-chain fatty acids (SCFAs) measurements. Results The PM_2.5 group showed infiltration of inflammatory cells in the ileum tissue, while the SAL+PM_2.5 group exhibited only a small amount of inflammatory cell infiltration. Compared to the control group, the PM_2.5 group showed decreased Shannon index (P<0.05) and increased Simpson index (P<0.05), indicating that the diversity of gut microbiota in this group was decreased; the SAL+PM_2.5 group showed increased Shannon index compared to the PM_2.5 group (P<0.05) and decreased Simpson index (P<0.05), indicating that the diversity of gut microbiota in mice intervened with SAL was increased. The principal coordinates analysis (PCoA) revealed a significant separation between the PM_2.5 group and the control group, while the separation trend was less evident among the control group, the SAL group, and the SAL+PM_2.5 group. The unweighted pair-group method with arithmetic means (UPGMA) clustering tree results showed that the control group and the SAL group clustered together first, followed by clustering with the SAL+PM_2.5 group, and finally, the three groups clustered with the PM_2.5 group. The PCoA and UPGMA clustering results indicated that the uniformity and similarity of the microbiota in the PM_2.5 group were significantly decreased. Compared to the control group, the PM_2.5 group showed decreased abundance of phylum Bacteroidetes and Candidatus_Saccharimonas (P<0.05) and increased abundance of phylum Proteobacteria, genus Escherichia, genus Bacteroides, genus Prevotella, genus Enterococcus, and genus Proteus (P<0.05). Compared to the PM_2.5 group, the SAL+PM_2.5 group showed decreased abundance of phylum Proteobacteria, phylum Actinobacteria, genus Prevotella, and genus Proteus (P<0.05), and increased abundance of Candidatus_Saccharimonas (P<0.05). The PM_2.5 group showed reduced levels of propionic acid, valeric acid, and hexanoic acid compared to the control group (P<0.05), while the SAL+PM_2.5 group showed increased levels of propionic acid, isobutyric acid, butyric acid, valeric acid, and hexanoic acid compared to the PM_2.5 group (P<0.05). Conclusion Exposure to PM_2.5 can cause pathological alterations, microbial dysbiosis, and disturbing production of SCFAs in intestinal tissue in mice. However, SAL can provide a certain degree of protective effect against these changes.

Background Hexavalent chromium [Cr(VI)] exposure can cause structural disruption of intestinal flora and functional impairment. Vitamin C (VC) is one of the essential micronutrients, which plays an important role in promoting the growth of intestinal probiotics, improving the intestinal barrier, and maintaining the homeostasis of intestinal flora. However, the regulatory effect of VC on the intestinal flora disorders caused by Cr(VI) exposure remains to be investigated. Objective To investigate the effect of VC on intestinal flora disruption in mice due to Cr(VI) exposure. Methods Thirty-two SPF-grade C57BL/6 mice were acclimatized and fed for 3 d and randomly divided into control (Con), VC, potassium dichromate [K₂Cr₂O₇, Cr(VI)], and VC+K₂Cr₂O₇ [VC+Cr(VI)] groups. At 8:00 a.m. on day 4, the Con group (double-distilled water given by gavage and injected intraperitoneally), the VC group (VC given by gavage and double-distilled water injected intraperitoneally), the Cr(VI) group (double-distilled water given by gavage and K₂Cr₂O₇ solution injected intraperitoneally), and the VC+Cr(VI) group (VC given by gavage and K₂Cr₂O₇ solution injected intraperitoneally) were treated. The dose of VC was 200 mg·kg⁻¹, and the dose of K₂Cr₂O₇ was 1.25 mg·kg⁻¹. The mice were treated for 45 consecutive days and then executed, the contents of the colon were sampled in sterile freezing tubes, and three replicates were collected from each group. After labeling, the samples were immediately put into liquid nitrogen for rapid freezing. After all the samples were collected, they were transferred to a -80 ℃ ultra-low temperature refrigerator for storage. Samples of colon contents were analyzed for intestinal flora structure by high-throughput sequencing and bioinformatics software. Results The Cr(VI) exposure resulted in reduced body weight gain values in mice compared to the Con group. Pathological changes occurred in the ileal tissue of mice, with significant inflammatory cell infiltration in the Cr(VI) group and reduced inflammatory cell infiltration in the VC+Cr(VI) group. The number of operational taxonomic units (OTUs) of intestinal flora was altered in the Cr(VI) group of mice. In the α diversity analysis, the mean Sobs index in the Cr(VI) group was 240.333±67.796, the Chao index was 258.173±64.813, and the Ace index was 259.481±66.891, which were significantly lower than those in the Con group (P<0.05), the PD whole tree index in the Cr(VI) group was 27.863±2.399, which was significantly higher than that in the Con group (P<0.05), and the VC intervention significantly reversed the changes of the above indexes due to Cr(VI) exposure (P<0.05). In the β diversity analysis, the principal coordinates analysis (PCoA) results showed a significant separation between the Cr(VI) group and the Con group, and after the VC intervention, there was a retraction of the separation trend and the difference was reduced. The multi-sample similarity dendrogram results showed that the control and the VC groups clustered together first, then with the VC+Cr(VI) group, and finally with the Cr(VI) group. The abundances of Bacteroidetes, Saccharibacteria, and Tenericutes in the intestine of mice in the Cr(VI) group were decreased, and the abundance of Firmicutes was increased; the abundances of Lactobacillus, Alistipes, Bacteroides, and Ruminiclostridium were also increased. Included among these, Bacteroides showed a significantly higher abundance compared to the control mice (P<0.05). Changes in the abundances of phyla and genera of the above mentioned gut microorganisms were reversed after the VC intervention. Conclusion Cr(VI) exposure can lead to intestinal damage and disorganization of the intestinal flora structure in mice, while VC intervention can ameliorate the above changes to a certain extent and normalize the intestinal flora structure.

Objective:To investigate the association of urinary cadmium levels with peripheral leukocyte classification counts among middle-aged and older adults aged 40 to 89 years in selected areas of China.Methods:The research was based on the survey of the impact of soil quality of agricultural land on human health in typical areas conducted in 2019-2020. A total of 5 600 middle-aged and older adults aged 40 to 89 years were included by using a multi-stage stratified random sampling method. Baseline characteristics of the subjects were collected and physical examinations were performed. Random midstream urine was collected to measure urinary cadmium and urinary creatinine and fasting venous blood was collected to measure the leukocyte count, neutrophil count, lymphocyte count, monocyte count and eosinophil count. The linear mixed effect model was used to analyse the association of urinary cadmium levels with leukocyte classification counts, and the dose-response relationship between them was analyzed by using the restricted cubic spline (RCS) function.Results:The age of the subjects was (63.17±12.02) years; 2 851 (50.91%) were males; and the M ( Q 1, Q 3) of urinary creatinine-corrected urinary cadmium levels was 2.69 (1.52, 4.69) μg/g·creatinine. After adjusting for confounding factors, the results of linear mixed effects model analysis showed that for each 1-unit increase in urinary creatinine-corrected urinary cadmium level, the percentage change [% (95% CI)] of leukocyte count and lymphocyte count was -1.70% (-2.61%, -0.79%) and -1.57% (-2.86%, -0.26%), respectively. RCS function showed a negative linear relationship between urinary creatinine-corrected urinary cadmium levels and leukocyte counts and lymphocyte counts, respectively (all Pnon-linear>0.05). Conclusion:Urinary cadmium levels are negatively associated with leukocyte count and lymphocyte count among middle-aged and older adults aged 40 to 89 years in selected areas of China.

Objective:To investigate the association of urinary cadmium levels with peripheral leukocyte classification counts among middle-aged and older adults aged 40 to 89 years in selected areas of China.Methods:The research was based on the survey of the impact of soil quality of agricultural land on human health in typical areas conducted in 2019-2020. A total of 5 600 middle-aged and older adults aged 40 to 89 years were included by using a multi-stage stratified random sampling method. Baseline characteristics of the subjects were collected and physical examinations were performed. Random midstream urine was collected to measure urinary cadmium and urinary creatinine and fasting venous blood was collected to measure the leukocyte count, neutrophil count, lymphocyte count, monocyte count and eosinophil count. The linear mixed effect model was used to analyse the association of urinary cadmium levels with leukocyte classification counts, and the dose-response relationship between them was analyzed by using the restricted cubic spline (RCS) function.Results:The age of the subjects was (63.17±12.02) years; 2 851 (50.91%) were males; and the M ( Q 1, Q 3) of urinary creatinine-corrected urinary cadmium levels was 2.69 (1.52, 4.69) μg/g·creatinine. After adjusting for confounding factors, the results of linear mixed effects model analysis showed that for each 1-unit increase in urinary creatinine-corrected urinary cadmium level, the percentage change [% (95% CI)] of leukocyte count and lymphocyte count was -1.70% (-2.61%, -0.79%) and -1.57% (-2.86%, -0.26%), respectively. RCS function showed a negative linear relationship between urinary creatinine-corrected urinary cadmium levels and leukocyte counts and lymphocyte counts, respectively (all Pnon-linear>0.05). Conclusion:Urinary cadmium levels are negatively associated with leukocyte count and lymphocyte count among middle-aged and older adults aged 40 to 89 years in selected areas of China.

Objective: To explore the effect of ambient fine particulate matters (PM_2.5) exposure on nasal oxidative stress level in patients with allergic rhinitis (AR). Methods: A panel of sixty AR patients was recruited as subjects. Four repeated measurements were carried out from June 2017 to January 2018. Nasal irrigation solution was collected and examined for malondialdehyde (MDA) and superoxide dismutase (SOD). Monitoring data of atmospheric pollutants and meteorological factors during measurement periods were also collected. Time activity pattern combined with micro-environment monitoring method was used to evaluate PM_2.5 exposure. Mixed effect model was applied to analyze the relationship between PM_2.5 exposure concentration and oxidative stress level. Results: 49 subjects accomplished the four repeated measurements, and the mean±SD of their age was (36.7±8.4) years old. The median of MDA and SOD in four measurement periods was 3.70, 3.70, 5.58, 6.24 nmol/ml, and 105.50, 102.50, 95.00, 96.50 U/ml. The concentration of PM_2.5 exposure in four measurement periods was (40.0±2.7), (41.5±2.5), (52.3±5.9) and (74.7±4.9) μg/m³, respectively. Results of single pollutant mixed effect model analysis showed that 0-, 1-, 2-, 3-day lag concentrations of PM_2.5 was significantly positively associated with MDA, about β (95%CI) estimated as 0.24 (0.17, 0.30), 0.34 (0.27, 0.41), 0.32 (0.20, 0.44) and 0.33 (0.23, 0.43), respectively. 0-, 1-, 2-day concentrations of PM_2.5 was significantly negatively associated with SOD, about β (95%CI) estimated as -0.99 (-1.66, -0.31), -1.35 (-2.08, -0.62) and -0.94 (-1.80, -0.07), respectively. Multivariate analysis found that lag 1-day concentration of PM_2.5 was still significantly associated with MDA and SOD after controlling for temperature, age and other influencing factors. For a 10 μg/m³ increase of PM_2.5 concentration, MDA increased 0.26 (95%CI: 0.18, 0.33) nmol/ml, and SOD decreased 0.87 (95%CI: 0.21, 1.53) U/ml. Conclusion Our results suggested that PM_2.5 exposure can aggravate the nasal oxidative stress response of AR patients.

Objective: To compare diary-reported trips and Global Positioning System (GPS) recording trips and identify the reasons for the discrepancies between two methods. Methods: The survey was conducted in Jiangning district in Nanjing city during July to September and November to December, 2015. Both the diary records and GPS method were used to investigate the travel behavior of 33 retired adults for 5 consecutive days. The GPS traces were display in Google Earth and then split into trips to compare with the diary records according to time and location. χ² test was used to analyze the influence of trip characteristics on misreporting rates of each method. Results: A total of 1 087 trips in the survey can be compared between the diary (n=909) and the GPS method (n=912). 7.3% (79/1 087) of the trips were only recorded by GPS method, and 11.8% (128/1 087) were only reported in the diary. Of the remaining 880 trips recorded by the both methods, 86.7% (763/880) matched each other, while 13.3% (117/880) did not. For the matched trips, the difference between the trip durations recorded by diary and GPS method was 2.0 (quartile was 6.0) minutes and the diary method overestimated about 25.0% trip durations when compared with the GPS method. The accuracy rates were 84.8%(903/1 065) and 86.9%(925/1 065) for diary and GPS method, respectively. Both methods were more likely to misreport the trip under 5 minutes. The misreporting rates of diary method for trips under 5 minutes were 6.8 times higher than trips over 30 minutes (21.7% vs 3.2%). The reporting accuracy was also significantly different among trips by different travel mode (P<0.05) for both methods, diary method had the lowest accuracy in reporting vehicles recorders (69.3%, 133/192), while GPS method was more accuracy in both biking (91.9%, 136/148) and vehicles recorders(89.6%, 172/192). The main reasons for misreporting by diary method were forgetting or unwilling to record and failing to record trips according to travel mode, while forgetting to carry GPS device, bad GPS signal and failing to locate the position were the main reasons for misreporting by GPS method. Conclusion The majority of the trips reported in diary and GPS method are well consistent with each other. Both of the methods should be used simultaneously in the survey of time-activity pattern to improve the data quality.

Time activity pattern refers to the time and behavior of people at different locations. The knowledge of time-activity pattern is essential for air pollution exposure assessment when direct personal exposure monitoring can't not be conducted, because air pollutant concentrations may vary significantly by location and activity. This review is focused on the survey method for human time-activity pattern and its application in the exposure assessment of air pollutants. After comparing the diary-reported trips and Global Positioning System (GPS) recording method, we believed that diary-reported trips were more reliable in describing comprehensive and detail records of the behavior and environmental circumstances while GPS-recorded trend to maintain sound information of time, location and transportations. Meanwhile, according to different subjects, the air pollution exposure model could be divided for population and individuals. There were great difference between two types of model in many areas, including the required information about time, activity and microenvironment.

Objective A case control study was designed to explore the risk factors of asthma for city children residing for more than half a year,in China.Methods All physician-diagnosed asthma children enrolled in the 3rd nationwide survey (2010) in 43 typical cities of China were selected as the cases,and non-asthmatic children in the same survey were selected as control subjects if they wcre matched with the cases in age and sex.A revised questionnaire on the basis of ISAAC Phase Three Environmental Questionnaire was designed to investigate the risks of asthma among city children aged 0-14 years in China.Chi square analysis and generalized linear mixed models were performed to check the exposure difference between the cases and the controls.Results 43 out of the 44 city centers were qualified according to the results after reviewing both data from the survey and management.As a result,26 950 subjects including 12 450 asthmatic children and 14 500 control subjects were enrolled in the case-control study.Except for the children of Han ethnicity,another 5 980 children (22.2％) of ethnic minorities and 3 1 children (0.1 ％) born in foreign countries were also included as the study subjects.After controlling for city centers as random effect,age,sex,race,problems related to allergy,family history of asthma or allergy,personal medication history of antibiotics,preterm delivery,under caesarean section,baby age for introducing protein-contained foods,environmental tobacco smoking,maternal occupation,indoor plantings,room decorations,dampness,and cooking fuel were proved to be risk factors of childhood asthma.Some differences were seen in the risks of asthma between new cases and current cases.The risk for exposure to indoor plants was different between new cases (OR=2.09,95％CI:1.30-3.36) and current cases (OR=0.80,95％ CI:0.74-0.86).Risks on asthma were varied by age.Allergy,inflection,odor,and preterm delivery (OR=1.72,95％CI:1.42-2.08) appeared to be the key risks for asthma in children younger than 3 years.Apart from the risks,specifically for children younger than 3 years,the risks on asthma for children of 3 to 5 years would also include factors as:sex (OR=1.18,95％CI:1.03-1.35),low birth weight (OR=1.69,95％ CI:1.17-2.44),and caesarean section (OR=1.26,95％ CI:1.10-2.45).Apart from risks specifically for children younger than 6 years,age (OR=0.97,95％CI:0.95-0.99),race (OR=1.61,95％CI:1.26-2.06),and emigration (OR=1.68,95％CI:1.39-2.03) were proved to be associated with asthma for children aged 6-14 years.Conclusion Asthma risks for city children in China would include genetic factors,allergy,infection,and other environmental factors but called for further research in the country.

Objective To explore polycyclic aromatic hydrocarbons(PAHs) exposure of traffic policemen in Beijing and its impact on DNA oxidative damage. Methods From Jun. to Aug. 2007,41 male traffic policemen and 34 male suburban inhabitants in Beijing were selected. The ambient fine particulate matter(PM2.5) was sampled within two consecutive days in the work places of traffic policeman and in the residential area of suburban inhabitants respectively . The levels of urinary 1-hydroxypyrene(1-OHP) and 10 PAHs species were both analyzed by high performance liquid chromatography(HPLC) . The levels of urinary 8-hydroxy-2’-deoxyguanosine(8-OHdG) were detected by ELISA kit,while the questionnaires for health information on smoking,drinking alcohol,exercise habit and so on were also inquired. Results The average levels of PM2.5,benzo[a]pyrene [B(a) P] and total PAHs in the traffic policeman group were 0.096 mg/m3,3.20 ng/m3,and 38.32 ng/m3 respectively,while the corresponding values in the suburban inhabitant group were 0.045 mg/m3,1.54 ng/m3 and 25.43 ng/m3 respectively. The concentration of urinary 1-OHP in the policeman group [(0.50 ?0.38 ) ?mol/mol Cr] was higher than that of the suburban inhabitant group([0.34?0.28) ?mol/mol Cr],P0.05. Multiple factors analysis indicated that urinary 1-OHP and smoking habit had influence on urinary 8-OHdG level,while there was no relationship with other factors(such as drinking alcohol,exercise and cooking habit) . Conclusion Traffic pollution may increase the level of DNA oxidative damage in policemen in Beijing.Traffic and smoking habit-related PAHs exposure is the important influencing factor.

Objective To explore the effect of air pollution on oxidative stress indices(SOD,GSH-Px,MDA) in serum of traffic policemen. Methods From Jun to Aug,2007,sixty-two traffic policemen and thirty-five male suburban inhabitants were selected. The ambient concentrations of PM2.5,polycyclic aromatic hydrocarbons(PAHs) ,nitrogen dioxide,formaldehyde,benzene and toluene were monitored within two consecutive days in the work places of traffic policemen and in the residential areas of suburban inhabitants to assess their air pollution exposure levels. The activity of SOD,GSH-Px and the concentration of MDA in serum were determined with regent kits,while the information on smoking,drinking alcohol,exercising habit and so on was investigated by questionnaire. Results There were significant differences in the concentrations of nitrogen dioxide,formaldehyde,benzene and toluene between the two study groups. The average levels of PM2.5 and PAHs in the traffic policeman group were also higher than those in the control group,but this difference was not significant for small sample size. The activities of SOD and GSH-Px in the traffic policeman group were significantly higher than those in the control group,while the difference of MDA concentration between the two groups was not significant. The relationship between air pollution and the activity of SOD and GSH-Px were also significant after controlling the influence of other factors. Conclusion Air pollution can decrease the activity of SOD and GSH-Px in serum of traffic policemen and induce oxidative stress.