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The 27 subjects had an average BMI of 23.1 kg/m2. Among them, 17 (62.96%) were females. All subjects were tested for lung function and fractional exhaled nitric oxide (FeNO). The baseline characteristics of the study subjects are shown in Table 1.
Characteristics Result Age (y) 49.8 ± 16.18 BMI (kg/m2) 23.10 ± 3.18 Female 17 (62.96%) ACT score in baseline 17.14 ± 4.57 *FEV1 (L) 2.18 ± 0.91 **FVC (L) 2.82 ± 1.49 ***FEV1/FVC (%) 79.95 ± 13.91 FeNO (ppb) 48 ± 45 (Min 10, Max 238) Note. *FEV1 Forced vital capacity in 1 second; **FVC forced vital capacity; ***FEV1/FVC Ratio of forced vital capacity in 1 second to forced vital capacity. Table 1. Characteristics and baseline of the study subjects (n = 27)
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We collected the PEF recorded by the peak flow metre and the meteorological data (AQI, air quality evaluation, PM2.5, PM10, O3, NO2, SO2, CO subindex and their daily mean concentrations) on the day of each follow-up and the three days after that of each subject. Spearman correlation analysis was carried out using these data. The PEF value was correlated with the O3 and NO2 subindexes and their daily mean values (O3 subindex P = 0.0009, O3 daily mean value P = 0.0012, NO2 subindex P = 0.0155, NO2 daily mean value P = 0.0215) (Table 2). Further multiple regression analysis of several meteorological indexes related to PEF found that when other factors remained unchanged, the PEF value decreased by 0.44 mL/min for every 1 μg/m3 increase in the daily mean value of O3 and by 2.02 mL/min for every 1 unit increase in the NO2 subindex (Table 2).
Ambient air pollutants PEF PM2.5 sub index P = 0.2270 PM10 sub index P = 0.3457 O3 sub index P = 0.0009* SO2 sub index P = 0.3585 NO2 sub index P = 0.0155* CO sub index P = 0.1223 AQI P = 0.7173 PM2.5 day average (μg/m3) P = 0.3480 PM10 day average (μg/m3) P = 0.2054 O3 daily maximum 8-hour mean (μg/m3) P = 0.0012* SO2 day average (μg/m3) P = 0.4499 NO2 day average (μg/m3) P = 0.0215* CO day average (μg/m3) P = 0.2347 Note. *P < 0.05. PEF, peak expiratory flow. Table 2. Acute effect of Ambient air pollutants on patients with asthma
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The chronic effect had 6 months as the time interval. The mean value of each index of each component in ambient air pollutants during this period was compared with the patient’s pulmonary function, inflammatory index, ACT symptom score and FeNO by Spearman correlation analysis. There was no correlation between the pulmonary function index, ACT symptom score, FeNO and ambient air pollutants in patients with asthma (Table 3). However, IL-5 and IL-13 concentrations were correlated with some ambient air pollutants. IL-5 was correlated with the AQI, PM2.5 index, PM10 index, PM2.5 daily average concentration and PM10 daily average concentration. IL-13 was correlated with the PM2.5 index, PM10 index and their daily average concentration (P < 0.05) (Table 4). Multiple regression analysis of individual inflammation indexes on several meteorological indexes related to inflammation index found that when other factors remained unchanged, IL-5 increased by 2.25 pg/mL for every 1-unit increase in the PM2.5 index and increased by 2.06 pg/mL for every 1-unit increase in the PM10 index.
Ambient air pollutants FEV1 FeNO ACT PM2.5 sub index P = 0.6036 P = 0.4658 P = 0.5521 PM10 sub index P = 0.4194 P = 0.9978 P = 0.5440 O3 sub index P = 0.5153 P = 0.1185 P = 0.3486 SO2 sub index P = 0.4600 P = 0.1548 P = 0.1848 NO2 sub index P = 0.7375 P = 0.2967 P = 0.7345 CO sub index P = 0.8859 P = 0.1502 P = 0.5727 AQI P = 0.8059 P = 0.3967 P = 0.4221 PM2.5 day average (μg/m3) P = 0.4352 P = 0.6364 P = 0.6118 PM10 day average (μg/m3) P = 0.4623 P = 0.9405 P = 0.4724 O3 daily maximum 8-hour mean (μg/m3) P = 0.2652 P = 0.2269 P = 0.2830 SO2 day average (μg/m3) P = 0.3499 P = 0.2165 P = 0.1596 NO2 day average (μg/m3) P = 0.4259 P = 0.4303 P = 0.6470 CO day average (μg/m3) P = 0.5849 P = 0.3686 P = 0.3909 Table 3. Chronic effect of Ambient air pollutants on asthma patients’ symptoms and lung function
Ambient air pollutants IL-4 (pg/mL) IL-5 (pg/mL) IL-13 (pg/mL) PM2.5 sub index P = 0.3565 P = 0.0355* P = 0.0342* PM10 sub index P = 0.3022 P = 0.0323* P = 0.0272* O3 sub index P = 0.9688 P = 0.6440 P = 0.7883 SO2 sub index P = 0.5094 P = 0.1616 P = 0.1499 NO2 sub index P = 0.4865 P = 0.1538 P = 0.5207 CO sub index P = 0.3754 P = 0.0983 P = 0.1330 AQI P = 0.1236 P = 0.0231* P = 0.0719 PM2.5 day average (μg/m3) P = 0.3279 P = 0.0362* P = 0.0275* PM10 day average (μg/m3) P = 0.3459 P = 0.0361* P = 0.0269* O3 daily maximum 8-hour mean (μg/m3) P = 0.8507 P = 0.6926 P = 0.6804 SO2 day average( μg/m3) P = 0.5094 P = 0.1719 P = 0.1168 NO2 day average (μg/m3) P = 0.5874 P = 0.2046 P = 0.4847 CO day average (μg/m3) P = 0.3824 P = 0.0937 P = 0.0969 Note. *P < 0.05. Table 4. Chronic effect of Ambient air pollutants on asthma patients’ cytokine inflammation
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Figure 3 depicts the variations of histopathological lung among each group, containing the H&E (Figure 3). In the OVA-sensitized group, PM2.5 and OVA-sensitized + PM2.5 groups all showed the characteristics of airway remodeling. The thickening of the airway wall and the infiltration of inflammatory cells were significantly higher than those of the normal saline control group. (Figure 3).
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All of the mice were alive at the end of the animal experiment. The degree of lung injury was different in different groups. There was no significant increase in the lung wet-to-dry (W/D) weight ratio in the asthma and PM2.5 alone groups compared with the control group, but the PM2.5 + OVA group W/D ratio increased obviously (Figure 4A). In addition, the number of cells in BALF increased significantly in the PM2.5 + OVA group compared with the control, asthma and PM2.5 alone groups (Figure 4B).
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Studying the chronic effects of air pollutants on asthma patients, we found that PM2.5 was related to IL-5 and IL-13. Therefore, in the animal experiment, we detected the levels of IL-5 and IL-13 in the blood and bronchial lavage fluid of mice in each group. In blood, we found that the levels of IL-5 in the OVA, PM2.5 and PM2.5 + OVA groups were higher than those in the control group, but the difference only in the OVA model reached a significant level (Figure 5A). In BALF, IL-5 in the PM2. 5 + OVA model was the highest (Figure 5B). In the blood, the changes in IL-13 levels in mice were consistent with those in IL-5 levels. The levels of IL-13 in the asthma, PM2.5 and PM2.5 + OVA groups were higher than those in the control group, but the difference only in the asthma model reached a significant level (Figure 5C). In BALF, the IL-13 levels in the asthma, PM2.5 and PM2.5 + OVA groups were higher than those in the control group. The increase in the PM2.5 and PM2.5 + OVA groups reached statistical significance (Figure 5D).
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In the OVA group, PM2.5 or PM2.5 + OVA group, Penh increased gradually with the extension of time. Penh was higher in the asthma and PM2.5 + OVA groups than in the other two groups. Whether in the OVA group, PM2.5 or PM2.5 + OVA group, Penh was higher than that in the control group on the 15th, 30th, and 40th days (Figure 6A).
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In the OVA-induced asthma mouse group, EF50 increased slowly over time. In the PM2.5 and asthma mouse groups, EF50 changed similarly over time. In the PM2.5 + OVAOVA group, EF50 increased significantly from 30–40 days. In all three experimental groups (asthma, PM2.5, PM2.5 + OVA), EF50 was higher than that in the control group (Figure 6B).
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In vitro, the viability of both HBE and C57 mouse type II alveolar epithelial cells was decreased by 10 µg/mL PM2.5 (Figure 7A). PM2.5 (10 µg/mL) inhibited NF-κB, ERK and p-ERK protein expression in C57 mouse type II alveolar epithelial cells (Figure 7B–C).
Impact of Air Pollutants on Lung Function and Inflammatory Response in Asthma in Shanghai
doi: 10.3967/bes2024.125
- Received Date: 2023-08-12
- Accepted Date: 2024-07-11
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Key words:
- Ambient air pollutants /
- Acute and chronic effects on asthma /
- PM2.5 /
- OVA-induced asthmatic mice
Abstract:
&These authors contributed equally to this work.
Citation: | Guifang Wang, Youzhi Zhang, Haiyan Yang, Yi Yang, Liang Dong, Peng Zhang, Jie Liu, Xiaodong Chen, Yi Gong. Impact of Air Pollutants on Lung Function and Inflammatory Response in Asthma in Shanghai[J]. Biomedical and Environmental Sciences, 2024, 37(8): 811-822. doi: 10.3967/bes2024.125 |