ObjectivesTo investigate the prevalence of mycoplasma pneumonia (MP) in the pediatric outpatient department of Shanghai Pudong New District Zhoupu Hospital and its relationship with the concentration of fine particulate matter (PM 2.5) in the air.MethodsPatients with respiratory tract infection, from one month to 15 years old, diagnosed in the pediatric department of Shanghai Pudong New District Zhoupu Hospital from May 2016 to April 2017 were enrolled. Mycoplasma pneumonia antibody was detected by colloidal gold assay, and mycoplasma antibody was detected after 1 week of negative test. PM 2.5 index of the same period was also collected. SAS 9.1.3 software was used for statistical analysis.ResultsA total of 3 862 children were enrolled, of which 947 were positive for MP, with a positive rate of 24.52%. The positive rates of each age group were 10.02% for the one month to one year old group, 23.51% for the 1 to 4 years old group, 31.70% for the 4 to 7 years old group, and 22.81% for the 7 to 15 years old group. The positive rate of each age group had statistically significant difference (χ2=86.120 0, P<0.000 1). The positive rates of spring, summer, autumn, and winter were 25.06%, 20.43%, 19.52 and 33.61%, respectively. The difference was statistically significant (χ2=67.1446, P<0.000 1). Combining the PM 2.5 index in Shanghai Pudong area from May 2016 to April 2017, the positive correlation between PM 2.5 and positive rate of MP was found (r=0.9007, P<0.001).ConclusionsThe positive rate of MP in Shanghai Pudong area is 24.52%, and reach its highest level in the preschool children and in winter. It is positively correlated with the PM 2.5 index as well.
ObjectiveTo study the possbility of using intranasal instillation of fine particulate matter (PM2.5) combined with inhalation of ozone (O3) to establish mouse model of combined pulmonary fibrosis and emphysema (CPFE), and to provide a reference for the establishment of CPFE model.MethodsMale C57/BL6 mice were divided randomly into phosphate buffer saline (PBS) intranasal instillation+air inhalation group, PBS intranasal instillation+O3 inhalation group and PM2.5 intranasal instillation+O3 inhalation group, with 8 mice in each group. The mice were intranasally instilled with PBS or PM2.5 suspension (7.8 mg/kg) followed by air or ozone inhalation 24 hours later, twice a week over 8 weeks. Lung function, bronchoalveolar lavage fluid (BALF) cell counts and classification were detected, the pathological changes of lung tissues in hematoxylin-eosin staining were observed, including inflammation scores and mean linear intercept (Lm). The thickness of collagen deposition in subepithelium was measured in lung tissues in Masson staining, and simultaneously hydroxyproline contents in lung tissues were determined.ResultsCompared to PBS instillation+air inhalation group, inspiratory capacity (IC), total lung capacity (TLC) and chord compliance (Cchord) were increased, FEV25 (the forced expiratory volume at 25 ms)/FVC (forced vital capacity) was decreased, total cell counts in BALF, Lm and lung inflammatory scores were increased, the thickness of the subepithelial collagen layer (SEc/Pbm) or hydroxyproline contents was not changed in PBS instillation +O3 inhalation group; IC was decreased, functional residual capacity (FRC) was increased, TLC was increased, Cchord was decreased, FEV25/FVC and FEV50 (the forced expiratory volume at 50 ms)/FVC were decreased, total cell counts in BALF, Lm, lung inflammatory scores, SEc/Pbm and hydroxyproline contents were increased in PM2.5 instillation+O3 inhalation group. Compared to PBS instillation+O3 inhalation group, IC was decreased, FRC was increased, Cchord was decreased, FEV25/FVC and FEV50/FVC were decreased, total cell counts in BALF, Lm, lung inflammatory scores, SEc/Pbm and hydroxyproline contents were increased in PM2.5 instillation +O3 inhalation group.ConclusionCPFE mouse model can be successfully established by PM2.5 intranasal instillation combined with ozone inhalation for consecutive 8 weeks.
ObjectiveTo investigate the changes of lung function after exposure to fine particulate matter (PM2.5) for 60 days and the expression of miR-146 in mice.MethodsThirty SPF BALB/c mice were treated with noninvasive tracheal instillation of fine particulate matter suspension at different doses (2.5 mg/kg, 5.0 mg/kg, 10.0 mg/kg) for 2 months (two times one week), the blank group and normal saline group were set as control groups. The mice were examined and killed on the next day after the last instillation. Histopathological changes of the lungs, pro-infammatory factors levels in the lung tissues, pulmonary functions and the relative expression of miR-146a and miR-146b in the lung tissues were detected.ResultsPeak inspiratory flow (PIF) and peak expiratory flow (PEF) were decreased significantly after PM2.5 exposure, however, lung resistance increased and maximal voluntary ventilation reduced from the general tendency without significant difference. Hematoxylin-eosin stain showed lymphocyte infiltration and macrophage infiltration by phagocytic particles, alveolar spacer widening, inflammatory response increased with the increase of PM2.5 exposure dosage. Pro-infammatory factors as interleukin-6 in the bronchoalveolar lavage fluid, interferon-γ and tumor necrosis factor-α in the lung homogenate were increased significantly by enzyme linked immunosorbent assay. The relative expressions of miR-146a and miR-146b were up-regulated remarkablely in treatment groups compared to the control group by real-time fluorescence quantitative polymerase chain reaction, which had negative relationships with PIF and PEF.ConclusionsThe lung function of mice decreases significantly after exposure to fine particulate matter, and the expression of miR-146 is up-regulated.