[The role of autophagy in PM2.5-induced inflammation in human nasal epithelial cells].

Objective: To explore the role of autophagy in PM2.5-induced inflammation in human nasal epithelial cells and related mechanism. Methods: Human nasal epithelial cells were exposed to different concentration of PM2.5 for different times, and the expression levels of microtubule-associated protein-1 light chain-3 Ⅱ (LC3 Ⅱ) and Beclin1 proteins were measured by Western blot. The typical autophagosome and autolysosome were observed by using transmission electron microscopy (TEM). To observe autophagic flux, mRFP-GFP-LC3 plasmid was transfected to nasal epithelial cells and the punctate staining of mRFP-GFP-LC3 were determined by confocal laser scanning microscope. The expression of inflammatory cytokines interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) in cell culture supernatant were assessed by enzyme-linked immunosorbent assay (ELISA). To assess the role of autophagy in PM2.5-mediated inflammation, autophagy related gene Atg5 and Beclin-1 were silenced by siRNA knockdown, and inflammatory cytokines were analyzed.GraphPad Prism 6.0 was used for statistical analysis. Results: PM2.5 exposure increased the expression of LC3 Ⅱ and Beclin-1 proteins in a dose- (in PM2.5 group with concentration of 0, 15, 30, 60, 120 µg/ml, the expression of LC3 Ⅱ was 0.021±0.001(x±s), 0.037±0.002, 0.058±0.005, 0.075±0.006, 0.085±0.004, respectively, F=126.8, P<0.05; the expression of Beclin-1 was 0.002±0.000, 0.003±0.000, 0.005±0.000, 0.007±0.001, 0.008±0.001, respectively, F=137.3, P<0.05) and time-dependent manner (in PM2.5 group with exposure time of 0, 3, 6, 12, 24 h, the expression of LC3Ⅱ was 0.160±0.007, 0.222±0.003, 0.251±0.015, 0.483±0.029, 0.585±0.035, respectively, F=215.3, P<0.05; the expression of Beclin-1 was 0.059±0.002, 0.080±0.002, 0.087±0.002, 0.183±0.007, 0.228±0.005, respectively, F=137.3, P<0.05) in human nasal epithelial cells. TEM analysis showed typical autophagosome and autolysosome in cells after PM2.5 exposure for 24 h. PM2.5 significantly increased the number of yellow and red dots representing autophagosomes and autolysosomes respectively, indicating autophagic flux was elevated. Moreover, PM2.5 enhanced the secretion of inflammatory cytokines such as IL-6 and TNF-α, which was dramatically prevented by Atg5-siRNA and Beclin-1-siRNA. Conclusion: Autophagy plays an important role in PM2.5-caused inflammation response in nasal epithelial cells, which can induce release of inflammatory factors such as IL-6 and TNF-α and advance the inflammatory reaction.

[Effect of PM2.5 on inflammatory factors and pathology of nasal mucosa in a rat model of allergic rhinitis].

Objective: To investigate the effect of PM2.5 exposure on nasal inflammatory cytokines and nasal mucosal pathology in a rat model of allergic rhinitis (AR). Methods: Twenty-four healthy female SD rats were randomly divided into 3 groups by random number table method, with 8 rats in each group: normal control group (NC group), ovalbumin (OVA) induced AR model (AR group), and AR model group inhaled to PM2.5 at 200 µg/m(3), 3 h/d, for 30 d (ARE group). Nasal symptoms including sneezing, nasal rubs and nasal secretion were recorded. Levels of OVA specific IgE in serum, interleukin 6 (IL-6) and tumor necrosis factor-ɑ (TNF-ɑ) in nasal irrigating solution were measured by enzyme-linked immunosorbent assay (ELISA). The histopathological changes of nasal mucosa were observed by HE staining. SPSS 17.0 software was used to analyze the data. Results: The number of sneezing, nasal rubs and the amount of nasal secretion in the ARE group were significantly higher than that in the AR group and the NC group (number of sneezing (15.38±1.68) times/15 min vs (11.63±1.13) times/15 min vs (1.75±0.71) times/15 min, number of nasal rubs (27.75±2.12) times/15 min vs (21.25±2.96) times/15 min vs (5.25±1.04) times/15 min, amount of nasal secretion (18.90±2.07) mg vs (13.83±1.81) mg vs (3.78±0.41) mg, F values was 236.089, 224.139, 183.971, respectively, all P<0.001). Statistically significant differences in OVA specific IgE, IL-6 and TNF-ɑ levels were observed in ARE group exceeded AR group and NC group (OVA specific IgE (25.42±2.51) ng/ml vs (18.07±1.07) ng/ml vs (1.47±0.26) ng/ml, IL-6 (123.30±18.86) pg/ml vs (63.49±11.29) pg/ml vs (16.87±3.29) pg/ml, TNF-ɑ (162.50±38.15) pg/ml vs (72.96±11.28) pg/ml vs (27.52±4.15) pg/ml, F values was 481.604, 138.277, 63.938, respectively, all P<0.001). HE staining showed that the nasal epithelial cells of NC group were intact and neatly arranged. Nasal mucosa epithelial cells were arranged in disorder in AR group, with tissue structure swelling. Partial shedding of nasal epithelial cells, mucosal basement membrane thickening, submucosal tissue interstitial edema, vasodilation and gland hyperplasia were found in ARE group. Conclusion: An increase inflammatory factors level such as IL-6 and TNF-ɑ aggravates pathological damage of nasal mucosa in a rat model of AR by exposure to PM2.5.

[The effect of PM2.5 on mucus secretion and ultrastructureof nasal mucosa in allergic rhinitis model].

Objective:The aim of this study is to the roles of nasal lavage fluid levels of MUC5AC, goblet cell hyperplasia and ultrastructure of nasal mucosa following ambient PM2.5 exposure in a rat model of allergic rhinitis(AR).Method:Female Sprague-Dawley rats were assigned randomly into 3 groups: a negative control group(NC group),an ovalbumin(OVA)-induced AR model group(AR group), and AR model group(ARE group) inhaled to PM2.5 at 200 µg/m³, 3 h/d, for 30 days. Nasal symptoms, levels of MUC5AC in nasal lavage fluid(NLF), were measured in each individual rat.Goblet cell hyperplasia were examined histologically with PAS-stained. Nasal mucosa tissue ultrastructure were observed by scanning electron microscope.Result:PM2.5 significantly increased the number of sneezes, nasal rubs and the amount of nasal secretion in rats with AR.Statistically significant differences in MUC5AC levels and goblet cell hyperplasia were observed between the AR model exposure to PM2.5 and the AR model group.The nasal mucosa of AR model exposure to PM2.5 was disordered,lodged,assembled and twisted.Conclusion:Our data indicate that an increase MUC5AC level in NLF and the development of nasal goblet cell hyperplasia may provide some clues for determining the pathogenic mechanisms of AR by exposure to PM2.5.

Preliminary study of the distribution of the toxic elements As, Cd, and Hg in human hair and tissues by RNAA.

In order to study the relationships between trace element concentrations of hair and internal body burdens, a radiochemical NAA technique has been used for determination of the elements As, Cd, and Hg in autopsy samples of liver, kidney-cortex, lung, and hair from 24 male persons who died by accident. High significant positive correlations were observed between the As concentration in hair and in kidney-cortex, and between Cd and Zn concentrations in kidney-cortex. The contents of Cd, both for lung and kidney-cortex, were related to the smoking habits of the subjects.