Objective:To investigate the effects of ursolic acid (UA) on oxidative stress and inflammatory factors in a rat model of AR after PM2.5 exposure.Methods:Sixty healthy female SD rats were randomly divided into five groups: normal control group (NC group), PM2.5 unexposed AR group (AR group), PM2.5 exposed AR group (ARE group), UA intervention AR group (AR+UA group), and UA intervention PM2.5 exposed AR group (ARE+UA group), with 12 rats in each group. AR model was performed by a basal sensitization with intraperitoneal injection of ovalbumin (OVA) and followed by nasal instillation. PM2.5 exposure was carried out by inhalation exposure system at a concentration of 200 μg/m 3 for 3 h/d for 30 days. UA intervention group was given UA intragastric administration at 20 mg/(kg·d). AR symptoms including sneezing, nasal scratching and nasal secretion of rats in each group were observed. The activities of superoxide dismutase (SOD) and the level of malondialdehyde (MDA) in nasal mucosa were tested. The pathological changes of nasal mucosa were observed by HE staining. The levels of OVA-sIgE, IL-6 and IL-17 in serum were measured by enzyme-linked immunosorbent assay (ELISA). Protein microarray was used to measure the expression of multiple inflammation cell factors in nasal mucosa. Statistical analysis was performed with SPSS 20.0. Results:After UA intervention, the frequency of nasal sneezing, scratching and nasal secretion in ARE+UA group were lower than those of ARE group ( P<0.05). Pathological examination of nasal mucosa showed that ARE+UA group had less inflammatory granulocyte infiltration and less pathological damage to the epithelial layer than ARE group. The activities of SOD in nasal mucosa of ARE+UA group were higher than those of ARE group ((50.10±3.09) U/mg vs (20.13±1.30) U/mg, F value was 597.54, P<0.01). The contents of MDA in nasal mucosa of ARE+UA group were lower than those of ARE group ((57.78±12.36) nmol/g vs (124.12±9.40) nmol/g, F value was 115.51, P<0.01). The expression levels of OVA-sIgE, IL-6 and IL-17 proteins were lower in the ARE+UA group than those in ARE group ((11.61±0.27) ng/ml vs (20.30±0.67) ng/ml, (47.59±15.49) pg/ml vs (98.83±10.98) pg/ml, (623.30±8.75) pg/ml vs (913.32±9.06) pg/ml, F value was 283.42, 80.45, 683.73, respectively, all P<0.01). After UA intervention, protein microarray analysis showed that the expression of IL-4, IL-6, IL-13, chemokine CXCL7, IL-1α, IL-1β, MMP-8 and MCP-1 in ARE+UA group was decreased compared with ARE group while IFN-γ and IL-10 increased (all P<0.01). Conclusion:UA can reduce the aggravated AR symptoms and pathological damage of nasal mucosa, inhibit oxidative stress and release of inflammatory factors after PM2.5 exposure, and thus plays a protective role in the pathological damage of AR induced by PM2.5 exposure.

OBJECTIVETo investigate the effects of different concentrations of lipopolysaccharide (LPS) on proliferation and apoptosis of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro, and to explore their possible mechanism.

METHODShUCMSCs from umbilical cord tissue of full-term healthy fetus delivered by caesarean section were isolated and cultured in vitro using tissue attachment method. The 3rd passage hUCMSCs were used in the study. Cells were divided into groups A, B, C, D, and E, which were treated with DMEM/F12 medium containing 0, 0.1, 1.0, 10.0, and 100.0 µg/mL of LPS respectively. In groups B, C, D, and E, methyl-thiazole-tetrazolium assay was used to detect proliferative activity of hUCMSCs at post treatment hour (PTH) 12, 24, and 48 (denoted as absorption value), with 5 samples in each group at each time point; apoptosis of hUCMSCs at PBH 24 was identified with acridine orange-ethidium bromide (AO-EB) staining, with 4 samples in each group; apoptotic rate of hUCMSCs was determined by flow cytometer, with 5 samples in each group. Above-mentioned indexes were determined in group A at the same time points. Data were processed with analysis of variance and LSD- t test.

RESULTS(1) There was no statistically significant difference in proliferative activity of hUCMSCs at PTH 12 among groups A, B, C, D, and E (with t values from -1.67 to 1.33, P values above 0.05). Compared with that of group A, proliferative activity of hUCMSCs was increased in groups B, C, and D at PTH 24 and 48 (with t values from -13.42 to 17.34, P < 0.05 or P < 0.01), especially so in group C. Proliferative activity of hUCMSCs was lower in group E at PTH 24 and 48 than in group A (with t values respectively 8.64 and 17.34, P values below 0.01). (2) Obvious apoptosis of hUCMSCs was observed in group E but not in the other 4 groups with AO-EB staining. (3) Apoptosis rates of hUCMSCs in groups A, B, C, D, and E were respectively (3.1 ± 0.6)%, (2.6 ± 0.7)%, (2.9 ± 0.8)%, (3.1 ± 0.4)%, (25.1 ± 2.7)% (F = 272.19, P < 0.01). Apoptotic rate of hUCMSCs in group B, C, or D was respectively close to that in group A (with t values respectively 1.22, 0.57, -0.14, P values above 0.05), but it was higher in group E than in group A (t = -17.63, P < 0.01).

CONCLUSIONShUCMSCs proliferation may be promoted by low concentration of LPS. hUCMSCs proliferation is inhibited or induced to apoptosis along with the increase in concentration of LPS, and it may be related to activation of different major molecular signaling pathways by different concentrations of LPS.

Apoptosis ; drug effects ; Cell Proliferation ; Endotoxins ; adverse effects ; Humans ; Lipopolysaccharides ; pharmacology ; Membrane Proteins ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Signal Transduction ; Umbilical Cord ; cytology