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Background Salidroside (SAL) has a protective effect on multiple organ systems. Exposure to fine particulate matter (PM2.5) 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 PM2.5 requires further investigation. Objective To evaluate gut microbiota disruption in mice after being exposed to PM2.5 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 PM2.5 group, and an SAL+PM2.5 group, each containing 10 mice. In the SAL group and the SAL+PM2.5 group, the mice were administered SAL (60 mg·kg−1) by gavage, while in the control group and the PM2.5 group, sterile saline (10 mL·kg−1) was administered by gavage. In the PM2.5 group and the SAL+PM2.5 group, PM2.5 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 PM2.5 group showed infiltration of inflammatory cells in the ileum tissue, while the SAL+PM2.5 group exhibited only a small amount of inflammatory cell infiltration. Compared to the control group, the PM2.5 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+PM2.5 group showed increased Shannon index compared to the PM2.5 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 PM2.5 group and the control group, while the separation trend was less evident among the control group, the SAL group, and the SAL+PM2.5 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+PM2.5 group, and finally, the three groups clustered with the PM2.5 group. The PCoA and UPGMA clustering results indicated that the uniformity and similarity of the microbiota in the PM2.5 group were significantly decreased. Compared to the control group, the PM2.5 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 PM2.5 group, the SAL+PM2.5 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 PM2.5 group showed reduced levels of propionic acid, valeric acid, and hexanoic acid compared to the control group (P<0.05), while the SAL+PM2.5 group showed increased levels of propionic acid, isobutyric acid, butyric acid, valeric acid, and hexanoic acid compared to the PM2.5 group (P<0.05). Conclusion Exposure to PM2.5 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.
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Background Acute exposure to mercury chloride (HgCl2) can cause liver damage. Whether oleanolic acid (OA) as a hepatoprotective drug can protect against liver injury induced by acute exposure to HgCl2 and related mechanism of action remain unclear. Objective To investigate the protective effect and possible mechanism of OA on liver injury in mice caused by acute exposure to HgCl2. Methods Forty SPF C57BL/6 male mice were randomly divided into four groups with 10 mice in each group according to body weight. The four groups were named control group, OA group (300 mg·kg−1), HgCl2 group (5 mg·kg−1), and OA + HgCl2 group (300 mg·kg−1 OA + 5mg·kg−1 Hgcl2). Soybean oil and OA solution were administered intragastric once a day for two consecutive days. HgCl2 solution was injected intraperitoneally 2 h after the second intragastric administration. Mice were sacrificed after 48 h, and their serum and liver were collected. Liver coefficient was calculated. The changes of liver structure and iron deposition were observed by hematoxylin-eosin (HE) staining and Prussian blue staining. Alanine aminotransferase (ALT), aspartate aminotransferase (AST), total superoxide dismutase (T-SOD), reduced glutathione (GSH), malondialdehyde (MDA), and tissue iron content were measured with commercial kits. Western blotting was used to detect nuclear factor erythroid-2 related factor 2 (Nrf2), heme oxygenase 1 (HO-1), glutathione peroxidase 4 (Gpx4), transferrin receptor 1 (TFR1,) and solute carrier family 7 member 11 (SLC7A11). Results The AST and ALT levels of the HgCl2 group were (76.447±9.695) U·g−1 and (98.563±24.673)U·g−1, respectively, which were higher than those of the control group (P<0.05). After the OA pretreatment, the liver coefficient and the above indexes were decreased to (4.769±0.237)%, (57.086±10.087) U·g−1, and (87.294±27.181)U·g−1, respectively. The liver coefficient and AST level of the OA + HgCl2 group were significantly different from those of the HgCl2 group (P<0.05). After acute exposure to HgCl2, the hepatocytes of mice were disordered, accompanied by inflammatory infiltration, positive blue particles appeared in Prussian blue staining of liver tissue, and the above changes in liver tissue were alleviated after the OA pretreatment. The iron content in the HgCl2 group was (3.646±0.238) μmol·g−1, which was higher than that in the control group, (2.948±0.308) μmol·g−1. After the OA pretreatment, the iron content decreased to (3.429±0.415) μmol·g−1. Compared with the control group, acute exposure to HgCl2 resulted in decreased levels of GSH and T-SOD, decreased protein expression levels of Nrf2, HO-1, SLC7A11, and Gpx4, increased level of MDA, and increased protein expression level of TFR1 (P<0.05). After the OA pretreatment, all indicators were improved including increased GSH level, decreased MDA level, increased Nrf2, HO-1, and SLC7A11 protein expression levels, and decreased TFR1 protein expression level; compared with the HgCl2 group, the differences were statistically significant (P<0.05). Conclusion Acute HgCl2 exposure could induce liver injury in mice, and its mechanism may involve iron overload and ferroptosis. OA may alleviate the liver injury caused by acute HgCl2 exposure by affecting iron overload and the ferroptosis-related protein expression.
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OBJECTIVE: To understand the relationship between radon exposure and oxidative damage in solar greenhouse employees.METHODS: A total of 216 solar greenhouse employees were selected as the study subjects by using cluster random sampling method.Radon concentrations in solar greenhouses were detected by using continuous radon measuring instrument,which were used to estimate the annual radon radiation dose in solar greenhouse employees.T-superoxide dismutase( T-SOD) and malondialdehyde( MDA) levels in venous blood were measured,which were used to present the oxidative damage effects in solar greenhouse employees.RESULTS: The annual radon radiation dose of solar greenhouse employees was 2.00 mSv in 2014.T-SOD activity was( 87.43 ± 15.77) × 10~3 U/L,and MDA concentration was( 4.36 ±0.62) μmol/L.Multivariate logistic regression analysis results showed that after excluding confounding factors such as gender,age,smoking,alcohol drinking,planting length and pesticide exposure score,the higher the radon exposure dose,the higher risk of abnormalities in T-SOD activity and MDA concentration( P < 0.05).CONCLUSION: There is a correlation between radon exposure and oxidative damage effects in solar greenhouse employees.
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Objective To explore the effects of temperature and relative humidity on radon exhalation rate of glazed tile in the hermetic environment. Methods Ordinary glazed tile was used as experimental object to detect radon concentration with Model 1027 continuous radon monitor in a 0.25 m3 simulation chamber at different temperature and humidity,and then calculated the radon exhalation rate. Results In reasonable range,a cubic correlation between radon exhalation rate(ER) and relative humidity(RH) expressed as ER=0.000 2RH3-0.040 2RH2+2.623 9RH-32.303(R2=0.986 6)was found; a cubic function relationship between radon exhalation rate(ER) and temperature(t) expressed as ER=-0.022 5t3+2.016 5t2-58.748t+565.05(R2=0.969 8)was also observed. Conclusion Environmental temperature and relative humidity have great effects on radon exhalation rate of glazed tile.
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Much attention have been paid to the researches on radon,radon progeny and volatile organic compounds in the field of indoor air pollution in recent years. The recent researches on indoor radon pollution were reviewed in the present paper,including the sources,influencing factors,health effects and defending measurements.