Role of intestinal flora and 5-HT in depression- and anxiety-like behaviors in mice exposed to PM2.5 / 环境与职业医学

Background Some studies have shown that PM2.5 exposure is closely related to central nervous system diseases that lead to cognitive dysfunction and change the composition of intestinal flora. However, there are few studies on the role of intestinal flora in PM2.5-induced depression- and anxiety-like behaviors in mice. Objective To observe the effects of PM2.5 exposure on depression- and anxiety-like behaviors and the composition of intestinal flora in mice, and to explore the role of intestinal flora in regulating 5-hydroxytryptamine (5-HT) in depression- and anxiety-like behaviors in mice exposed to PM2.5. Methods Eight-week-old male SPF C57BL/6J mice were randomly divided into control group (NS group), probiotic group (LGG group), PM2.5 group (PM group), and combined exposure group (PML group), 6 mice in each group. Mice in the PM group and the PML group were exposed to PM2.5 in a dynamic exposure cabinet for 6 h per day, 6 d a week for 7 consecutive weeks, and the PM2.5 concentrations were approximately 8 times higher than the outdoor concentration. The LGG group and the PML group were orally administered with Lactobacillus rhamnosus while the NS group and the PM group were orally administered with the same amount of saline. Elevated plus maze test and open field test were used to detect depression and anxiety in mice. Fecal samples of mice were collected to evaluate intestinal flora abundance, diversity, and structure between groups using high-throughput sequencing of 16S rRNA. ELISA was employed to detect the levels of 5-HT in serum and hippocampus. Spearman correlation was used to analyze the correlations of differential intestinal flora with 5-HT level in hippocampus and depression- and anxiety-like behavior indicators in mice. Results The percentage of open-arm entry [M(P25, P75)] in the PM group was 0.0% (0.0%, 33.3%), lower than those in the NS group [47.7% (25.0%, 50.8%) ] and the PML group [46.9% (40.0%, 50.0%)], and the differences were statistically significant (P<0.05). The total travelled distance and the time spent in central area (\begin{document}$\bar x \pm s $\end{document}) in the PM group were (2.01±0.90) m and (10.31±1.99) s respectively, shorter than those of the NS group [(3.80±0.89) m, (14.47±3.07) s], the total travelled distance in the PML group [(2.73±1.12) m] was shorter than those of the NS group and the LGG group [(4.21±1.08) m], and the differences were statistically significant (P<0.05). Compared to the NS group, the Simpson index of the PM group significantly increased (P<0.05). Compared to the LGG group, the Simpson index of the PML group significantly decreased (P<0.05). The results of Beta diversity analysis showed that there were differences in the composition of intestinal flora among the four groups of mice. Compared with the NS group and the LGG group, the abundances of Erysipelotrichaceae and Dubosiella in the PM group and the PML group increased, while the abundances of Prevotellaceae_UCG-001 decreased, and the differences were statistically significant (P<0.05). In hippocampus, the level of 5-HT in the PM group [(135.02±10.31) μg·g−1] was lower than those in the NS group [(178.77±43.15) μg·g−1] and the LGG group [(224.85±22.98) μg·g−1], and the level of 5-HT in the PML group [(161.27±15.81) μg·g−1] was lower than that in the LGG group (P<0.05). 5-HT level in hippocampus was significantly positively correlated with the relative abundance of Prevotellaceae_UCG-001 (r=0.6090, P=0.012). The percentage of open-arm entry was significantly negatively correlated with the relative abundance of Dubosiella (r=−0.4630, P=0.023). Conclusion Atmospheric PM2.5 exposure may cause depression- and anxiety-like behaviors in mice. The observed behavior dysfunction may be associated with the changes in diversity and relative abundance of intestinal flora as well as the decrease of 5-HT level. Such depression- and anxiety-like behaviors are alleviated after adding probiotics.

Investigation on psychological stress of mine emergency rescue personnel / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate psychological stress and influence factors on the mine emergency rescue personnel.</p><p><b>METHOD</b>564 mine emergency rescue personnel from a rescue group were select as subjects, and 60 designers from a steel design institute were as controls. Self-made questionnaire and general job stress questionnaire were used to investigate the basic information, rescue history, psychosomatic symptoms, depression symptoms, daily job stress and negative emotions of emergency rescue personnel. SPSS17.0 software was used to analysis the psychological stress on the mine rescue personnel and its influence factors.</p><p><b>RESULTS</b>The detection rate (41.94%) of depression symptoms in rescue team was higher than that of controls (24.90%). The score of daily job stress was higher than that of logistical support. The older age group with higher negative emotional and daily job stress than the younger. The highest negative emotion was in age group of more than 40 years old. The highest score of daily job stress was in ≤30 years old. The score of depression and psychosomatic symptoms were higher than those of the college and the above. The scores of depression in group of duration of rescue <10 years was higher than that of duration≥10 years. The score of daily job stress is the lowest in rescue for 1 to 2 times per year and the highest in group of simulation training once a week. The score of daily job stress and depressive symptoms were getting higher with the extension of combat duty time. Age, hours of combat duty, training times a week, education and life events were the main affecting fectors on mental health of mine rescuers.</p><p><b>CONCLUSIONS</b>Mine rescuers have more psychological stress than generic population. The psychological stress of the mine crew is related to age, education, life events, training and combat readiness duty time.</p>

Effects of lead exposure on copper and copper transporters in choroid plexus of rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of lead exposure on the copper concentration in the brain and serum and the expression of copper transporters in the choroid plexus among rats.</p><p><b>METHODS</b>Sixty specific pathogen-free Sprague-Dawley rats were randomly divided into a control group and three lead-exposed groups, with 8 mice in each group. The lead-exposed groups were orally administrated with 500 (low-dose group)), 1 000 (middle-dose group), and 2 000 mg/L (high-dose group) lead acetate in drinking water for eight weeks. And the rats in control group were given 2 000 mg/L sodium acetate in drinking water. The content of lead and copper in the serum, hippocampus, cortex, choroid plexus, bones, and cerebrospinal fluid (CSF) was determined by inductively coupled plasma-mass spectrometry (ICP-MS). Confocal and real-time PCR methods were applied to measure the expression of copper transporters including copper transporter 1 (Ctr1), antioxidant protein 1 (ATX1), and Cu ATPase (ATP7A).</p><p><b>RESULTS</b>Compared with the control group, the lead-exposed groups showed significantly higher lead concentrations in the serum, cortex, hippocampus, choroid plexus, CSF, and bones (P < 0.05) and significantly higher copper concentrations in the CSF, choroid plexus, serum, and hippocampus (P < 0.05). Confocal images showed that Ctr1 protein was expressed in the cytoplasm and cell membrane of choroid plexus in control group. However, Ctr1 migrated to CSF surface microvilli after lead exposure. Ctr1 fluorescence intensity gradually increased with increasing dose of lead, except that the middle-dose group had a higher Ctr1 fluorescence intensity than the high-dose group. In addition, the middle- and high-dose groups showed a lower ATX1 fluorescence intensity compared with the control group. Real-time PCR data indicated that the three lead-exposed groups showed significantly higher mRNA levels of Ctr1 and ATP7A compared with the control group (P < 0.05).</p><p><b>CONCLUSION</b>Copper homeostasis in the choroid plexus is affected by lead exposure to induce copper homeostasis disorders in brain tissue, which may be one of the mechanisms of lead neurotoxicity.</p>

Study on Effect of Traffic Exhaust Pollution on Saturation of Carboxyhemoglobin in Traffic Policemen / 环境与健康杂志

Objective To study the effect of automobile exhaust pollution saturation of carboxyhemoglobin (COHb) in traffic policemen. Methods 169 traffic policemen working outdoors were selected as a exposure group and 112 traffic policemen working indoors as control group in a traffic policemen detachment in Tangshan. Questionnaires and health examination were conducted in two groups. The carbon monoxide levels in the exhalation were measured in 281 traffic policemen by a micro_smokerlyzer and the corresponding saturation of carboxyhemoglobin (COHb) were read. Results The higher saturation of carboxyhemoglobin were observed in exposure group (2.30%?1.49%) compared with those (1.71%?0.99%) in control group (P