Effects of maternal exposure to arsenic on social behavior and related gene expression in F2 male mice

BACKGROUND@#Arsenic is a developmental neurotoxicant. It means that its neurotoxic effect could occur in offspring by maternal arsenic exposure. Our previous study showed that developmental arsenic exposure impaired social behavior and serotonergic system in C3H adult male mice. These effects might affect the next generation with no direct exposure to arsenic. This study aimed to detect the social behavior and related gene expression changes in F2 male mice born to gestationally arsenite-exposed F1 mice.@*METHODS@#Pregnant C3H/HeN mice (F0) were given free access to tap water (control mice) or tap water containing 85 ppm sodium arsenite from days 8 to 18 of gestation. Arsenite was not given to F1 or F2 mice. The F2 mice were generated by mating among control F1 males and females, and arsenite-F1 males and females at the age of 10 weeks. At 41 weeks and 74 weeks of age respectively, F2 males were used for the assessment of social behavior by a three-chamber social behavior apparatus. Histological features of the prefrontal cortex were studied by ordinary light microscope. Social behavior-related gene expressions were determined in the prefrontal cortex by real time RT-PCR method.@*RESULTS@#The arsenite-F2 male mice showed significantly poor sociability and social novelty preference in both 41-week-old group and 74-week-old group. There was no significant histological difference between the control mice and the arsenite-F2 mice. Regarding gene expression, serotonin receptor 5B (5-HT 5B) mRNA expression was significantly decreased (p < 0.05) in the arsenite-F2 male mice compared to the control F2 male mice in both groups. Brain-derived neurotrophic factor (BDNF) and dopamine receptor D1a (Drd1a) gene expressions were significantly decreased (p < 0.05) only in the arsenite-F2 male mice of the 74-week-old group. Heme oxygenase-1 (HO-1) gene expression was significantly increased (p < 0.001) in the arsenite-F2 male mice of both groups, but plasma 8-hydroxy-2'-deoxyguanosine (8-OHdG) and cyclooxygenase-2 (COX-2) gene expression were not significantly different. Interleukin-1β (IL-1β) mRNA expression was significantly increased only in 41-week-old arsenite-F2 mice.@*CONCLUSIONS@#These findings suggest that maternal arsenic exposure affects social behavior in F2 male mice via serotonergic system in the prefrontal cortex. In this study, COX-2 were not increased although oxidative stress marker (HO-1) was increased significantly in arsnite-F2 male mice.

Effect of COVID-19-restrictive measures on ambient particulate matter pollution in Yangon, Myanmar

BACKGROUND@#Particulate matter (PM) is recognized as the most harmful air pollutant to the human health. The Yangon city indeed suffers much from PM-related air pollution. Recent research has interestingly been focused on the novel subject of changes in the air quality associated with the restrictive measures in place during the current coronavirus disease-2019 (COVID-19) pandemic. The first case of COVID-19 in Myanmar was diagnosed on March 23, 2020. In this article, we report on our attempt to evaluate any effects of the COVID-19-restrictive measures on the ambient PM pollution in Yangon.@*METHODS@#We measured the PM concentrations every second for 1 week on four occasions at three study sites with different characteristics; the first occasion was before the start of the COVID-19 pandemic and the remaining three occasions were while the COVID-19-restrictive measures were in place, including Stay-At-Home and Work-From-Home orders. The Pocket PM@*RESULTS@#The results showed that there was a significant reduction (P < 0.001) in both the PM@*CONCLUSIONS@#We concluded that the restrictive measures which were in effect to combat the COVID-19 pandemic had a positive impact on the ambient PM concentrations. The changes in the PM concentrations are considered to be largely attributable to reduction in anthropogenic emissions as a result of the restrictive measures, although seasonal influences could also have contributed in part. Thus, frequent, once- or twice-weekly Stay-At-Home or Telework campaigns, may be feasible measures to reduce PM-related air pollution. When devising such an action plan, it would be essential to raise the awareness of public about the health risks associated with air pollution and create a social environment in which Telework can be carried out, in order to ensure active compliance by the citizens.

Preliminary monitoring of concentration of particulate matter (PM) in seven townships of Yangon City, Myanmar

BACKGROUND@#Airborne particulate pollution is more critical in the developing world than in the developed countries in which industrialization and urbanization are rapidly increased. Yangon, a second capital of Myanmar, is a highly congested and densely populated city. Yet, there is limited study which assesses particulate matter (PM) in Yangon currently. Few previous local studies were performed to assess particulate air pollution but most results were concerned PM alone using fixed monitoring. Therefore, the present study aimed to assess distribution of PM in different townships of Yangon, Myanmar. This is the first study to quantify the regional distribution of PM in Yangon City.@*METHODS@#The concentration of PM was measured using Pocket PM Sensor (Yaguchi Electric Co., Ltd., Miyagi, Japan) three times (7:00 h, 13:00 h, 19:00 h) for 15 min per day for 5 days from January 25 to 29 in seven townships. Detailed information of eight tracks for PM pollution status in different areas with different conditions within Kamayut Township were also collected.@*RESULTS@#The results showed that in all townships, the highest PM concentrations in the morning followed by the evening and the lowest concentrations in the afternoon were observed. Among the seven townships, Hlaingtharyar Township had the highest concentrations (164 ± 52 μg/m) in the morning and (100 ± 35 μg/m) in the evening. Data from eight tracks in Kamayut Township also indicated that PM concentrations varied between different areas and conditions of the same township at the same time.@*CONCLUSION@#Myanmar is one of the few countries that still have to establish national air quality standards. The results obtained from this study are useful for the better understanding of the nature of air pollution linked to PM. Moreover, the sensor which was used in this study can provide real-time exposure, and this could give more accurate exposure data of the population especially those subpopulations that are highly exposed than fixed station monitoring.