Impacts of Climate Change and Heat Stress on Farmworkers' Health: A Scoping Review

Coenzyme Q10 and vitamin E alleviate heat stress-induced mood disturbances in male mice: Modulation of inflammatory pathways and the HPA axis

Heat stress, as an environmental stressor, can lead to temperature dysregulation and neuroinflammation, causing depression and anxiety by disrupting brain physiology and functional connectivity. This study looked at how co-enzyme Q10 (Q10) and vitamin E (Vit E), alone and together, affected heat stress-caused anxiety and depression symptoms and inflammation in male mice. Five groups were utilized in the study: control, heat stress (NS), Q10, Vit E, and the combination group (Q10+Vit E). The mice were subjected for 15 min/day to a temperature of 43°C for 14 consecutive days, followed by daily treatments for two weeks with either normal saline, Q10 (500 mg/kg), Vit E (250 mg/kg), or their combination. The forced swimming test (FST) and tail suspension test (TST) were employed to evaluate despair behavior, whereas the elevated plus maze (EPM) and open field test (OFT) were used to assess anxious behaviors. Subsequently, the animals were sacrificed, and serum corticosterone levels, protein expression of inflammasome-related proteins, and hsp70 gene expression were evaluated in the prefrontal cortex (PFC). The study revealed that treatment with Vit E and Q10, alone or together, provided anxiolytic and antidepressant effects in the heat-stress-subjected animals. Also, giving Vit E and Q10 alone or together greatly lowered serum corticosterone levels. In the PFC, they also lowered the levels of hsp70 mRNA and NF-κB, caspase 1, NLRP3, and IL-1β proteins. It is speculated that treatment with Q10 and Vit E can attenuate heat stress-associated anxious and depressive responses by inhibiting the inflammatory pathways and modulating the hypothalamus-pituitary-adrenal axis.

Seaweed Farming in Tanzania: A Study of Working Practices and Geospatial Analysis of Occupational Hazards and Adverse Health Outcomes

OBJECTIVE

Work in seafood harvesting and processing has been associated with a range of occupational hazards and associated health problems. However, limited information exists regarding the occupational health risks among workers engaged in seaweed handling.

METHODS

A cross-sectional study was conducted to map seaweed co-operatives (n = 45), assess working practices, and identify common work-related symptoms, occupational hazards, and interventions in seaweed farming sites (n = 24), across three regions of Zanzibar, Tanzania.

RESULTS

Seaweed farming in Zanzibar primarily involves the cultivation of Eucheuma Spinosum, with the majority of workers being women. Common work-related symptoms identified include musculoskeletal symptoms, mainly affecting the wrist (87%), back (84%) and lower limbs (73%). Furthermore, a significant proportion of workers were reported to have skin problems (80%) as well as heat and asthma-related symptoms (51%). Walk-through hazard evaluations of work sites identified a range of occupational hazards, with ergonomic (58-68%), biological (50-63%) and chemical (55-65%) hazards obtaining higher scores across the three regions. Geospatial analysis revealed regional variations in occupational hazards and work-related symptom prevalence, with Unguja South having a statistically significant (p < .05) higher mean prevalence of skin symptoms (95%) and Mjini Magharibi region reporting a higher prevalence of lower limb pain (100%), back pain (100%), and heat-related symptoms (90%). Despite the high hazard scores, interventions were generally lacking across all regions.

CONCLUSION

Occupational health hazards and adverse health outcomes vary across seaweed farming and processing regions. Tailored interventions will be key to improving workplace health and safety of workers engaged in this sector.

The Health and Well-Being of Women in Farming: A Systematic Scoping Review

OBJECTIVES

Health and well-being have long been identified as key issues for investigation within agricultural communities. While myriad studies have been conducted to investigate causation, impact, outcomes and interventions among farming populations, the overall emphasis has been disproportionately weighted away from the experiences of women. This systematic scoping review determines the prevalence of topics, identifies the target populations and geographical locations of studies, outlines methodological approaches to the subject area, and summarizes the key findings and conclusions of the available literature.

METHODS

With the guidance of the Arksey and O'Malley framework for conducting a scoping review, a single database search for publications focusing on the health and well-being of women in farming (including primary farmers, members of farm households, and farmworkers), in the Global North, published between 1990 and 2023, was conducted. Data were organized, thematically coded, critically appraised and analyzed using the systematic review online tool CADIMA.

RESULTS

In total, 93 studies met the inclusion criteria for full review. The majority of studies were conducted in the United States, with the number of publications steadily increasing since the 1990s. Of studies, 68% were wholly quantitative in nature, and 23% wholly qualitative. Key findings suggest women are at particular risk from certain illnesses associated with some aspects of agricultural work and face a number of stressors (including gender-specific issues) that can lower well-being, but evidence is scarce in a number of areas. Clear gaps in research exist in relation to reproductive health, caring responsibilities, or help-seeking and support. Women primary farmer and farmworkers are particularly neglected as study cohorts.

CONCLUSION

Numbers of studies related to the health and well-being of women in farming are still relatively small in comparison with the wider body of related literature, and there exists an obvious need for further studies with a specific emphasis on particular cohorts, issues pertaining to the contemporary climate, and issues specific to women, as well as greater geographical reach. By emphasizing such research gaps, opportunities exist to improve the health and well-being situation of women in agriculture through more explicit studies with the intention of developing more effective, targeted solutions.

Gender Inequities in the Impact of Climate Change on Health: A Scoping Review

In the 21st century, climate change has emerged as a critical global public health challenge. Women experience the most severe impacts of climate change, intensifying pre-existing gender inequalities. This scoping review aims to explore the intersection of climate change, health, and gender, considering the social determinants of health. The methods for this review follow the Arksey and O'Malley framework for a scoping review and the PRISMA-ScR checklist. The review, covering January 2019 to February 2024, included PubMed, LILACS, and SciELO databases. We identified 71 studies with 19 meeting the inclusion criteria. The results revealed the differential effects of climate change on health according to gender in areas such as mental health, reproductive health, gender-based violence, occupational health, and health issues associated with heat and air pollution. Our findings also elucidated how socio-economic and gender inequities intersect, exacerbating the risk of experiencing these effects. In conclusion, the study highlights a clear need for gender-sensitive climate policies and interventions to address these disparities and protect vulnerable populations from the health impacts of climate change.

Climate Change and Health Risk Perceptions of Arkansas Small Farmers through the Application of the Health Belief Model

Climate change poses health risks to Arkansas small farmers. Farmers face an increased risk of heat-related illnesses (e.g., heat exhaustion, cerebral vascular accidents, and cardiovascular issues) and work-related injuries, death, and mental health conditions due to climate change. This cross-sectional survey employed the health belief model (HBM) as its theoretical framework. This study aimed to assess the health status of small farmers, climate change beliefs, adaptive agricultural practices, and the perceived effects of climate change on health. Study data were collected using non-probability sampling methods from small farmers (n = 72) with a gross farm income of < USD 250,000. The study findings show that 93% of participants reported good-excellent health, 69% believe the climate is changing and getting warmer, 58.3% believe people are responsible for the changes in our climate, and 75% believe the changing climate impacts farmers. Among the HBM predictive variables, participants reported self-efficacy (50%), perceived susceptibility (48.6%), and perceived severity (43%). Only 16.7% of farmers reported believing they have all the information needed to prepare for climate-related health impacts. This study suggests small farmers have protective factors and adaptive capacity, including health status, income, and education levels, but believe they lack the information necessary to protect their health from climate change.

Effects of combined treatment with hydrogen-rich electrolyzed water and tea polyphenols on oxidative stress, intestinal injury and intestinal flora disruption in heat-stressed mice

Heat stress (HS) can cause damage to the organism, especially the intestinal tract. In this paper, we investigated the effects of the combined action of tea polyphenols (TP) and hydrogen-rich electrolyzed water (HRW) on HS in mice. The combination of HRW feeding and TP of intraperitoneal injection was screened by in vitro antioxidant activity assay. The results revealed that the combined treatment was more helpful in alleviating the effects of HS on the behavior, growth performance, oxidative damage, and intestinal tract of mice compared with the respective treatments of TP and HRW (P < 0.05). Additionally, the combined treatment could repair HS-induced intestinal dysbiosis in mice, augmenting the number and abundance of bacteria, increasing the number of beneficial genera (Lachnospiraceae_NK4A136_group and Lactobacillus), and decreasing the number of harmful genera (Desulfovibrio and Enterorhabdus), and the effect was significantly better than that of individual treatment (P < 0.05). In conclusion, the combined treatment of TP and HRW effectively mitigates the adverse effects of HS on mouse behavior, growth performance, oxidative damage, and intestinal dysbiosis, surpassing the efficacy of individual treatments with TP or HRW alone.

Legislative review and recommendations for improving sun protection in schools

BACKGROUND

Sun exposure in schools can account for a large portion of childhood sun exposure before the age of 20 years, yet legislation in the United States is lacking to properly protect children. Schools serve as a foundational resource to introduce and implement sun-safe practices in the youth population.

METHODS

Federal and state legislation relating to the access of sunscreen, sun-protective apparel, and shade was reviewed via the website LegiScan.com.

RESULTS

At the time of publication, only 25 states have legislation in place that addresses and allows sunscreen to be used in school, given its classification as an over-the-counter medication. No state has implemented legislation allowing sunglasses to be worn in school, and only two states have laws explicitly allowing hats and other sun-protective apparel at schools. In addition, the provision of shade is addressed in four states.

CONCLUSIONS

With a significant portion of sun exposure occurring at schools, state and federal legislation must address sun protection for students, opening the door for expanded access and additional research related to skin cancer prevention.

Effects of extreme weather on health in underserved communities

Increased fossil fuel use has increased carbon dioxide concentrations leading to global warming and climate change with increased frequency and intensity of extreme weather events such as thunderstorms, wildfires, droughts, and heat waves. These changes increase the risk of adverse health effects for all human beings. However, these experiences do not affect everyone equally. Underserved communities, including people of color, the elderly, people living with chronic conditions, and socioeconomically disadvantaged groups, have greater vulnerability to the impacts of climate change. These vulnerabilities are a result of multiple factors such as disparities in health care, lower educational status, and systemic racism. These social inequities are exacerbated by extreme weather events, which act as threat multipliers increasing disparities in health outcomes. It is clear that without human action, these global temperatures will continue to increase to unbearable levels creating an existential crisis. There is now global consensus that climate change is caused by anthropogenic activity and that actions to mitigate and adapt to climate change are urgently needed. The 2015 Paris Accord was the first truly global commitment that set goals to limit further warming. It also aimed to implement equity in action, founded on the principle of common but differentiated responsibilities. Meeting these goals requires individual, community, organizational, national, and global cooperation. Health care professionals, often in the frontline with firsthand knowledge of the health impacts of climate change, can play a key role in advocating for just and equitable climate change adaptation and mitigation policies.

The impact of heat stress on the human plasma lipidome

The year of 2023 displayed the highest average global temperatures since it has been recorded-the duration and severity of extreme heat are projected to increase. Rising global temperatures represent a major public health threat, especially to occupations exposed to hot environments, such as construction and agricultural workers, and first responders. Despite efforts of the scientific community, there is still a need to characterize the pathophysiological processes leading to heat related illness and develop biomarkers that can predict its onset. Here, we performed a plasma lipidomic analysis on male and female subjects who underwent heat tolerance testing (HTT), consisting of a 2-h treadmill walk at 5 km/h with 2% inclination at a controlled temperature of 40°C. We identified 995 lipids from 27 classes, with nearly half of all detected lipids being responsive to HTT. Lipid classes related to substrate utilization were predominantly affected by HTT, with a downregulation of triacylglycerols and upregulation of free fatty acids and acyl-carnitines (CARs). We additionally examined correlations between changes in plasma lipids by using the physiological strain index (PSI). Here, even chain CAR 4:0, 14:0 and 16:1, suggested by-products of incomplete beta oxidation, and diacylglycerols displayed the highest correlation to PSI. PSI did not correlate with plasma lactate levels, suggesting that correlations between even chain CARs and PSI is related to metabolic efficiency versus physical exertion. Overall, our results show that HTT has a strong impact on the plasma lipidome and that metabolic inefficiencies may underlie heat intolerance.

Application and demonstration of meso-activity exposure factors to advance estimates of incidental soil ingestion among agricultural workers

BACKGROUND

Soil is an understudied and underregulated pathway of chemical exposure, particularly for agricultural workers who cultivate food in soils. Little is known about how agricultural workers spend their time and how they may contact soil while growing food. Exposure factors are behavioral and environmental variables used in exposure estimation.

OBJECTIVES

Our study aimed to derive exposure factors describing how growers engage in different tasks and use those factors to advance the use of time-activity data to estimate soil ingestion exposures among agricultural workers.

METHODS

We administered a meso-activity-based, season-specific soil contact activity questionnaire to 38 fruit and vegetable growers. We asked growers to estimate the frequency and duration of six meso-activities and describe how they completed them. We used questionnaire data to derive exposure factors and estimate empirical and simulated exposures to a hypothetical contaminant in soil via incidental ingestion using daily, hourly, and hourly-task-specific ingestion rates.

RESULTS

We generated exposure factors characterizing the frequency and duration of six meso-activities by season, and self-reported soil contact, glove use, and handwashing practices by meso-activity and season. Seasonal average daily doses (ADDs) were similar across all three forms of ingestion rates. No consistent patterns regarding task-specific contributions to seasonal or annual ADDs were observed.

Barriers and drivers of farmers to provide outdoor access in pig farming systems: a qualitative study

Part of the farmers have chosen to raise pigs with outdoor access. However, providing outdoor access to pigs is not a simple matter, and many farmers are hesitating or feel powerless to engage in this transition. A better understanding of their needs and challenges could facilitate the development of innovations that generate commitment. This survey aimed to identify the French pig farmers' barriers to and drivers for providing outdoor access to pigs. A total of 36 farmers, aged 25-60, who worked in all types of pig farming systems (from full indoor to free-range) participated in a semi-structured interview that lasted 1.25-2.25 h. The topics covered included a historical overview, a description of the farm and practices, as well as opinions about the impact of outdoor access on farmers, animals, production and economic performance, environment, and society. Qualitative data were analysed using thematic analysis. Most of the participants agreed that rearing pigs indoors is a different job from that of rearing pigs with outdoor access and that it is above all a matter of choice, farmer work conception, and work comfort. Farmers generally agreed that working outdoors is particularly arduous, but this could be compensated by the satisfaction of being in contact with nature and seeing animals in a more complex environment. A large majority of farmers managing a system with outdoor access raised the issue of lack of support, highlighting the need for refinement and diffusion of guides of practices as well as day-to-day support. The impact of outdoor access on the health and welfare of pigs was discussed, especially regarding climatic hazards and the risk of zoonoses, and several outdoor farmers explained how their relationship with the animals changes when pigs are raised outside. Given that zootechnical performance may significantly decrease in farms with outdoor access, various strategies can be employed to maintain profitability, such as feed production, circularity, direct sales, or work diversification. They could be either motivating or demotivating factors depending on the individuals. Concerns about social criticism were prominent among many indoor farmers while farmers providing outdoor access generally felt more serene and proud. Overall, this study can serve as a basis to identify levers that could remove barriers, foster the adherence of more farmers, and facilitate the transition towards more pig farming systems with outdoor access, provided that those systems are viable and beneficial for the welfare and health of the animals and farmers.

Exposure to Concurrent Heatwaves and Ozone Pollution and Associations with Mortality Risk: A Nationwide Study in China

BACKGROUND

Concurrent extreme events are projected to occur more frequently under a changing climate. Understanding the mortality risk and burden of the concurrent heatwaves and ozone (O 3 ) pollution may support the formulation of adaptation strategies and early warning systems for concurrent events in the context of climate change.

OBJECTIVES

We aimed to estimate the mortality risk and excess deaths of concurrent heatwaves and O 3 pollution across 250 counties in China.

METHODS

We collected daily mortality, meteorological, and air pollution data for the summer (1 June to 30 September) during 2013-2018. We defined heatwaves and high O 3 pollution days, then we divided the identified days into three categories: a) days with only heatwaves (heatwave-only event), b) days with only high O 3 pollution (high O 3 pollution-only event), and c) days with concurrent heatwaves and high O 3 pollution (concurrent event). A generalized linear model with a quasi-Poisson regression was used to estimate the risk of mortality associated with extreme events for each county. Then we conducted a random-effects meta-analysis to pool the county-specific estimates to derive the overall effect estimates. We used mixed-effects meta-regression to identify the drivers of the heterogeneity. Finally, we estimated the excess death attributable to extreme events (heatwave-only, high O 3 pollution-only, and concurrent events) from 2013 to 2020.

RESULTS

A higher all-cause mortality risk was associated with exposure to the concurrent heatwaves and high O 3 pollution than exposure to a heatwave-only or a high O 3 pollution-only event. The effects of a concurrent event on circulatory and respiratory mortality were higher than all-cause and nonaccidental mortality. Sex and age significantly impacted the association of concurrent events and heatwave-only events with all-cause mortality. We estimated that annual average excess deaths attributed to the concurrent events were 6,249 in China from 2017 to 2020, 5.7 times higher than the annual average excess deaths attributed to the concurrent events from 2013 to 2016. The annual average proportion of excess deaths attributed to the concurrent events in the total excess deaths caused by three types of events (heatwave-only events, high O 3 pollution-only events, and concurrent events) increased significantly in 2017-2020 (31.50%; 95% CI: 26.73%, 35.53%) compared with 2013-2016 (9.65%; 95% CI: 5.67%, 10.81%). Relative excess risk due to interaction revealed positive additive interaction considering the concurrent effect of heatwaves and high O 3 pollution.

DISCUSSION

Our findings may provide scientific basis for establishing a concurrent event early warning system to reduce the adverse health impact of the concurrent heatwaves and high O 3 pollution. https://doi.org/10.1289/EHP13790.

Fruit ripening under heat stress: The intriguing role of ethylene-mediated signaling

Crop production is significantly influenced by climate, and even minor climate changes can have a substantial impact on crop yields. Rising temperature due to climate change can lead to heat stress (HS) in plants, which not only hinders plant growth and development but also result in significant losses in crop yields. To cope with the different stresses including HS, plants have evolved a variety of adaptive mechanisms. In response to these stresses, phytohormones play a crucial role by generating endogenous signals that regulate the plant's defensive response. Among these, Ethylene (ET), a key phytohormone, stands out as a major regulator of stress responses in plants and regulates many plant traits, which are critical for crop productivity and nutritional quality. ET is also known as a ripening hormone for decades in climacteric fruit and many studies are available deciphering the function of different ET biosynthesis and signaling components in the ripening process. Recent studies suggest that HS significantly affects fruit quality traits and perturbs fruit ripening by altering the regulation of many ethylene biosynthesis and signaling genes resulting in substantial loss of fruit yield, quality, and postharvest stability. Despite the significant progress in this field in recent years the interplay between ET, ripening, and HS is elusive. In this review, we summarized the recent advances and current understanding of ET in regulating the ripening process under HS and explored their crosstalk at physiological and molecular levels to shed light on intricate relationships.

Perceptions of the health risk from hot days and the cooling effect of urban green spaces: a case study in Xi'an, China

Background

Hot days are one of the typical threats to human health and sustainable cities. The exploration of residents' perceptions of thermal environment and its mitigation measures will support the health risk prevention.

Methods

A survey with a combination of closed-ended and open-ended questions was conducted in July 2021 among 13 urban parks in Xi'an City, China. With the help of ANOVA and ordinal logistic regression, this study investigated the influencing factors both on residents' health risk perception of hot days and their perception of the effect of urban ecological landscape on reducing the thermal risk. The relationship between health risk perception and residents' needs of urban ecological construction was also explored.

Results

According to 325 valid questionnaires, the male-female ratio of respondents was found to be 1:0.87, young people aged 18-29 (26.46%), the retirees (27.08%) and the ones with undergraduate education (33.23%) were, relatively, the largest groups. The results show that 92.31% of the respondents believed that their daily lives were under the influence of hot days. Housing types, occupation, cooling equipment at work, and outdoor working hours all had a significant impact on their high temperature perceptions. The proportion of respondents who were under a huge health risk and sought medical treatment due to hot days was 30.16% and 44.92%, respectively. Women were 18.52 and 2.33 times more likely to suffer health threats and experience discomforts than men. Furthermore, 73.23% of the respondents believed that the urban ecological landscapes in Xi'an had an enhanced cooling effect in recent years. Compared with the morphological characteristics, residents' recognition of the restriction of landscape's area on its cooling effect was higher, and the residence duration showed a significant influence.

Conclusion

The cooling effect of green spaces and water effectively resisted urban thermal threats, and residents' needs of the urban ecological landscapes was associated with their health risk perceptions of hot days. In the future, it is necessary to promote the early warning of hot days, meanwhile, the optimization of landscape patterns of green infrastructures should be implemented in urban planning for the purposes of residents' health risk prevention.

Health Insurance Coverage for Farmworkers in California After the Introduction of the Affordable Care Act: A Mixed-methods Study

BACKGROUND

Previous studies have found that health insurance coverage expanded for farmworkers from 2011-2012 to 2015-2016 due in part to the introduction of the Patient Protection and Affordable Care Act (ACA). This study examines the continued impact of the ACA on insurance coverage for farmworkers to 2018 and identifies barriers to further expansion.

METHODS

A mixed-methods approach was utilized. Weighted statistical analyses were conducted on the National Agriculture Worker Survey (NAWS) data for 2011-2012, 2015-2016, and 2017-2018. Qualitative interviews conducted with agricultural employers, health care providers, and community-based organizations examined the impact of the ACA on health insurance coverage for farmworkers.

RESULTS

Though health insurance coverage for farmworkers in California increased after the introduction of the ACA (from 37.3% in 2011-2012 to 56.5%% in 2015-2016), coverage rates grew only modestly between 2015-2016 and 2017-2018 (64.8%). Coverage rates were higher for documented (43.0% in 2011-2012 and 77.7% in 2017-2018) than for undocumented workers (26% in 2011-2012 and 46.8% in 2017-2018). The results from the qualitative interviews suggested that barriers to increased coverage include the high cost of insurance for growers, high deductibles and copays for farmworkers, and distrust of government agencies.

CONCLUSIONS

While the period after the ACA was associated with notable improvements in health insurance coverage for farmworkers in California, important barriers remain for farmworkers seeking to obtain insurance and for growers seeking to provide coverage.

POLICY IMPLICATIONS

States should consider funding a farmworker-specific Medicaid program to provide health insurance coverage and care coordination across counties and states.

Climate change effects on mental health: are there workplace implications?

BACKGROUND

Climate change can negatively affect mental health, and poor mental health can negatively affect work. However, less is known about the relationship between mental health and workplace behaviours within the climate change context.

AIMS

To explore existing literature relating to climate-induced mental ill-health as a potential predictor of workplace behaviours.

METHODS

Scoping review, searching five databases for relevant literature using two separate search strategies.

RESULTS

Only five studies with any relevant data were found. Results could not be easily synthesized because each of the five considered different work-related outcomes. However, the available data suggest that the psychological impact of extreme events could lead to increased job tension, higher turnover intentions and workplace hostility. Stress about extreme weather could also impede the ability to make essential work-related decisions and, for those who work in the environmental sector, concerns about climate could lead to overcommitment to work. There was some evidence that social support might lessen the effects of climate-induced stress on work outcomes.

CONCLUSIONS

Very little literature considers the impacts of climate change on employees' mental health and associated workplace function. The available evidence suggests there are potential negative impacts which may be mitigated by social support. It is important for future research to explore ways of supporting staff and fostering resilience.

Automation, Climate Change, and the Future of Farm Work: Cross-Disciplinary Lessons for Studying Dynamic Changes in Agricultural Health and Safety

In this review, we first assess the state of agricultural health and safety research as it pertains to the dynamic challenges facing automating agriculture on a warming planet. Then, we turn to social science fields such as rural sociology, science and technology studies, and environmental studies to leverage relevant insights on the introduction of new technologies, environmental risks, and associated workplace hazards. Increased rates of automation in agriculture alongside new risks associated with climate change create the need for anticipatory governance and adaptive research to study novel mechanisms of worker health and safety. The use of the PRISMA framework led to the 137 articles for our review. We identify three themes in the literature on agricultural health and safety: (1) adoption outcomes, (2) discrete cases of health risks, and (3) an emphasis on care and wellbeing in literature on dairy automation Our review led to the identification of research gaps, noting that current research (a) tends to examine these forces separately, instead of together, (b) has not made robust examination of these forces as socially embedded, and (c) has hesitated to examine the broad, transferable themes for how these forces work across industries. In response to these gaps, we suggest that attention to outside disciplines may provide agricultural health and safety research with a toolset to examine needed inquiry into the multiplicity of experiences of rural stakeholders, the industry specific problems arising from automation and climate change, and the socially embedded aspects of agricultural work in the future.

Combined exposure of heat stress and ozone enhanced cognitive impairment via neuroinflammation and blood brain barrier disruption in male rats

BACKGROUND

Heat stress (HS) exposure has been linked to cognitive dysfunction. In reality, high temperature does not occur alone in environment, and ozone (O₃) and heatwaves usually co-exist in atmospheric environment. However, whether O₃ exposure exacerbates HS-induced cognitive impairment and the potential underlying mechanisms have not been explored experimentally. The aim of this study was to determine the co-effects and mechanisms of HS and O₃ on the cognitive dysfunction.

METHODS

48 Sprague Dawley male rats were randomly divided into 4 groups: control, HS, O₃ and HS plus O₃ (HO₃) groups. Rats in HS and HO₃ group were exposed to 40 °C every morning from 9:00 to 12:00 for 15 consecutive days. While rats in O₃ and HO₃ groups were exposed to 0.7 ppm O₃ the same day from 14:00 to 17:00 for 15 days. Cognitive performance was examined with Morris water maze test. Neurodegeneration, glial activation, neuroinflammation, blood brain barrier (BBB) disruption and apoptosis were evaluated by Western blot, Elisa, immunohistochemistry and immunofluorescence staining.

RESULTS

HS induced cognitive decline and neuronal damage in rats. Further studies showed that exposure of rats to HS could also induce glial activation, neuroinflammation and neuronal apoptosis in hippocampus, and decrease in the expressions of ZO-1, claudin-5 and occluding, indicative of BBB disruption. Impressively, the neuronal effects induced by HS, as depicted above, could be worsened by co-exposure to O₃ in rats.

CONCLUSIONS

Co-exposure to O₃ promotes HS-induced cognitive impairment in rats possibly through glial-mediated neuroinflammation and BBB disruption.

Where do you live and what do you do? Two questions that might impact your kidney health

In many cases the social determinants of health need to be assessed through their interaction with environmental factors. This review looks at the impact of physical location and occupation of individuals on their kidney health. It examines the effect of living at high altitude on kidney function and the relationship between extreme cold or hot temperatures and the incidence of kidney injury. It reviews as well the many occupations that have been linked to kidney disease in high-income and low-and-middle-income countries. As a conclusion, this overview proposes preventive recommendations that could be individualized based on weather, altitude, socio-economic level of the country and occupation of the individual.