Role of astrocyte activation in fine particulate matter-enhancement of existing ischemic stroke in Sprague-Dawley male rats

The beneficial effects of lupeol on particulate matter-mediated pulmonary inflammation

Particulate matter (PM) poses significant health risks, especially fine particles (PM2.5) that can cause severe lung injuries. Lupeol, a phytosterol from medicinal plants, has potential anti-cancer properties. This study investigated lupeol's protective effects against PM2.5-induced lung damage. Mice received lupeol following intratracheal PM2.5 exposure. Results showed lupeol reduced lung damage, lowered wet/dry (W/D) weight ratio, and suppressed increased permeability caused by PM2.5. Additionally, lupeol decreased plasma inflammatory cytokines, total protein concentration in bronchoalveolar lavage fluid (BALF), and PM2.5-induced lymphocyte proliferation. Lupeol also reduced expression of toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88), and autophagy-related proteins microtubule-associated protein 1 A/1 B-light chain 3 (LC3) II and Beclin 1, while increasing phosphorylated mammalian target of rapamycin (mTOR) phosphorylation. These findings suggest lupeol's potential as a therapeutic agent for PM2.5-induced lung damage via modulation of the TLR4-MyD88 and mTOR-autophagy pathways.

Plasma proteome mediate the impact of PM2.5 on stroke: A 2-step Mendelian randomization study

The objectives of this study were to measure the mediation effect of plasma proteins and to clarify their mediating role in the relationship between stroke risk and particulate matter 2.5 (PM2.5) exposure. The possible mediating role of plasma proteins on the causative link between PM2.5 exposure and stroke incidence were examined using a two-step Mendelian randomization (MR) approach based on two-sample Mendelian randomization (TSMR). The findings revealed a significant positive causal relationship between PM2.5 exposure and stroke, with an inverse variance weighted odds ratio of 1.219 (95 % CI: 1.002 - 1.482, P < 0.05). Additionally, a positive causal association was identified between PM2.5 exposure and several plasma proteins, including FAM134B, SAP, ITGB7, Elafin, and DCLK3. Among these, FAM134B, ITGB7, Elafin, and DCLK3 also demonstrated a positive causal association with stroke, whereas only SAP was found to be negatively causally associated with stroke. Remarkably, four plasma proteins, namely DCLK3, FAM134B, Elafin, and ITGB7, were identified as mediators, accounting for substantial proportions (14.5 %, 13.6 %, 11.1 %, and 9.9 %) of the causal association between PM2.5 and stroke. These results remained robust across various sensitivity analyses. Consequently, the study highlights the significant and independent impact of PM2.5 on stroke risk and identifies specific plasma proteins as potential targets for preventive interventions against PM2.5-induced stroke.

Particulate Matter-Induced Neurotoxicity: Unveiling the Role of NOX4-Mediated ROS Production and Mitochondrial Dysfunction in Neuronal Apoptosis

Urban air pollution, a significant environmental hazard, is linked to adverse health outcomes and increased mortality across various diseases. This study investigates the neurotoxic effects of particulate matter (PM), specifically PM2.5 and PM10, by examining their role in inducing oxidative stress and subsequent neuronal cell death. We highlight the novel finding that PM increases mitochondrial ROS production via stimulating NOX4 activity, not through its expression level in Neuro-2A cells. Additionally, PMs provoke ROS production via increasing the expression and activity of NOX2 in SH-SY5Y human neuroblastoma cells, implying differential regulation of NOX proteins. This increase in mitochondrial ROS triggers the opening of the mitochondrial permeability transition pore (mPTP), leading to apoptosis through key mediators, including caspase3, BAX, and Bcl2. Notably, the voltage-dependent anion-selective channel 1 (VDAC1) increases at 1 µg/mL of PM2.5, while PM10 triggers an increase from 10 µg/mL. At the same concentration (100 µg/mL), PM2.5 causes 1.4 times higher ROS production and 2.4 times higher NOX4 activity than PM10. The cytotoxic effects induced by PMs were alleviated by NOX inhibitors GKT137831 and Apocynin. In SH-SY5Y cells, both PM types increase ROS and NOX2 levels, leading to cell death, which Apocynin rescues. Variability in NADPH oxidase sources underscores the complexity of PM-induced neurotoxicity. Our findings highlight NOX4-driven ROS and mitochondrial dysfunction, suggesting a potential therapeutic approach for mitigating PM-induced neurotoxicity.

AhR Agonistic Components in Urban Particulate Matter Regulate Astrocytic Activation and Function

Exposure to atmospheric particulate matter (PM) has been found to accelerate the onset of neurological disorders via the induction of detrimental neuroinflammatory responses. To reveal how astrocytes respond to urban atmospheric PM stimulation, a commercially available standard reference material (SRM1648a) was tested in this study on the activation of rat cortical astrocytes. The results showed that SRM1648a stimulation induced both A1 and A2 phenotypes in astrocytes, as characterized by the exposure concentration-dependent increases in Fkbp5, Sphk1, S100a10, and Il6 mRNA levels. Studying the functional alterations of astrocytes indicated that the neurotrophic factors of Gdnf and Ngf were transcriptionally upregulated due to astrocytic A2-type activation. SRM1648a also promoted autonomous motility of astrocytes and elevated the expressions of chemokines. The aryl hydrocarbon receptor (AhR) agonistic components, such as polycyclic aromatic hydrocarbons (PAHs), were recognized to greatly contribute to SRM1648a-induced effects on astrocytes, which was confirmed by the attenuation of PM-disturbed astrocytic effects via AhR blockage. This study, for the first time, uncovered the direct regulation of urban atmospheric PM on astrocytic activation and function and traced the containing bioactive components (e.g., PAHs) with AhR agonistic activity. The findings provided new knowledge on understanding the ambiguous neurological disturbance from ambient fine PM pollution.

Therapeutic effects of hederacolchiside A1 on particulate matter-induced pulmonary injury

Particulate matter (PM) comprises a hazardous mixture of inorganic and organic particles that carry health risks. Inhaling fine PM particles with a diameter of ≤2.5 μm (PM2.5) can promote significant lung damage. Hederacolchiside A1 (HA1) exhibits notable in vivo antitumor effects against various solid tumors. However, our understanding of its therapeutic potential for individuals with PM2.5-induced lung injuries remains limited. Here, we explored the protective properties of HA1 against lung damage caused by PM2.5 exposure. HA1 was administered to the mice 30 min after intratracheal tail vein injection of PM2.5. Various parameters, such as changes in lung tissue wet/dry (W/D) weight ratio, total protein/total cell ratio, lymphocyte counts, inflammatory cytokine levels in bronchoalveolar lavage fluid (BALF), vascular permeability, and histology, were assessed in mice exposed to PM2.5. Our data showed that HA1 mitigated lung damage, reduced the W/D weight ratio, and suppressed hyperpermeability caused by PM2.5 exposure. Moreover, HA1 effectively decreased plasma levels of inflammatory cytokines in those exposed to PM2.5, including tumor necrosis factor-α, interleukin-1β, and nitric oxide, while also lowering the total protein concentration in BALF and successfully alleviating PM2.5-induced lymphocytosis. Furthermore, HA1 significantly decreased the expression levels of toll-like receptor 4 (TLR4), myeloid differentiation primary response (MyD) 88, and autophagy-related proteins LC3 II and Beclin 1 but increased the protein phosphorylation of the mammalian target of rapamycin (mTOR). The anti-inflammatory characteristics of HA1 highlights its potential as a promising therapeutic agent for mitigating PM2.5-induced lung injuries by modulating the TLR4-MyD88 and mTOR-autophagy pathways.

Toxicokinetic study of scandium oxide in rats

Canada has recently invested in the large-scale exploitation of scandium oxide. However, there are no studies available to date to understand its toxicokinetics in the animal or human body, which is necessary to assess exposure and health risks. The aim of this research was to investigate the toxicokinetics of absorbed scandium oxide (Sc2O3) using the rat as an experimental model. Male Sprague-Dawley rats were injected intravenously with 0.3 or 1 mg Sc2O3/kg body weight (bw). Blood and excreta (urine and feces) were collected sequentially during a 21-day period, and main organs (liver, spleen, lungs, kidneys, brain) were withdrawn at sacrifice on day 21. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for the measurement of Sc element in the different samples. The mean residence time (MRTIV) calculated from the blood profile was 19.7 ± 5.9 h and 43.4 ± 24.6 h at the lower and higher doses, respectively. Highest tissue levels of Sc were found in the lungs and liver; respective lung values of 10.6 ± 6.2% and 3.4 ± 2.3% of the Sc dose were observed at the time of sacrifice while liver levels represented 8.9 ± 6.4% and 4.6 ± 1.1%. Elimination of Sc from the body was not complete after 21 days. Cumulative fecal excretion over the 21-day collection period represented 12.3 ± 1.3% and 5.9 ± 1.0% of the lower and higher Sc doses, respectively, and showed a significant effect of the dose on the excretion; only a small fraction of the Sc dose was recovered in urine (0.025 ± 0.016% and 0.011 ± 0.004% in total, respectively). In addition to an effect of the dose on the toxicokinetics, results highlight the importance of the lung as a site of accumulation and retention of Sc2O3, which raises the question of the risks of effects related to respiratory exposure in workers. The results also question the relevance of urine as a matrix for biological exposure monitoring. A more in-depth inhalation toxicokinetic study would be necessary.

Therapeutic Effects of (+)-Afzelechin on Particulate Matter-Induced Pulmonary Injury

Particulate matter (PM) constitutes a hazardous blend of organic and inorganic particles that poses health risks. Inhalation of fine airborne PM with a diameter of ≤ 2.5 μm (PM2.5) can lead to significant lung impairments. (+)-afzelechin (AZC), a natural compound sourced from Bergenia ligulata, boasts a range of attributes, including antioxidant, antimicrobial, anticancer, and cardiovascular effects. However, knowledge about the therapeutic potential of AZC for patients with PM2.5-induced lung injuries remains limited. Thus, in this study, we investigated the protective attributes of AZC against lung damage caused by PM2.5 exposure. AZC was administered to the mice 30 min after intratracheal instillation of PM2.5. Various parameters, such as changes in lung tissue wet/dry (W/D) weight ratio, total protein/total cell ratio, lymphocyte counts, levels of inflammatory cytokines in bronchoalveolar lavage fluid (BALF), vascular permeability, and histology, were evaluated in mice exposed to PM2.5. Data demonstrated that AZC mitigated lung damage, reduced W/D weight ratio, and curbed hyperpermeability induced by PM2.5 exposure. Furthermore, AZC effectively lowered plasma levels of inflammatory cytokines produced by PM2.5 exposure. It reduced the total protein concentration in BALF and successfully alleviated PM2.5-induced lymphocytosis. Additionally, AZC substantially diminished the expression levels of Toll-like receptors 4 (TLR4), MyD88, and autophagy-related proteins LC3 II and Beclin 1. In contrast, it elevated the protein phosphorylation of the mammalian target of rapamycin (mTOR). Consequently, the anti-inflammatory attribute of AZC positions it as a promising therapeutic agent for mitigating PM2.5-induced lung injuries by modulating the TLR4-MyD88 and mTOR-autophagy pathways.

Jujuboside B post-treatment attenuates PM2.5-induced lung injury in mice

Fine particulate matter (PM2.5) is an air pollutant that causes severe lung injury. We investigated the effects of Jujuboside B (JB), a component of Zizyphi Spinosi Semen, on lung toxicity caused by PM2.5, and we identified the mechanism of its protective effect. Lung injury in an animal model was induced by intratracheal administration of a PM2.5 suspension. After 2 days of PM2.5 pretreatment, mice were administered JB via the tail vein three times over a 2-day period. JB significantly reduced the histological lung damage as well as the lung wet/dry weight ratio. JB also considerably reduced PM2.5-induced autophagy dysfunction, apoptosis, inflammatory cytokine levels, and the number of PM2.5-induced lymphocytes in the bronchial alveolar fluid. We conclude that by regulating TLR2, 4-MyD88, and mTOR-autophagy pathways, JB exerts a protective effect on lung injury. Thus, JB can be used as a potential therapeutic agent for PM2.5-induced lung damage.

Particulate matter exposure and neurodegenerative diseases: A comprehensive update on toxicity and mechanisms

Exposure to particulate matter (PM) has been associated with a range of health impacts, including neurological abnormalities that affect neurodevelopment, neuroplasticity, and behavior. Recently, there has been growing interest in investigating the possible relationship between PM exposure and the onset and progression of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and multiple sclerosis. However, the precise mechanism by which PM affects neurodegeneration is still unclear, even though several epidemiological and animal model studies have provided mechanistic insights. This article presents a review of the current research on the neurotoxicity of PM and its impact on neurodegenerative diseases. This review summarizes findings from epidemiological and animal model studies collected through searches in Google Scholar, PubMed, Web of Science, and Scopus. This review paper also discusses the reported effects of PM exposure on the central nervous system and highlights research gaps and future directions. The information presented in this review may inform public health policies aimed at reducing PM exposure and may contribute to the development of new treatments for neurodegenerative diseases. Further mechanistic and therapeutic research will be needed to fully understand the relationship between PM exposure and neurodegenerative diseases.

Therapeutic m6A Eraser ALKBH5 mRNA-Loaded Exosome-Liposome Hybrid Nanoparticles Inhibit Progression of Colorectal Cancer in Preclinical Tumor Models

Although therapeutic targets have been developed for colorectal cancer (CRC) therapy, the therapeutic effects are not ideal and the survival rate for CRC patients remains poor. Therefore, it is crucial to recognize a specific target and develop an efficacious delivery system for CRC therapy. Herein, we demonstrate that reduced ALKBH5 mediates aberrant m⁶A modification and tumor progression in CRC. Mechanically, histone deacetylase 2-mediated H3K27 deacetylation inhibits ALKBH5 transcription in CRC, whereas ectopic ALKBH5 expression decreases tumorigenesis of CRC cells and protects mice from colitis-associated tumor development. Further, METTL14/ALKBH5/IGF2BPs combine to modulate JMJD8 stability in an m⁶A-dependent manner, which increases glycolysis and accelerates the development of CRC by enhancing the enzymatic activity of PKM2. Moreover, ALKBH5 mRNA-loaded folic acid-modified exosome-liposome hybrid nanoparticles were synthesized and significantly inhibit the progression of CRC in preclinical tumor models by modulating the ALKBH5/JMJD8/PKM2 axis and inhibiting glycolysis. Overall, our research confirms the crucial function of ALKBH5 in regulating the m⁶A status in CRC and provides a direct preclinical approach for using ALKBH5 mRNA nanotherapeutics for CRC.

Therapeutic Effects of Cornuside on Particulate Matter-Induced Lung Injury

Particulate matter (PM) is a mixture comprising both organic and inorganic particles, both of which are hazardous to health. The inhalation of airborne PM with a diameter of ≤2.5 μm (PM_2.5) can cause considerable lung damage. Cornuside (CN), a natural bisiridoid glucoside derived from the fruit of Cornus officinalis Sieb, exerts protective properties against tissue damage via controlling the immunological response and reducing inflammation. However, information regarding the therapeutic potential of CN in patients with PM_2.5-induced lung injury is limited. Thus, herein, we examined the protective properties of CN against PM_2.5-induced lung damage. Mice were categorized into eight groups (n = 10): a mock control group, a CN control group (0.8 mg/kg mouse body weight), four PM_2.5+CN groups (0.2, 0.4, 0.6, and 0.8 mg/kg mouse body weight), and a PM_2.5+CN group (0.2, 0.4, 0.6, and 0.8 mg/kg mouse body weight). The mice were administered with CN 30 min following intratracheal tail vein injection of PM_2.5. In mice exposed to PM_2.5, different parameters including changes in lung tissue wet/dry (W/D) lung weight ratio, total protein/total cell ratio, lymphocyte counts, inflammatory cytokine levels in the bronchoalveolar lavage fluid (BALF), vascular permeability, and histology were examined. Our findings revealed that CN reduced lung damage, the W/D weight ratio, and hyperpermeability caused by PM_2.5. Moreover, CN reduced the plasma levels of inflammatory cytokines produced because of PM_2.5 exposure, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and nitric oxide, as well as the total protein concentration in the BALF, and successfully attenuated PM_2.5-associated lymphocytosis. In addition, CN substantially reduced the expression levels of Toll-like receptors 4 (TLR4), MyD88, and autophagy-related proteins LC3 II and Beclin 1, and increased protein phosphorylation of the mammalian target of rapamycin (mTOR). Thus, the anti-inflammatory property of CN renders it a potential therapeutic agent for treating PM_2.5-induced lung injury by controlling the TLR4-MyD88 and mTOR-autophagy pathways.

Atmospheric particulate matter impairs cognition by modulating synaptic function via the nose-to-brain route

Atmospheric particulate matter (PM), a ubiquitous air pollutant, is the leading environmental risk factor for mortality worldwide. Experimental and epidemiological studies consistently suggest a strong link between long-term exposure to PM_2.5 (<2.5 μm, fine PM) and cognitive impairment. The neuroinflammatory response is presumed to be one of the main mechanisms of PM_2.5-induced cognitive impairment, possibly leading to synaptic dysfunction. However, the main route and mechanism underlying the cause of cognitive dysfunction and pathogenic alterations in PM_2.5-exposure mice remain poorly understood. Therefore, this study aimed to investigate the main route and mechanism of PM_2.5-induced cognitive impairment. Our results showed that PM_2.5 directly entered the brain following nasal administration, and both the short-term PM_2.5 administration via atomization and nasal drops induced learning and memory impairments and neuronal damage in adult mice. Moreover, astrocytes and microglia were both activated in the two short-term PM_2.5 exposure models, while few changes in the inflammatory response were observed in the peripheral circulatory system. Furthermore, a further transcriptional analysis revealed that short-term PM_2.5 administration led to cognitive impairment mainly by modulating synaptic functions and that although glia were activated, the glia-related pathological pathways were not significantly activated. Notably, following PM_2.5 exposure, PLX3397-induced microglial deletion did not restore the cognitive function of the mice. In conclusion, our results provide evidence that PM_2.5 enters the brain via the nose-to-brain route to impair cognitive function, and short-term exposure to PM_2.5 directly alters synaptic function rather than the neuroinflammatory response to affect cognition.

Short-term PM2.5 exposure and cognitive function: Association and neurophysiological mechanisms

BACKGROUND

Although converging evidence has demonstrated that exposure to fine particulate matter (PM_2.5) caused adverse effects on brain structure and cognitive function, the association between the short-term exposure to PM_2.5 and cognition dysfunction remained underexplored, especially possible neurophysiological mechanisms.

METHODS

We conducted a longitudinal observational study with four repeated measurement sessions among 90 young adults from September 2020 to June 2021. During each measurement session, we measured participants' personal-level air pollution exposure for one week with portable monitors, followed by executive function assessment and electrophysiological signal recording at an assessment center. Standard Stroop color-word test was used accompanied with electroencephalogram (EEG) recording to assess performance on executive function. We used linear mixed-effect model with lagged values of PM_2.5 levels to analyze the association between PM_2.5 exposure and changes in executive function, and mediation analysis to investigate mediation effect by EEG signal.

RESULTS

Adjusted mixed-effect models demonstrated that elevated PM_2.5 exposure three days prior to cognitive assessment (lag-3) was associated with (1) declined performance in both congruent and incongruent tasks in Stroop test, (2) reduced lower and upper alpha event-related desynchronization (ERD) during 500-1000 ms after stimuli, both indicating impaired executive control. Lower and upper alpha ERD also mediated observed associations between short-term PM_2.5 exposure and executive function. No significant associations were found between short-term PM_2.5 exposure or aperiodic exponents in tonic and phasic states, or periodic alpha oscillations in tonic state.

CONCLUSION

Our results provided evidence that short-term PM_2.5 exposure was associated with executive dysfunction. Reduced alpha ERD was likely to be the underlying pathway through which PM_2.5 induced adverse effects on neuron activities during cognitive tasks.

Cirsilineol Treatment Attenuates PM2.5-Induced Lung Injury in Mice

Ultrafine particulate matter with less than 2.5 μm diameter (PM_2.5) is an air pollutant that causes severe lung damage. Currently, effective treatment and preventive methods for PM_2.5-induced lung damage are limited. Cirsilineol (CSL) is a small natural compound isolated from Artemisia vestita. In this study, the efficacy of CSL on PM_2.5-induced lung toxicity was tested, and its mechanism was identified. Lung injury was caused by intratracheal administration of PM_2.5 suspension in animal models. Two days after PM_2.5 pretreatment, CSL was injected via mouse tail vein for two days. The effects of CSL on PM_2.5-induced lung damage, autophagy, apoptosis, and pulmonary inflammation in a mouse model and their mechanisms were investigated. CSL significantly suppressed histological lung damage and lung wet/dry weight proportion. CSL also significantly reduced PM_2.5-induced autophagy dysfunction, apoptosis, lymphocyte suppression, and inflammatory cytokine levels in bronchoalveolar fluid (BALF). Furthermore, CSL increased mammalian target of rapamycin (mTOR) phosphorylation and significantly inhibited the expression of Toll-like receptors (TLR) 2 and 4, MyD88, and the autophagy proteins, Beclin1 and LC3II. Thus, CSL exerts protective effects on pulmonary damage by regulating mTOR and TLR2,4-myD88 autophagy pathways. Therefore, CSL can be used as an effective treatment for PM_2.5-induced lung damage.

The underlying mechanism of PM2.5-induced ischemic stroke

Under the background of global industrialization, PM_2.5 has become the fourth-leading risk factor for ischemic stroke worldwide, according to the 2019 GBD estimates. This highlights the hazards of PM_2.5 for ischemic stroke, but unfortunately, PM_2.5 has not received the attention that matches its harmfulness. This article is the first to systematically describe the molecular biological mechanism of PM_2.5-induced ischemic stroke, and also propose potential therapeutic and intervention strategies. We highlight the effect of PM_2.5 on traditional cerebrovascular risk factors (hypertension, hyperglycemia, dyslipidemia, atrial fibrillation), which were easily overlooked in previous studies. Additionally, the effects of PM_2.5 on platelet parameters, megakaryocytes activation, platelet methylation, and PM_2.5-induced oxidative stress, local RAS activation, and miRNA alterations in endothelial cells have also been described. Finally, PM_2.5-induced ischemic brain pathological injury and microglia-dominated neuroinflammation are discussed. Our ultimate goal is to raise the public awareness of the harm of PM_2.5 to ischemic stroke, and to provide a certain level of health guidance for stroke-susceptible populations, as well as point out some interesting ideas and directions for future clinical and basic research.

Fine particulate matter exposure aggravates ischemic injury via NLRP3 inflammasome activation and pyroptosis

Aims

Accumulating evidence has suggested that airborne fine particulate matter (PM2.5) exposure is associated with an increased risk of ischemic stroke. However, the underlying mechanisms have not been fully elucidated. In this study, we aim to investigate the role and mechanisms of NLRP3 inflammasome and pyroptosis in ischemic stroke after PM2.5 exposure.

Methods

The BV‐2 and HMC‐3 microglial cell lines were established and subjected to oxygen–glucose deprivation and reoxygenation (OGD/R) with or without PM2.5 exposure. We used the CCK‐8 assay to explore the effects of PM2.5 on cell viability of BV‐2 and HMC‐3 cells. Then, the effects of PM2.5 exposure on NLRP3 inflammasome and pyroptosis following OGD/R were detected by western blotting, ELISA, and the confocal immunofluorescence staining. Afterwards, NLRP3 was knocked down to further validate the effects of PM2.5 on cell viability, NLRP3 inflammasome activation, and pyroptosis after OGD/R in HMC‐3 cells. Finally, the intracellular reactive oxygen species (ROS) was measured and the ROS inhibitor N‐acetyl‐L‐cysteine (NAC) was used to investigate whether ROS was required for PM2.5‐induced NLRP3 inflammasome activation and pyroptosis under ischemic conditions.

Results

We found that PM2.5 exposure decreased the viability of BV‐2 and HMC‐3 cells in a dose‐ and time‐dependent manner under ischemic conditions. Furthermore, PM2.5 exposure aggravated NLRP3 inflammasome activation and pyroptosis after OGD/R, as indicated by an increased expression of NLRP3, ASC, pro‐caspase‐1, Caspase‐1, GSDMD, and GSDMD‐N; increased production of IL‐1β and IL‐18; and enhanced Caspase‐1 activity and SYTOX green uptake. However, shRNA NLRP3 treatment attenuated the effects of PM2.5 on cell viability, NLRP3 inflammasome activation, and pyroptosis. Moreover, we observed that PM2.5 exposure increased the production of intracellular ROS following OGD/R, while inhibiting ROS production with NAC partially attenuated PM2.5‐induced NLRP3 inflammasome activation and pyroptosis under ischemic conditions.

Conclusion

These results suggested that PM2.5 exposure triggered the activation of NLRP3 inflammasome and pyroptosis under ischemic conditions, which may be mediated by increased ROS production after ischemic stroke. These findings may provide a more enhanced understanding of the interplay between PM2.5 and neuroinflammation and cell death, and reveal a novel mechanism of PM2.5‐mediated toxic effects after ischemic stroke.

An Air Particulate Pollutant Induces Neuroinflammation and Neurodegeneration in Human Brain Models

Fine particulate matter (PM2.5), a major component among air pollutants, highlights as a global health concern. Several epidemiological studies show the correlation between chronical PM2.5 exposure and incidents of neurological disorders including Alzheimer's disease. However, the mechanisms have not been well understood, partly due to the lack of model systems that reflect the physiologically relevant innate immunity in human brains. Here, PM2.5-polluted human brain models (PMBs) are created in a 3D microfluidic platform reconstituting key aspects of human brain immunity under the PM2.5 exposure. PM2.5 penetration across a blood-brain barrier (BBB) model and accumulation in the brain tissue side of the model are first validated. Second, the PMB model shows that the BBB-penetrating PM2.5 initiates astrogliosis, resulting in slight neuronal loss and microglial infiltration. Third, it is demonstrated that the infiltrating microglia obtain M1 phenotype induced by interleukin-1β and interferon-γ from neurons and reactive astrocytes under the PM2.5 exposure. Finally, it is observed that additional proinflammatory mediators and nitric oxide released from the M1 microglia exacerbate neuronal damages, such as synaptic impairment, phosphoric tau accumulation, and neuronal death. This study suggests that PM2.5 can be a potential environmental risk factor for dementia mediated by the detrimental neuroinflammation.

Endothelium-derived Cdk5 deficit aggravates air pollution-induced peripheral vasoconstriction through AT1R upregulation

PM_2.5 infiltrates into circulation and increases the risk of systemic vascular dysfunction. As the first-line barrier against external stimuli, the molecular mechanism of the biological response of vascular endothelial cells to PM_2.5 exposure remains unclear. In this study, 4-week-old mice were exposed to Hangzhou 'real' airborne PM_2.5 for 2 months and were found to display bronchial and alveolar damage. Importantly, in the present study, we have demonstrated that Cdk5 deficit induced peripheral vasoconstriction through angiotensin II type 1 receptor under angiotensin II stimulation in Cdh5-cre;Cdk5^f/n mice. In the brain, Cdk5 deficit increased the myogenic activity in the medullary arterioles under external pressure. On the other hand, no changes in cerebral blood flow and behavior patterns were observed in the Cdh5-cre;Cdk5^f/n mice exposed to PM_2.5. Therefore, our current findings indicate that CDK5 plays an important role in endothelium cell growth, migration, and molecular transduction, which is also a sensor for the response of vascular endothelial cells to PM_2.5.

A mechanistic view on the neurotoxic effects of air pollution on central nervous system: risk for autism and neurodegenerative diseases

Many reports have shown a strong association between exposure to neurotoxic air pollutants like heavy metal and particulate matter (PM) as an active participant and neurological disorders. While the effects of these toxic pollutants on cardiopulmonary morbidity have principally been studied, growing evidence has shown that exposure to polluted air is associated with memory impairment, communication deficits, and anxiety/depression among all ages. So, these toxic pollutants in the environment increase the risk of neurodegenerative disease, ischemia, and autism spectrum disorders (ASD). The precise mechanisms in which air pollutants lead to communicative inability, social inability, and declined cognition have remained unknown. Various animal model studies show that amyloid precursor protein (APP), processing, oxidant/antioxidant balance, and inflammation pathways change following the exposure to constituents of polluted air. In the present review study, we collect the probable molecular mechanisms of deleterious CNS effects in response to various air pollutants.

An Exploratory Study of the Relationships Between Diesel Engine Exhaust Particle Inhalation, Pulmonary Inflammation and Anxious Behavior

Recent technical developments brought negative side effects such as air pollution and large-scale fires, increasingly exposing people to diesel engine exhaust particles (DEP). Testing how DEP inhalation triggers pathophysiology in animal models could be useful in determining how it affects humans. To this end, the aim of this study was to investigate the effects of pulmonary exposure to DEP for seven consecutive days in experimental male C5BL6/N mice. Twenty-four C5BL6/N mice were treated with one of the three test materials: distilled water for control, a low DEP exposure (5 mg/kg), or a high DEP exposure (15 mg/kg). Exposure to DEP induced decreased body weight; however, it gradually increased pulmonary weight in a DEP-dose-dependent manner. DEP exposure significantly elevated soot accumulation in the lungs, with the alteration of pulmonary homeostasis. It also elevated infiltrated immune cells, thus significantly increasing inflammatory cytokine mRNA and protein production in the lungs and broncho-alveolar lavage fluid, respectively. Pulmonary DEP exposure also altered behavioral responses in the open field test (OFT). Low exposure elevated moving distance and speed, while significantly decreasing the number of trials to enter the central zone. Different concentrations of DEP resulted in different behavioral changes; however, while anxiety levels increased, their degree was independent of DEP concentrations. Results suggest that DEP exposure may possess pro-inflammatory responses in the lungs and trigger anxiety.

Inhibitory functions of cardamonin against particulate matter-induced lung injury through TLR2,4-mTOR-autophagy pathways

Particulate matter with an aerodynamic diameter equal to or less than 2.5 μm (PM_2.5) is a form of air pollutant that causes significant lung damage when inhaled. Cardamonin, a flavone found in Alpinia katsumadai Heyata seeds, has been reported to have anti-inflammatory and anticoagulative activity. The aim of this study was to determine the protective effects of cardamonin on PM_2.5-induced lung injury. Mice were treated with cardamonin via tail-vein injection 30 min after the intratracheal instillation of PM_2.5. The results showed that cardamonin markedly reduced the pathological lung injury, lung wet/dry weight ratio, and hyperpermeability caused by PM_2.5. Cardamonin also significantly inhibited PM_2.5-induced myeloperoxidase (MPO) activity in lung tissue, decreased the levels of PM_2.5-induced inflammatory cytokines and effectively attenuated PM_2.5-induced increases in the number of lymphocytes in the bronchoalveolar lavage fluid (BALF). And, cardamonin increased the phosphorylation of mammalian target of rapamycin (mTOR) and dramatically suppressed the PM_2.5-stimulated expression of toll-like receptor 2 and 4 (TLR 2,4), MyD88, and the autophagy-related proteins LC3 II and Beclin 1. In conclusion, these findings indicate that cardamonin has a critical anti-inflammatory effect due to its ability to regulate both the TLR2,4-MyD88 and mTOR-autophagy pathways and may thus be a potential therapeutic agent against PM_2.5-induced lung injury.

Ambient Air Pollution Increases the Risk of Cerebrovascular and Neuropsychiatric Disorders through Induction of Inflammation and Oxidative Stress

Exposure to ambient air pollution is a well-established determinant of health and disease. The Lancet Commission on pollution and health concludes that air pollution is the leading environmental cause of global disease and premature death. Indeed, there is a growing body of evidence that links air pollution not only to adverse cardiorespiratory effects but also to increased risk of cerebrovascular and neuropsychiatric disorders. Despite being a relatively new area of investigation, overall, there is mounting recent evidence showing that exposure to multiple air pollutants, in particular to fine particles, may affect the central nervous system (CNS) and brain health, thereby contributing to increased risk of stroke, dementia, Parkinson's disease, cognitive dysfunction, neurodevelopmental disorders, depression and other related conditions. The underlying molecular mechanisms of susceptibility and disease remain largely elusive. However, emerging evidence suggests inflammation and oxidative stress to be crucial factors in the pathogenesis of air pollution-induced disorders, driven by the enhanced production of proinflammatory mediators and reactive oxygen species in response to exposure to various air pollutants. From a public health perspective, mitigation measures are urgent to reduce the burden of disease and premature mortality from ambient air pollution.

Characterization of tissue and functional deficits in a clinically translational pig model of acute ischemic stroke

The acute stroke phase is a critical time frame used to evaluate stroke severity, therapeutic options, and prognosis while also serving as a major tool for the development of diagnostics. To further understand stroke pathophysiology and to enhance the development of treatments, our group developed a translational pig ischemic stroke model. In this study, the evolution of acute ischemic tissue damage, immune responses, and functional deficits were further characterized. Stroke was induced by middle cerebral artery occlusion in Landrace pigs. At 24 h post-stroke, magnetic resonance imaging revealed a decrease in ipsilateral diffusivity, an increase in hemispheric swelling resulting in notable midline shift, and intracerebral hemorrhage. Stroke negatively impacted white matter integrity with decreased fractional anisotropy values in the internal capsule. Like patients, pigs showed a reduction in circulating lymphocytes and a surge in neutrophils and band cells. Functional responses corresponded with structural changes through reductions in open field exploration and impairments in spatiotemporal gait parameters. Characterization of acute ischemic stroke in pigs provided important insights into tissue and functional-level assessments that could be used to identify potential biomarkers and improve preclinical testing of novel therapeutics.

Recent advances in understanding the mechanisms of PM2.5-mediated neurodegenerative diseases

PM_2.5 particles are widely believed to be associated with respiratory and cardiovascular diseases. However, recent studies have reported that PM_2.5 may be associated with neurodegenerative diseases. The exact mechanism by which PM_2.5 mediates neurotoxicity and cognitive dysfunction is still unclear. In the current work, we collected evidence supporting the association between PM_2.5 exposure and development of neurodegenerative disorders. Evidence from epidemiological investigations, animal experiments, and ex vivo cell experiments showed that PM_2.5 exposure may lead to neuroinflammation, oxidative stress, mitochondrial dysfunction, neuronal apoptosis, synaptic damage and ultimately neurodegenerative diseases.

Polygalasaponin F inhibits neuronal apoptosis induced by oxygen-glucose deprivation and reoxygenation through the PI3K/Akt pathway

Cerebral ischaemia is a common cerebrovascular disease and often induces neuronal apoptosis, leading to brain damage. Polygalasaponin F (PGSF) is one of the components in Polygala japonica Houtt, and it is a triterpenoid saponin monomer. This research focused on anti-apoptotic effect of PGSF during oxygen-glucose deprivation and reoxygenation (OGD/R) injury in rat adrenal pheochromocytoma cells (PC12) and primary rat cortical neurons. OGD/R treatment reduced viability of PC12 cells and primary neurons. This reduced viability was prevented by PGSF, as shown by MTT assay. OGD/R insult decreased expression of Bcl-2/Bax both in PC12 cells and primary neurons but elevated levels of caspase-3 in primary neurons. However, PGSF may up-regulate expression of Bcl-2/Bax and down-regulate caspase-3 in these particular cells. Furthermore, Bcl-2/Bax and the ratio between phosphorylated Akt and total Akt were decreased in PC12 cells treated with OGD/R, and both were increased by PGSF. Moreover, increase in the ratios of Bcl-2/Bax and phosphorylated Akt/total Akt in PC12 cells was suppressed by phosphatidylinositol 3-kinase (PI3K) inhibitor. Data suggest PGSF might prevent OGD/R-induced injury via activation of PI3K/Akt signalling. The ability of PGSF to block the effects of OGD/R appears to involve regulation of Bcl-2, Bax and caspase-3, which are related to apoptosis.

Inhibitory functions of maslinic acid on particulate matter-induced lung injury through TLR4-mTOR-autophagy pathways

Particulate matter (PM), the collection of all liquid and solid particles suspended in air, includes both organic and inorganic particles, many of which are health-hazards. PM particles with a diameter equal to or less than 2.5 μm (PM_2.5) is a form of air pollutant that causes significant lung damage when inhaled. Maslinic acid (MA) prevents oxidative stress and pro-inflammatory cytokine generation, but there is little information available regarding its role in PM-induced lung injury. Therefore, the purpose of this study was to determine the protective activity of MA against PM_2.5-induced lung injury. The mice were divided into seven groups (n = 10 each): a mock control group, an MA control (0.8 mg/kg mouse body weight) group, an opted PM_2.5 produced from diesel (10 mg/kg mouse body weight) group, a diesel PM_2.5+MA (0.2, 0.4, 0.6, and 0.8 mg/kg mouse body weight) groups. Mice were treated with MA via tail-vein injection 30 min after the intratracheal instillation of a diesel PM_2.5. Changes in the wet/dry weight ratio of the lung tissue, total protein/total cell and lymphocyte counts, inflammatory cytokines in the bronchoalveolar lavage fluid (BALF), vascular permeability, and histology were monitored in diesel PM_2.5-treated mice. The results showed that MA reduced pathological lung injury, the wet/dry weight ratio of the lung tissue, and hyperpermeability caused by diesel PM_2.5. MA also inhibited diesel PM_2.5-induced myeloperoxidase (MPO) activity in the lung tissue, decreased the levels of diesel PM_2.5-induced inflammatory cytokines, including tumor necrosis factor (TNF)-α and interleukin (IL)-1β, reduced nitric oxide (NO) and total protein in the BALF, and effectively attenuated diesel PM_2.5-induced increases in the number of lymphocytes in the BALF. In addition, MA increased the protein phosphorylation of the mammalian target of rapamycin (mTOR) and dramatically suppressed diesel PM_2.5-stimulated expression of toll-like receptor 4 (TLR4), MyD88, and the autophagy-related proteins LC3 II and Beclin 1. In conclusion, these findings indicate that MA has a critical anti-inflammatory effect due to its ability to regulate both the TLR4-MyD88 and mTOR-autophagy pathways and may thus be a potential therapeutic agent against diesel PM_2.5-induced lung injury.

Mitochondrial Bioenergetics in Brain Following Ozone Exposure in Rats Maintained on Coconut, Fish and Olive Oil-Rich Diets

Dietary supplementation with omega-3 and omega-6 fatty acids offer cardioprotection against air pollution, but these protections have not been established in the brain. We tested whether diets rich in omega-3 or -6 fatty acids offered neuroprotective benefits, by measuring mitochondrial complex enzyme I, II and IV activities and oxidative stress measures in the frontal cortex, cerebellum, hypothalamus, and hippocampus of male rats that were fed either a normal diet, or a diet enriched with fish oil olive oil, or coconut oil followed by exposure to either filtered air or ozone (0.8 ppm) for 4 h/day for 2 days. Results show that mitochondrial complex I enzyme activity was significantly decreased in the cerebellum, hypothalamus and hippocampus by diets. Complex II enzyme activity was significantly lower in frontal cortex and cerebellum of rats maintained on all test diets. Complex IV enzyme activity was significantly lower in the frontal cortex, hypothalamus and hippocampus of animals maintained on fish oil. Ozone exposure decreased complex I and II activity in the cerebellum of rats maintained on the normal diet, an effect blocked by diet treatments. While diet and ozone have no apparent influence on endogenous reactive oxygen species production, they do affect antioxidant levels in the brain. Fish oil was the only diet that ozone exposure did not alter. Microglial morphology and GFAP immunoreactivity were assessed across diet groups; results indicated that fish oil consistently decreased reactive microglia in the hypothalamus and hippocampus. These results indicate that acute ozone exposure alters mitochondrial bioenergetics in brain and co-treatment with omega-6 and omega-3 fatty acids alleviate some adverse effects within the brain.

Particulate Matter Emissions of Four Different Cigarette Types of One Popular Brand: Influence of Tobacco Strength and Additives

The inhalation of particulate matter (PM) in second-hand smoke (SHS) is hazardous to health of smokers and non-smokers. Tobacco strength (amount of tar, nicotine, and carbon monoxide) and different additives might have an effect on the amount of PM. This study aimed to investigate the influence of tobacco strength or additives on PM. Four cigarette types of the brand Marlboro with different strengths and with or without additives were analyzed in comparison to the 3R4F reference cigarette. SHS was generated by an automatic environmental tobacco smoke emitter (AETSE) in an enclosed space with a volume of 2.88 m³. PM concentrations (PM10, PM2.5, PM₁) were measured with a laser aerosol spectrometer followed by statistical analysis. The two strongest Marlboro brands (Red and Red without additives) showed the highest PM concentrations of all tested cigarettes. The measured mean concentrations Cmean of PM10 increased up to 1458 µg/m³ for the Marlboro Red without additives (PM2.5: 1452 µg/m³, PM₁: 1263 µg/m³). The similarly strong Marlboro Red showed very similar PM values. The second strongest type Marlboro Gold showed 36% (PM10, PM2.5) and 32% (PM₁) lower values, respectively. The "lightest" type Marlboro Silver Blue showed 54% (PM10, PM2.5) or 50% (PM₁) lower PM values. The results indicate that the lower the tar, nicotine, and carbon monoxide amounts, as well as the longer the cigarette filter, the lower are the PM levels. An influence of additives could not be determined.

Particulate matter emissions of four types of one cigarette brand with and without additives: a laser spectrometric particulate matter analysis of secondhand smoke

OBJECTIVE

Inhaled particulate matter (PM) in secondhand smoke (SHS) is deleterious for smokers and non-smokers. Different additives in cigarettes might effect the amount of PM. This study aimed to assess the influence of additives on the PM emissions from different cigarette types in SHS.

DESIGN

An experimental study of PM measuring in SHS of cigarettes without exposition of any person.

METHOD

The concentrations of PM (PM10, PM2.5 and PM1) in SHS of four different types of cigarettes of the brand Lucky Strike, two types with additives (Original Red, Original Blue) and two types without additives (Straight Red, Straight Blue), in comparison to the reference cigarette 3R4F were analysed. An automatic environmental tobacco smoke emitter generated SHS in an enclosed space with a volume of 2.88 m3. PM was measured with a laser aerosol spectrometer (Grimm model 1.109). Afterwards, the measuring values of the four Lucky Strike brands and the reference cigarette were statistically evaluated and visualised.

RESULTS

Lucky Strike Straight Blue, a cigarette type without additives and lower tar amount, showed 10% to 25% lower PM mean values compared with the other tested Lucky Strike products, but 21% (PM1) respectively 27% (PM2.5,PM10) higher mean values than the reference cigarette. The PM mean of all measured smoke-free baseline values (clean air) was 1.6 µg/m³. It increased up to about 1800 µg/m³ for the reference cigarette and up to about 3070 µg/m³ for the Lucky Strike Original Blue.

CONCLUSIONS

The findings of this study show the massive increase of PM amount by smoking cigarettes in enclosed spaces and suggest that additives in tobacco products increase the PM amount in SHS. For validation, further comparative studies are necessary focusing on the comparison of the PM concentration of cigarettes with and without additives.

IMPLICATIONS

Due to the exposure to SHS, 890 000 people die each year worldwide. PM in SHS endangers the health of both non-smokers and smokers. This study considers the effect of additives like aromatics and humectant agents in cigarettes on PM in SHS. Do additives in tobacco products increase the amount of PM?

Comprehensive hippocampal metabolite responses to PM2.5 in young mice

Fine particulate matter (PM_2.5) exposure alters brain development, clinical cognition and behavior in childhood. Previous studies of this subject have mainly been epidemiological investigations or analyses of gene and protein levels; however, gas chromatography-mass spectrometry (GC-MS)-based metabolic profiling, which will help clarify the molecular mechanisms of susceptibility in PM_2.5-induced neurotoxicity, is lacking. In the present study, C57BL/6 mice at different ages (4 weeks, 4 months and 10 months) received oropharyngeal aspiration of PM_2.5 (3 mg/kg) every other day for 4 weeks. The Morris water maze showed that PM_2.5 exposure caused deterioration of spatial learning and memory in young (4 week old) mice. In addition, the levels of several metabolites belonging to different metabolite classes were significantly changed by PM_2.5 exposure in 4-week-old mice. Based on metabolic pathway analysis, we speculated that the decline in spatial learning and memory due to PM_2.5 exposure may be directly or indirectly associated with hippocampal region-specific metabolic alterations involving energy metabolism (citric acid, succinic acid, malic acid, maltose and creatinine); cholesterol metabolism (desmosterol, lanosterol and campesterol); arachidonic acid metabolism (methyl arachidonic acid, nonanoic acid and linoleic acid); inositol phosphate metabolism (myo-inositol, myo-inositol-1-phosphate and methyl-phosphate) and aspartic acid metabolism (aspartic acid, asparagine and homoserine).

DR4 mediates the progression, invasion, metastasis and survival of colorectal cancer through the Sp1/NF1 switch axis on genomic locus

The single nucleotide polymorphism (SNP), -397G > T (rs13278062) polymorphism, in the promoter of Death Receptor 4 (DR4) had been reported to be associated with a significantly increased risk for bladder cancer. However, the association of this SNP with the risk of colorectal cancer has not been reported. In this study, we performed a case-control study in 1,078 colorectal cancer patients and 1,175 matched healthy controls to evaluate the association of the potential functional genetic variants in DR4 with risk and survival of colorectal cancer. PCR-TaqMan were used to genotype the rs13278062, rs1000294 and rs2235126 polymorphisms. We found that subjects carrying the rs13278062 GT/TT genotypes had a significantly lower risk and increased survival time when compared to the GG genotype. We also constructed the rs13278062 GT/TT genotype in SW480 and SW620 cells (rs13278062 is GG in both cell lines) with the CRISPR/Cas9 system. Flow cytometry experiments showed that the rs13278062 TT genotype promoted apoptosis in colorectal cancer cells. In vitro and in vivo experiments established that the rs13278062 G to T mutation inhibited carcinogenesis and metastasis of colorectal cancer. Chromatin immunoprecipitation (ChIP) assays revealed that the rs13278062 G > T polymorphism altered the binding affinity of the transcription factors Sp1/NF1 to the rs13278062 mutation region. Immunohistochemistry, western blot, and qPCR corroborated that the rs13278062 GT/TT genotypes increased the expression of DR4 protein in colorectal cancer tissues and cells. In conclusion, these findings indicate that DR4 mediated progression, invasion, metastasis and survival of colorectal cancer via the Sp1/NF1 switch axis on genomics locus.

In Vitro and In Vivo Experimental Studies of PM2.5 on Disease Progression

Air pollution is a very critical issue worldwide, particularly in developing countries. Particulate matter (PM) is a type of air pollution that comprises a heterogeneous mixture of different particle sizes and chemical compositions. There are various sources of fine PM (PM2.5), and the components may also have different effects on people. The pathogenesis of PM2.5 in several diseases remains to be clarified. There is a long history of epidemiological research on PM2.5 in several diseases. Numerous studies show that PM2.5 can induce a variety of chronic diseases, such as respiratory system damage, cardiovascular dysfunction, and diabetes mellitus. However, the epidemiological evidence associated with potential mechanisms in the progression of diseases need to be proved precisely through in vitro and in vivo investigations. Suggested mechanisms of PM2.5 that lead to adverse effects and chronic diseases include increasing oxidative stress, inflammatory responses, and genotoxicity. The aim of this review is to provide a brief overview of in vitro and in vivo experimental studies of PM2.5 in the progression of various diseases from the last decade. The summarized research results could provide clear information about the mechanisms and progression of PM2.5-induced disease.

PM2.5 inhalation induces intracranial atherosclerosis which may be ameliorated by omega 3 fatty acids

BACKGROUND

Intracranial atherosclerosis (ICA) a major health problem. This study investigated whether inhalation of fine airborne particulate matters (PM2.5) causes ICA and whether omega-3 fatty acids (O3FA) attenuated the development of ICA.

RESULTS

Twelve but not 6 week exposure significantly increased triglycerides (TG) in normal chow diet (NCD), while PM2.5 enhanced all lipid profiles (TG, low density lipoprotein (LDL) and cholesterol (CHO)) after both 6 and 12-week exposure with high-cholesterol diet (HCD). PM2.5 exposure for 12 but not 6 weeks significantly induced middle cerebral artery (MCA) narrowing and thickening, in association with the enhanced expression of inflammatory cytokines, (interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1), interferon gamma (IFN-γ)), vascular cell adhesion molecule 1 (VCAM-1) and inducible nitric oxide synthase (iNOS). O3FA significantly attenuated vascular alterations, even without favorable changes in lipid profiles, in association with reduced expression of IL-6, TNF-α, MCP-1, IFN-γ, VCAM-1 and iNOS in brain vessels.

CONCLUSIONS

PM2.5 exposure for 12 weeks aggravates ICA in a dietary model (HCD + short-term L-NAME), which may be mediated by vascular inflammation. O3FA dietary supplementation prevents ICA development and inflammatory reaction in cerebral vessels.

METHODS

Adult Sprague-Dawly rats were under filtered air (FA) or PM2.5 exposure with NCD or HCD for 6 or 12 weeks. Half of the HCD rats were treated with O3FA (5 mg/kg/day) by gavage. A total of 600 mg NG-nitro-L-arginine methyl ester (L-NAME, 3 mg/mL) per rat was administered over two weeks as supplementation in the HCD group. Blood lipids, including LDL, CHO, TG and high density lipoprotein (HDL), were measured at 6 and 12 weeks. ICA was determined by lumen diameter and thickness of the MCA. Inflammatory markers, IL-6, TNF-α, MCP-1, IFN-γ, VCAM-1 and iNOS were assessed by real-time PCR for mRNA and Western blot for protein expression.

Protective Effects of Ambient Ozone on Incidence and Outcomes of Ischemic Stroke in Changzhou, China: A Time-Series Study

The potential beneficial effect of ozone (O₃) on stroke had been identified experimentally and clinically, but these effects remain controversial in population-based studies. This study aimed to explore the epidemiological association between O₃ and risk of ischemic stroke. Ischemic stroke related health data and air pollution data were obtained from the Center for Disease Control and Prevention and Environmental Monitoring Center in Changzhou between 2015 and 2016, respectively. The associations between the short-term exposure to O₃ and daily ischemic stroke onsets and deaths were examined based on time-series generalized additive Poisson model. During the study period, daily ischemic stroke onsets and deaths decreased 0.340% (95% confidence interval (CI) −0.559% to −0.120%) and 0.697% (95% CI −1.103% to −0.290%) with an interquartile range (IQR) (41.1 µg/m³) increase in levels of ambient O₃, respectively. The protective effects of O₃ were more significant in men and elders and in the cool season than those in women and young people and in the warm season, respectively. The negative association was independent of PM_2.5, PM₁₀, SO₂, NO₂ or CO exposure. Acute O₃ exposure was associated with decreased risk of ischemic stroke. These findings will help provide new insights into the relationship between ischemic stroke and ambient O₃ concentrations.