Mechanism of NO2-induced migraine in rats: The exploration of the role of miR-653-3p/IGF1 axis

Migraine is a severely disabling primary neurological disorder. Although some studies have confirmed that nitrogen dioxide (NO2) pollution increases the risk of migraine, and our previous study demonstrated the role of the channel protein transient receptor potential cation channel subfamily V member 1 (TRPV1) in NO2-induced migraine, the underlying mechanisms have not been fully elucidated. This study aimed to explore the intrinsic toxicity mechanism of NO2-induced migraines using transcriptome sequencing. First, the differentially expressed genes in NO2-induced migraine, insulin-like growth factor 1 (IGF1) and miRNA miR-653-3p were identified using RNA and small RNA sequencing, and a protein interaction network was constructed using STRING to explore the possible mechanisms. Next, the targeting relationship between miR-653-3p and IGF1 was determined. NO2-induced migraine was verified by silencing miR-653-3p and IGF1, independently or in combination to regulate the protein kinase B (AKT)/TRPV1 signalling pathway through the miR-653-3p/IGF1 axis. These results indicate that the key molecular mechanism of NO2-induced migraine may be that the miR-653-3p/IGF1 axis regulates the AKT/TRPV1 signalling pathway to induce migraine. The findings of this study will further elucidate the neurotoxic mechanism of NO2-induced migraines and lay a new experimental foundation for implementing migraine-related preventive and therapeutic control measures.

Ambient NO2 exposure induces migraine in rats: Evidence, mechanisms and interventions

Migraine is a complex neurological disorder with a high disability rate. Although the precipitating factors of migraine remain unclear, previous studies suggest that when there is excess nitrogen dioxide (NO₂) pollution in the atmosphere, the medical demand due to migraine attacks increases sharply. However, the main role of NO₂ as a trigger for migraine is not yet well understood. The purpose of this study was to explore the relationship between NO₂ exposure and the occurrence of migraine as well as the possible underlying mechanisms. We first investigated whether repeated short-term NO₂ exposure could induce behavioural and biological migraine phenotypes in rats. Next, capsazepine (CZP) was used to block transient receptor potential cation channel subfamily V member 1 (TRPV1) in vivo, and CZP and vitamin E (VE) were used to verify the role of reactive oxygen species (ROS)-TRPV1 signalling in NO₂-induced migraine in primary trigeminal neurones in vitro. We demonstrated that short-term repeated NO₂ exposure can significantly induce migraine in rats, and its key molecular mechanism may be related to ROS burst and its downstream TRPV1 channel activation. The findings of this study will enhance the understanding of the neurotoxic mechanism of NO₂, provide new clues for identifying the aetiology of migraine, and lay a new experimental basis for implementing migraine-related preventive and therapeutic control measures.

COVID-19 transport restrictions in Ireland: impact on air quality and respiratory hospital admissions

Aim

Exposure to poor air quality is a well-established factor for exacerbation of respiratory system diseases (RSDs); whether air pollutants are a cause of the development of RSD, however, remains unclear. This study aimed to examine the relationship between COVID-19 transport restrictions and hospital admissions because of RSD in Dublin city and county for 2020.

Study design

This was a retrospective population-based cohort.

Methods

Admission data were collected from the Health Service Executive Hospital In-patient Enquiry. Daily count of hospital admissions with Dublin city and county address with primary diagnosis of RSD was performed. The daily air nitrogen dioxide (NO₂) data were obtained from the Environmental Protection Agency (EPA).

Results

During the period of transport restrictions, there was a reduction in the annual mean NO₂ from 25 μg/m³ to 17 μg/m³ (P < 0.001), and decreases in hospital admissions for RSD were observed. Among the 9934 patient episodes included in this study, the mean age at admission was 61.5 years, 57.8% were female (n = 5744), and mean (standard deviation) length of stay was 7.5 (13.52) days.

Conclusion

This study, using routinely gathered data, suggests that decreases in ambient NO₂ as related to COVID-19 transport restrictions were significantly associated with lower asthma and chronic obstructive pulmonary disease admissions.