Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Aug 30;183(1):170-183.
doi: 10.1093/toxsci/kfab081.

Sex Differences in Pulmonary Eicosanoids and Specialized Pro-Resolving Mediators in Response to Ozone Exposure

Michael J Yaeger  1 , Sky W Reece  2 , Brita Kilburg-Basnyat  2 , Miles X Hodge  2 , Anandita Pal  3 , Katelyn Dunigan-Russell  1 , Bin Luo  2 , Dorothy J You  4 , James C Bonner  4 , Espen E Spangenburg  5 , Debra Tokarz  6 , Johanna Hannan  5 , Michael Armstrong  7 , Jonathan Manke  7 , Nichole Reisdorph  7 , Robert M Tighe  8 , S Raza Shaikh  3 , Kymberly M Gowdy  1
Affiliations

Sex Differences in Pulmonary Eicosanoids and Specialized Pro-Resolving Mediators in Response to Ozone Exposure

Michael J Yaeger et al. Toxicol Sci. .

Abstract

Ozone (O3) is a criteria air pollutant known to increase the morbidity and mortality of cardiopulmonary diseases. This occurs through a pulmonary inflammatory response characterized by increased recruitment of immune cells into the airspace, pro-inflammatory cytokines, and pro-inflammatory lipid mediators. Recent evidence has demonstrated sex-dependent differences in the O3-induced pulmonary inflammatory response. However, it is unknown if this dimorphic response is evident in pulmonary lipid mediator metabolism. We hypothesized that there are sex-dependent differences in lipid mediator production following acute O3 exposure. Male and female C57BL/6J mice were exposed to 1 part per million O3 for 3 h and were necropsied at 6 or 24 h following exposure. Lung lavage was collected for cell differential and total protein analysis, and lung tissue was collected for mRNA analysis, metabololipidomics, and immunohistochemistry. Compared with males, O3-exposed female mice had increases in airspace neutrophilia, neutrophil chemokine mRNA, pro-inflammatory eicosanoids such as prostaglandin E2, and specialized pro-resolving mediators (SPMs), such as resolvin D5 in lung tissue. Likewise, precursor fatty acids (arachidonic and docosahexaenoic acid; DHA) were increased in female lung tissue following O3 exposure compared with males. Experiments with ovariectomized females revealed that loss of ovarian hormones exacerbates pulmonary inflammation and injury. However, eicosanoid and SPM production were not altered by ovariectomy despite depleted pulmonary DHA concentrations. Taken together, these data indicate that O3 drives an increased pulmonary inflammatory and bioactive lipid mediator response in females. Furthermore, ovariectomy increases susceptibility to O3-induced pulmonary inflammation and injury, as well as decreases pulmonary DHA concentrations.

Keywords: air pollution; inflammation; lipids; lung; sex differences.

PubMed Disclaimer

Figures

Figure 1.
Figure 1.
Females have an increased pulmonary inflammatory response to O3 but no differences in lung injury. Female and male mice were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied 6 or 24 h following exposure. Bronchoalveolar lavage (BAL) was analyzed for (A) cell differentials 6 h post exposure, (B) cell differentials 24 h post exposure (n = 9–15 per group), and lung tissue was harvested and analyzed for mRNA expression of TNF-α, IL-6, IL-1β, CXCL1, and CXCL2 at (C) 6 h post exposure, and (D) 24 h post exposure. The dashed line at y = 1 represents the FA value that fold change expression is normalized to. BAL was also analyzed for (E) total protein. #p < .05, ##p < .01, ###p < .001 compared with same sex FA group. *p < .05, **p < .01, ***p < .001, ****p < .0001 compared between males and females in the same exposure group (either FA or O3); n = 6–15 per group for BAL analysis. n = 5–15 per group for mRNA expression analysis. ND = not detectable.
Figure 2.
Figure 2.
Pulmonary levels of pro-inflammatory lipid mediators are augmented in females compared with males following O3 exposure. Male and female mice were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied at 6 or 24 h following exposure. (A) Lung tissue was analyzed for the listed lipid mediators 6 and 24 h post exposure by LC/MS-MS. Selected lipids were graphed over time: (B) 15S-HETE, (C) PGF2α, (D) 12S-HETE, (E) PGE2, (F) 13-HODE, and (G) 9-HODE. *p < .05,****p < .0001; n = 6 per group.
Figure 3.
Figure 3.
O3 exposure increases pulmonary levels of DHA-derived SPMs in females but not males. Female and male mice were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied at 6 or 24 h following exposure. Lung tissue was analyzed for (A) RvD5, (B) PDX, (C) 17(S)-HDHA, and (D) 14(S)-HDHA, at 6 and 24 h post exposure. *p < .05, **p < .01, ****p < .0001, ND = not detectable; n = 6 per group.
Figure 4.
Figure 4.
Sex does not alter the pulmonary expression of lipid metabolizing enzymes after O3 exposure. Female and male mice were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied at 6 or 24 h following exposure. Lung tissue was processed for immunohistochemistry and stained for COX-2 at (A) 6 h post exposure, and (B) 24 h post exposure. Slides were graded by a veterinary pathologist according to the grading scheme described in Supplementary Table 3. RNA from lung tissue was harvested and analyzed for mRNA expression of 5-LOX and 12/15-LOX at (C) 6 h post exposure, and (D) 24 h post exposure. The dashed line at y = 1 represents the FA value that fold change expression is normalized to. n = 3–6 per group.
Figure 5.
Figure 5.
DHA and AA accumulate in female lungs more than male lungs following O3 exposure. Mice were exposed to 1 ppm O3 for 3 h or filtered air (FA) and necropsied at 24 h following exposure. Whole lung tissue homogenate was analyzed for (A) docosahexaenoic acid (DHA) and (B) arachidonic acid (AA). Lung tissue from different animals under the same experimental conditions was harvested and analyzed for mRNA expression of (C) ELOVL2. The dashed line at y = 1 represents the FA value that fold change expression is normalized to. #p < .05, compared with same sex FA group. *p < .05, ***p < .001, ****p < .0001; n = 6 per group.
Figure 6.
Figure 6.
Ovariectomy increases pulmonary macrophage influx and injury following O3 exposure. Female mice that underwent either sham surgery (Sham) or ovariectomy (OVX) were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied at 24 h following exposure. BAL was collected and analyzed for (A) cell differential counts, and (B) total protein concentration at 24 h post exposure. #p < .05, ##p < .01, ###p < .001 compared with same sex FA group. *p < .05, **p < .01 compared between males and females; n = 6 per group.
Figure 7.
Figure 7.
The lung lipid mediator profile following O3 exposure is not altered by ovariectomy. Female mice that underwent sham surgery (Sham) or ovariectomy (OVX) were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied at 24 h following exposure. Lung tissue was analyzed for the listed lipid mediators by LC-MS/MS 24 h post exposure. n = 5 per group.
Figure 8.
Figure 8.
Ovariectomy does not alter pulmonary SPM production following O3 exposure. Female mice that underwent sham surgery (Sham) or ovariectomy (OVX) were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied at 24 h following exposure. Lungs were collected and analyzed for (A) RvD5 (B) PDX, (C) 17(S)-HDHA, and (D) 14(S)-HDHA, at 24 h post exposure. n = 3–5 per group.
Figure 9.
Figure 9.
Ovariectomy decreased pulmonary DHA levels following O3 exposure. Female mice that underwent sham surgery (Sham) or ovariectomy (OVX) were exposed to 1 ppm O3 or filtered air (FA) for 3 h and necropsied at 24 h following exposure. Lung tissue was collected and analyzed for DHA levels 24 h post exposure. *p < .05, **p < .01 compared between males and females; n = 3–5 per group.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Alfaro M. F., Walby W. F., Adams W. C., Schelegle E. S. (2007). Breath condensate levels of 8-isoprostane and leukotriene B4 after ozone inhalation are greater in sensitive versus nonsensitive subjects. Exp. Lung Res. 33, 115–133. - PubMed
    1. Aoki T., Narumiya S. (2012). Prostaglandins and chronic inflammation. Trends Pharmacol. Sci. 33, 304–311. - PubMed
    1. Armstrong M., Manke J., Nkrumah-Elie Y., Shaikh S. R., Reisdorph N. (2020). Improved quantification of lipid mediators in plasma and tissues by liquid chromatography tandem mass spectrometry demonstrates mouse strain specific differences. Prostaglandins Other Lipid Mediat. 151, 106483. - PubMed
    1. Bakewell L., Burdge G. C., Calder P. C. (2006). Polyunsaturated fatty acid concentrations in young men and women consuming their habitual diets. Br. J. Nutr. 96, 93–99. - PubMed
    1. Barden A. E., Moghaddami M., Mas E., Phillips M., Cleland L. G., Mori T. A. (2016). Specialised pro-resolving mediators of inflammation in inflammatory arthritis. Prostaglandins Leukot Essent. Fatty Acids 107, 24–29. - PubMed

Publication types