mRNA expression in lung tissue

Previous studies have reported sex differences in the incidence, prognosis and control of respiratory diseases and lung immunity. However, the role of sex hormones in the inflammatory response, and the mechanisms involved are unknown. Here, we explored whether variations in circulating hormone levels in the mouse estrous cycle could alter the inflammatory response to air pollutants such as ozone. To test this, female mice of the C57BL/6 background were exposed to 2ppm of ozone or filtered air (control) for 3 hours at different stages of the estrous cycle. Following exposure, lungs were harvested and total RNA was extracted. We used Inflammatory Response and Autoimmunity PCR Arrays to study differences in gene expression across the estrous cycle. Our results identified differentially expressed mRNA signatures in the lungs of females exposed to ozone at different stages of the estrous cycle. In addition, in silico pathway analyses discovered differences in mRNA expression and predicted regulatory networks in females exposed to ozone at different estrous cycle stages. These results indicate that the effects of ozone exposure in the female lung are affected by hormonal status. Female C57BL/6 mice of 8 weeks of age were exposed to 2ppm ozone (O3) or filtered air (FA) for 3 hours at different stages of the estrous cycle: Metestrus (M), Diestrus (D), proestrus (P), estrus (E). Total RNA was extracted from whole lung homogenates and PCR arrays were used to determine the expression of 84 mRNAs associated with inflammation and immunity (3-6 animals per group).