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Thakur VS, Liang YW, Lingappan K, Jiang W, Wang L, Barrios R, Zhou G, Guntupalli B, Shivanna B, Maturu P, Welty SE, Moorthy B, Couroucli XI. Increased susceptibility to hyperoxic lung injury and alveolar simplification in newborn rats by prenatal administration of benzo[a]pyrene. Toxicol Lett 2014; 230:322-32. [PMID: 24657529 DOI: 10.1016/j.toxlet.2014.03.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2013] [Revised: 02/11/2014] [Accepted: 03/11/2014] [Indexed: 12/27/2022]
Abstract
Maternal smoking is one of the risk factors for preterm birth and for the development of bronchopulmonary dysplasia (BPD). In this study, we tested the hypothesis that prenatal exposure of rats to benzo[a]pyrene (BP), a component of cigarette smoke, will result in increased susceptibility of newborns to oxygen-mediated lung injury and alveolar simplification, and that cytochrome P450 (CYP)1A and 1B1 enzymes and oxidative stress mechanistically contribute to this phenomenon. Timed pregnant Fisher 344 rats were administered BP (25 mg/kg) or the vehicle corn oil (CO) on gestational days 18, 19 and 20, and newborn rats were either maintained in room air or exposed to hyperoxia (85% O2) for 7 or 14 days. Hyperoxic newborn rats prenatally exposed to the vehicle CO showed lung injury and alveolar simplification, and inflammation, and these effects were potentiated in rats that were prenatally exposed to BP. Prenatal exposure to BP, followed by hyperoxia, also resulted in significant modulation of hepatic and pulmonary cytochrome P450 (CYP)1A and 1B1 enzymes at PND 7-14. These rats displayed significant oxidative stress in lungs at postnatal day (PND) 14, as evidenced by increased levels of the F2-isoprostane 8-iso-PGF2α. Furthermore, these animals showed BP-derived DNA adducts and oxidative DNA adducts in the lung. In conclusion, our results show increased susceptibility of newborns to oxygen-mediated lung injury and alveolar simplification following maternal exposure to BP, and our results suggest that modulation of CYP1A/1B1 enzymes, increases in oxidative stress, and BP-DNA adducts contributed to this phenomenon.
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Affiliation(s)
- Vijay S Thakur
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Yanhong W Liang
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Krithika Lingappan
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Weiwu Jiang
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Lihua Wang
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Roberto Barrios
- Department of Pathology and Genomic Medicine, The Methodist Hospital Physician Organization, 6565 Fannin Street, Suite M227, Houston, TX 77030, USA
| | - Guodong Zhou
- Institute of Biotechnology, Texas A&M University Health Science Center, Houston, TX 77030, USA
| | - Bharath Guntupalli
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Binoy Shivanna
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Paramahamsa Maturu
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Stephen E Welty
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Bhagavatula Moorthy
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA
| | - Xanthi I Couroucli
- Department of Pediatrics, Section of Neonatology, Texas Children's Hospital, Baylor College of Medicine, 1102 Bates Avenue, MC: FC530.01, Houston, TX 77030, USA.
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Zaccaria KJ, McClure PR. Using Immunotoxicity Information to Improve Cancer Risk Assessment for Polycyclic Aromatic Hydrocarbon Mixtures. Int J Toxicol 2013; 32:236-50. [DOI: 10.1177/1091581813492829] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Estimating cancer risk from environmental mixtures containing polycyclic aromatic hydrocarbons (PAHs) is challenging. Ideally, each mixture would undergo toxicity testing to derive a cancer slope factor (CSF) for use in site-specific cancer risk assessments. However, this whole mixture approach is extremely costly in terms of finances, time, and animal usage. Alternatively, if an untested mixture is “sufficiently similar” to a well-characterized mixture with a CSF, the “surrogate” CSF can be used in risk assessments. We propose that similarity between 2 mixtures could be established using an in vitro battery of genotoxic and nongenotoxic tests. An observed association between carcinogenicity and immunosuppression of PAHs suggests that the addition of immune suppression assays may improve this battery. First, using published studies of benzo[a]pyrene (BaP) and other PAHs, we demonstrated a correlation between the derived immune suppression relative potency factors (RPFs) for 9 PAHs and their respective cancer RPFs, confirming observations published previously. Second, we constructed an integrated knowledge map for immune suppression by BaP based on the available mechanistic information. The map illustrates the mechanistic complexities involved in BaP immunosuppression, suggesting that multiple in vitro tests of immune suppression involving different processes, cell types, and tissues will have greater predictive value for immune suppression in vivo than a single test. Based on these observations, research strategies are recommended to validate a battery of in vitro immune suppression tests that, along with tests for genotoxic and other nongenotoxic modes of cancer action, could be used to establish “sufficient similarity” of 2 mixtures for site-specific cancer risk assessments.
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Affiliation(s)
| | - Peter R. McClure
- SRC, Inc, Defense and Environmental Solutions, North Syracuse, NY, USA
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