TY - JOUR
T1 - 7,12-Dimethylbenz[a]anthracene exposure induces the DNA repair response in neonatal rat ovaries
AU - Ganesan, Shanthi
AU - Bhattacharya, Poulomi
AU - Keating, Aileen F.
N1 - Funding Information:
The project described was supported by award number R00ES016818 to AFK and by a fellowship from the American Association of University Women to SG. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Environmental Health Sciences or the National Institutes of Health.
PY - 2013/11/1
Y1 - 2013/11/1
N2 - 7,12-Dimethylbenz[a]anthracene (DMBA) destroys ovarian follicles at all stages of development. This study investigated DMBA-induced DNA double strand break (DSB) formation with subsequent activation of the ovarian DNA repair response in models of pre-antral or pre-ovulatory follicle loss. Postnatal day (PND) 4 Fisher 344 (F344) rat ovaries were cultured for 4. days followed by single exposures of vehicle control (1% DMSO) or DMBA (12.5. nM or 75. nM) and maintained in culture for 4 or 8. days. Alternately, PND4 F344 rat ovaries were exposed to 1. μM DMBA at the start of culture for 2. days. Total RNA or protein was isolated, followed by qPCR or Western blotting to quantify mRNA or protein level, respectively. γH2AX and phosphorylated ATM were localized and quantified using immunofluorescence staining. DMBA exposure increased caspase 3 and γH2AX protein. Additionally, DMBA (12.5. nM and 1. μM) increased levels of mRNA encoding Atm, Xrcc6, Brca1 and Rad51. In contrast, Parp1 mRNA was decreased on d4 and increased on d8 of DMBA exposure, while PARP1 protein increased after 8. days of DMBA exposure. Total ATM increased in a concentration-dependent temporal pattern (75. nM d4; 12.5. nM d8), while pATM was localized in large primary and secondary follicles and increased after 8. days of 75. nM DMBA exposure compared to both control and 12.5. nM DMBA. These findings support that, despite some concentration effects, DMBA induces ovarian DNA damage and that DNA repair mechanisms are induced as a potential mechanism to prevent follicle loss.
AB - 7,12-Dimethylbenz[a]anthracene (DMBA) destroys ovarian follicles at all stages of development. This study investigated DMBA-induced DNA double strand break (DSB) formation with subsequent activation of the ovarian DNA repair response in models of pre-antral or pre-ovulatory follicle loss. Postnatal day (PND) 4 Fisher 344 (F344) rat ovaries were cultured for 4. days followed by single exposures of vehicle control (1% DMSO) or DMBA (12.5. nM or 75. nM) and maintained in culture for 4 or 8. days. Alternately, PND4 F344 rat ovaries were exposed to 1. μM DMBA at the start of culture for 2. days. Total RNA or protein was isolated, followed by qPCR or Western blotting to quantify mRNA or protein level, respectively. γH2AX and phosphorylated ATM were localized and quantified using immunofluorescence staining. DMBA exposure increased caspase 3 and γH2AX protein. Additionally, DMBA (12.5. nM and 1. μM) increased levels of mRNA encoding Atm, Xrcc6, Brca1 and Rad51. In contrast, Parp1 mRNA was decreased on d4 and increased on d8 of DMBA exposure, while PARP1 protein increased after 8. days of DMBA exposure. Total ATM increased in a concentration-dependent temporal pattern (75. nM d4; 12.5. nM d8), while pATM was localized in large primary and secondary follicles and increased after 8. days of 75. nM DMBA exposure compared to both control and 12.5. nM DMBA. These findings support that, despite some concentration effects, DMBA induces ovarian DNA damage and that DNA repair mechanisms are induced as a potential mechanism to prevent follicle loss.
KW - 7,12-Dimethylbenz[a]anthracene
KW - DNA damage
KW - DNA double strand break repair
KW - Ovotoxicity
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U2 - 10.1016/j.taap.2013.08.013
DO - 10.1016/j.taap.2013.08.013
M3 - Article
C2 - 23969067
AN - SCOPUS:84884713620
SN - 0041-008X
VL - 272
SP - 690
EP - 696
JO - Toxicology and Applied Pharmacology
JF - Toxicology and Applied Pharmacology
IS - 3
ER -