Maternal exposure to polycyclic aromatic hydrocarbons diminishes murine ovarian reserve via induction of Harakiri
J. Clin. Invest. Andrea Jurisicova, et al. 117:3971 doi:10.1172/JCI28493 [Go to this article.]

Figure 4
Regulation of Hrk expression in Bax-deficient mouse ovaries and in human ovarian cortical strips. (A) Induction of Bax expression in ovaries of 3-week-old littermates exposed to vehicle only or PAH treatment prior to pregnancy and during lactation. While Bax induction was evident in both primordial and primary follicles (arrows) in wild-type ovaries upon PAH exposure, induction was not evident in the Hrk-deficient females. Note that larger follicles with several layers of granulosa cells also abundantly expressed Bax. However, this expression was regulated by gonadotropins and was independent of PAH treatment. Images are representative results of at least 3 different animals/genotype/treatment. (B) Hrk-deficient neonatal ovaries failed to upregulate Bax transcript expression in response to in vitro exposure to PAHs over a 24-hour period. The expression data are shown as fold change in PAH-treated versus vehicle-treated ovary from the same female (mean ± SEM) and were obtained from 7 sets of independent ovaries per treatment/genotype. PAH induced a significantly different response between wild-type and Hrk-deficient ovaries (P = 0.035). (C) PAHs induce Hrk expression in human primary (set 1) and primordial (set 2) follicles in ex vivo model. Representative images of immunohistochemical analysis of Hrk protein levels, evidenced by brown staining, in follicles of ovarian grafts 48 hours after exposure to vehicle, PAH, or PAH and resveratrol. Follicles exposed to PAHs have abnormal shrinking morphology typical of degenerating apoptotic follicles. Induction of Hrk was observed primarily in the granulosa cells (arrows) as well as in the surrounding stroma and was almost completely abolished in both cell types by cotreatment with resveratrol (magnification, ×1,000). Data shown are representative results observed from 2 independent sets of experiments using tissues from 2 different patients. No immunoreactivity was observed when primary antibody was omitted (data not shown).