Estrogen promotes ethanol-induced CYP2E1 upregulation and Period 2 downregulation, leading to worsened cardiac ferroptosis and dysfunction in female rats.

The induction of cytochrome P450 2E1 (CYP2E1) and heme oxygenase-1 (HO-1) and reduction in their reciprocally regulated circadian clock protein Period 2 (Per2) contribute to ethanol (EtOH)-induced cardiac dysfunction in male rats. However, it remains unknown if these responses, which lead to ferroptosis (iron-dependent cell death), are sex-specific. These translational studies are crucial because women and female rats are more susceptible to EtOH-induced cardiac dysfunction, despite the biological estrogen (E2)-dependent upregulation of Per2 and dampening of ferroptosis in the heart. We hypothesize that CYP2E1 induction transforms E2 into a proinflammatory hormone that paradoxically suppresses Per2 and exacerbates ferroptosis, resulting in worsened EtOH-induced cardiac dysfunction in females. Female Sprague-Dawley rats (n = 6/group) underwent bilateral ovariectomy (OVX) and were assigned to OVX control, OVX + EtOH (5% w/v liquid diet), and OVX + EtOH + E2 (20 μg/kg) for 8 weeks. Cardiac function was assessed by echocardiography, followed by biochemical and molecular analyses. Compared to the OVX + vehicle or OVX + EtOH groups, the OVX + EtOH + E2 group exhibited significantly impaired cardiac function (reduced ejection fraction, fractional shortening). These functional alterations were linked to enhanced CYP2E1 activity and reduced Per2 expression. Further, histological analyses revealed myocardial architectural disruption and collagen deposition in the OVX + EtOH + E2 group. Together, these results suggest that EtOH alters E2 signaling, contributing to oxidative stress and ferroptosis-induced cardiac dysfunction in females.