Phthalate exposure induces cell death and ferroptosis in neonatal microglial cells

Phthalates are the materials used for plasticizing polyvinyl chloride. Di-(2-Ethylhexyl) phthalate (DEHP) is one of the phthalates most frequently used in a wide range of applications, including medical equipment such as endotracheal and feeding tubes, intravenous catheters, central lines, extracorporeal membrane oxygenation sets, total parenteral nutrition bags, blood product sets, and intravenous pump lines, respiratory sets in neonatal intensive care units (NICUs). Studies have shown that phthalates, including DEHP, can cross the placenta and blood-brain barrier, possibly leading to neurodevelopmental impairment in vitro and in vivo. However, the molecular mechanisms affected by phthalate exposure have not been explored in depth. This study aimed to illuminate the effects of DEHP on neuroinflammation at the molecular level using neonatal microglial cells as the model.

Mouse BV-2 neonatal microglia cells were exposed to DEHP under controlled conditions. Cellular toxicity was assessed via a cell viability assay and specific markers were used to evaluate the apoptosis/necrosis, cellular iron content, reactive oxygen species (ROS), and organelle integrity. Proinflammatory proteins were quantified using enzyme-linked immunosorbent assay, while ferroptosis was assessed using a ferroptosis blocker, and affected gene expressions were determined using quantitative reverse-transcriptase real-time polymerase chain reaction (RT-PCR).

The results revealed that high concentrations of DEHP exposure increased toxicity via increased levels of ROS and inflammation. Elevated ROS levels were observed to increase the tendency for mitochondrial-lysosomal disruption, bringing about apoptosis or necrosis. Moreover, iron homeostasis was dysregulated by DEHP, which putatively triggered ferroptosis in a dose-dependent manner.

This study indicates that neonatal exposure to DEHP may be linked to neurodevelopmental impairment via inflammation-related cell death and ferroptosis. The prevalence of DEHP in NICU medical devices raises concerns about potential neurodevelopmental deficits, including disorders like autism and mental retardation. These findings highlight the urgency of addressing DEHP exposure in neonatal care.