[Toxicity of dibutyl phthalate in primary cultured rat hippocampal neurons and the toxicological mechanism].

OBJECTIVE: To investigate the neurotoxicity and toxicological mechanism of dibutyl phthalate (DBP) in primary cultured rat hippocampal neurons. METHODS: Primary rat hippocampal neurons cultured for 4 days were exposed to 1 g/L DBP for 24, 48, or 96 h. Immunofluorescence assay and transmission electron microscopy (TEM) were used to observe the morphological changes of the axons and the ultrastructure of DBP-treated neurons. The action potential (AP) of the hippocampal neurons was measured with patch-clamp electrophysiology. CCK-8 assay was used to detect the viability of the hippocampal neurons, and Western blotting was performed to determine the mRNA and protein expressions of brain-derived neurotrophic factor (BDNF), neuropeptide Y (NPY) and estrogen receptor β (ERβ). High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS) was employed to detect the release of the neurotransmitter GABA. RESULTS: After exposure to DBP for 96 h, the cellular network of the hippocampal neurons became sparse, and the neurons showed significantly decreased axonal length (P < 0.01) and presented with round cell nuclei, chromatin aggregation and cytoplasmic vacuolization. Patch-clamp electrophysiology revealed depolarization drift and increased frequency of discharge in the exposed neurons (P < 0.01). The neurons with DBP exposure for 24, 48 and 96 h all showed significantly decreased cell viability (P < 0.01). DBP exposure for 48 and 96 h significantly lowered the protein expressions of ERβ, BDNF and NPY, and a 96-h exposure significantly reduced the release of the neurotransmitter GABA in the neurons (P < 0.05). CONCLUSIONS: DBP exposure causes morphological and functional damages of primary cultured rat hippocampal neurons. DBP-induced neurotoxicity is probably associated with GABA-mediated blockage of the ERβ-BDNF-NPY signaling communication.