OBJECTIVES: Exposure to rare earth elements (REEs) has been linked to various systemic diseases, but their impact on the offspring blood-brain barrier (BBB) via the gut-brain axis remains unclear. This study aims to investigate the effects of maternal exposure to neodymium oxide (Nd₂O₃) on the BBB integrity of offspring rats, and to evaluate the potential protective role of bifidobacterium tetrad viable tablets (BTVT) against Nd₂O₃-induced intestinal and BBB damage. METHODS: Healthy adult SD rats were mated at a 1:1 male-to-female ratio, with the day of vaginal plug detection marked as gestational day 0. A total of 60 pregnant rats were randomly assigned to the following groups: Control, 50 mg/(kg·d) Nd₂O₃, 100 mg/(kg·d) Nd₂O₃, 200 mg/(kg·d) Nd₂O₃, and 200 mg/(kg·d) Nd₂O₃ + BTVT group. Treatments were administered by daily oral gavage throughout pregnancy and lactation. On postnatal day 21 (weaning), offspring feces, brain, and colon tissues were collected. Hematoxylin and eosin (HE) staining was used to assess structural changes in brain and intestinal tissues. Short-chain fatty acids (SCFAs) in feces were quantified by gas chromatography-mass spectrometry (GC-MS). Evans Blue (EB) dye extravasation assessed BBB permeability. Gene and protein expression levels of tight junction proteins occludin and zonula occludens-1 (ZO-1) were measured by reverse transcription PCR (RT-PCR) and Western blotting (WB), respectively. Neodymium levels in brain tissue were determined via inductively coupled plasma mass spectrometry (ICP-MS). RESULTS: HE staining revealed that maternal Nd₂O₃ exposure caused mucosal edema, increased submucosal spacing, and lymphocyte infiltration in offspring colon, as well as neuronal degeneration and vacuolization in brain tissue. BTVT intervention alleviated these changes. GC-MS analysis showed that levels of acetic acid, propionic acid, butyric acid, and isobutyric acid significantly decreased, while valeric acid and isovaleric acid increased in offspring of Nd₂O₃-exposed mothers (P<0.05). BTVT significantly restored levels of acetic, propionic, and isobutyric acids and reduced valeric acid content (P<0.05). EB permeability was significantly elevated in Nd₂O₃-exposed offspring brains (P<0.05), but reduced with BTVT treatment (P<0.05). RT-PCR and WB showed downregulation of occludin and ZO-1 expression following Nd₂O₃ exposure (P<0.05), which was reversed by BTVT (P<0.05). ICP-MS results indicated significantly increased brain neodymium levels in offspring from all Nd₂O₃-exposed groups (P<0.05), while BTVT significantly reduced neodymium accumulation compared to the 200 mg/(kg·d) Nd₂O₃ group (P<0.05). CONCLUSIONS Maternal exposure to Nd₂O₃ during pregnancy and lactation disrupts intestinal health and BBB integrity in offspring, elevates brain neodymium accumulation, and induces neuronal degeneration. BTVT effectively mitigates Nd₂O₃-induced intestinal and BBB damage in offspring, potentially through modulation of the gut-brain axis.
Animals ; Female ; Blood-Brain Barrier/pathology* ; Pregnancy ; Rats, Sprague-Dawley ; Rats ; Male ; Neodymium/toxicity* ; Prenatal Exposure Delayed Effects/prevention & control* ; Lactation ; Maternal Exposure/adverse effects* ; Brain

We investigated whether Nd2O3 treatment results in cytotoxicity and other underlying effects in rat NR8383 alveolar macrophages. Cell viability assessed by the MTT assay revealed that Nd2O3 was toxic in a dose-dependent manner, but not in a time-dependent manner. An ELISA analysis indicated that exposure to Nd2O3 caused cell damage and enhanced synthesis and release of inflammatory chemokines. A Western blot analysis showed that protein expression levels of caspase-3, nuclear factor-κB (NF-κB) and its inhibitor IκB increased significantly in response to Nd2O3 treatment. Both NF-κB and caspase-3 signaling were activated, suggesting that both pathways are involved in Nd2O3 cytotoxicity.
Animals ; Caspase 3 ; metabolism ; Cell Line ; Macrophages, Alveolar ; drug effects ; enzymology ; NF-kappa B ; metabolism ; Neodymium ; toxicity ; Oxides ; toxicity ; Rats ; Toxicity Tests