The Uptake and Distribution Evidence of Nano- and Microplastics in vivo after a Single High Dose of Oral Exposure / 生物医学与环境科学（英文）

OBJECTIVE@#Tissue uptake and distribution of nano-/microplastics was studied at a single high dose by gavage in vivo.@*METHODS@#Fluorescent microspheres (100 nm, 3 μm, and 10 μm) were given once at a dose of 200 mg/(kg∙body weight). The fluorescence intensity (FI) in observed organs was measured using the IVIS Spectrum at 0.5, 1, 2, and 4 h after administration. Histopathology was performed to corroborate these findings.@*RESULTS@#In the 100 nm group, the FI of the stomach and small intestine were highest at 0.5 h, and the FI of the large intestine, excrement, lung, kidney, liver, and skeletal muscles were highest at 4 h compared with the control group ( P < 0.05). In the 3 μm group, the FI only increased in the lung at 2 h ( P < 0.05). In the 10 μm group, the FI increased in the large intestine and excrement at 2 h, and in the kidney at 4 h ( P < 0.05). The presence of nano-/microplastics in tissues was further verified by histopathology. The peak time of nanoplastic absorption in blood was confirmed.@*CONCLUSION@#Nanoplastics translocated rapidly to observed organs/tissues through blood circulation; however, only small amounts of MPs could penetrate the organs.

The expression changes of N-methyl-D-aspartic acid receptor in hippocampus of offspring from female rats exposed to aluminum in the pregnancy and lactation / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effects of aluminum on learning and memory and the expression of N-methyl-D-aspartic acid receptor (NMDAR) of hippocampus in offspring from female rats exposed to Al in the pregnancy or lactation, and to explore the mechanism of toxic effects of Al on central nervous system (CNS) during development.</p><p><b>METHODS</b>The pregnant Wistar rats were randomly divided into 3 groups based on their body weight, i.e. control group was exposed to distilled water, low exposure group (0.2%AlCl3) and high exposure group (0.4%AlCl3) were exposed orally to AlCl3 in pregnancy and lactation for 6 weeks, 10 rats each group. Aluminum content in blood and brains was determined by atomic absorption spectrophotometry (AAS). Platform experiment was used to detect the abilities of learning and memory. The expression levels of NMDARs were detected by western blot assay.</p><p><b>RESULTS</b>The Al content in blood and brains of rats in exposure groups increased significantly with Al dose, as compared with the control group (P < 0.05). In platform experiment, the incubation periods of rats in low and high exposure groups were (202.71 ± 81.99) and (19.67 ± 8.44) s respectively, which were significantly lower than that [(300.00 ± 0.00) s] in control group (P < 0.01), but the mistake times of rats in low and high exposure groups were 1.43 ± 0.85 and 2.47 ± 0.99 respectively, which were significantly higher than that (0.00 ± 0.00) in control group (P < 0.01). The Al exposure could change the proportion of NMDAR subtypes, the expression levels of NR1 and NR2B in hippocampus of newborn rats in low and high exposure groups were 25.22 ± 0.68, 81.23 ± 15.37 and 24.75 ± 0.71, 56.63 ± 7.82, respectively, which were significantly lower than those (31.69 ± 3.44, 107.61 ± 9.05) in control group (P < 0.05).</p><p><b>CONCLUSION</b>Aluminum exposure in pregnancy and lactation could reduce the abilities of learning and memory in newborn rats, and change the proportion of NMDAR subtypes. The reduced NR1 and NR2B expression levels may be one of important mechanisms to influence the abilities of learning and memory in offspring.</p>

Effect of aluminum on Ca²+ concentration and expression of phospholipase C and NMDA receptor α genes in hippocampus of weaning rats as well as their neural behavior through subchronic exposure / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To estimate the effect of aluminum on hippocampal intracellular Ca²+ concentration and expression of phospholipase C (PLC) and NMDA receptor α (NMDARα) genes in hippocampus as well as the neural behaviors in weaning rats through subchronic exposure in order to explore the mechanism which aluminum impaired the ability of learning and memory of central nervous system development.</p><p><b>METHODS</b>Weaning Wistar rats were randomly divided into four groups based on their body weight. Aluminium chloride was administered by water at the doses of 0.2%, 0.4% and 0.6% (m/v) for 90 days. Platform experiment was used to detect the activity of learning and memory. Fura-2/AM calcium ions fluorescence indicator was used to measure Ca²+ concentration in hippocampal neurons. Western blot method was used to detect the expressions of PLC and NMDARα genes.</p><p><b>RESULTS</b>The incubation of rats in platform experiment [(232.20 ± 57.45), (35.00 ± 9.37), (16.10 ± 5.57) s] shortened while increase of mistake times (1.10 ± 0.74, 2.20 ± 0.92, 3.40 ± 1.51) was significantly associated with the dose of aluminum (P < 0.01). The Ca(2+) concentration decreased significantly in the rats of aluminum exposed groups (P < 0.01). The expression of PLC and NMDARα in aluminum exposed groups (0.30 ± 0.06, 0.18 ± 0.04, 0.16 ± 0.03; 0.38 ± 0.03, 0.32 ± 0.02, 0.25 ± 0.02) decreased significantly compared with that in the control group (0.47 ± 0.07, 0.48 ± 0.04) (P < 0.01) and there was a dose-effect relationship in the NMDARα expression.</p><p><b>CONCLUSION</b>Subchronic exposure of aluminium could impair the ability of learning and memory in rats during development, inhibit the expression of NMDARα and PLC and reduce Ca²+ concentration, suggesting that the disorder of Ca²+ signaling system might be one of mechanisms of aluminium damaging the ability of learning and memory.</p>