Experimental study on DEHP affect the neurodevelopment through interfering with placental thyroid hormones transport / 中华劳动卫生职业病杂志

Objective@#The present study was represented by di-(2-ethylhexyl) phthalate (DEHP), to explore the role of thyroid hormones (THs) disruption in the connection of placenta and neurodevelopmental toxicity.@*Methods@#During fetal mice neural tube closed (pregnancy 9.5 days, E9.5d) to begin synthesis of THs (E15.5 d), all pregnant mice were administered with different concentration of DEHP (0、10、50、200 mg/kg) by gavage once a day(10 mice per group). All pregnant mice were conducted with BrdU administration in E14d by subcutaneous injection. Seven pregnant mice from each group were scarified after anesthesia in E15.5 d, serum and amniotic fluid were collected to determinate the levels of THs(T3, T4, FT3 and FT4) by the automatic biochemical analyzer, detecting fetal mice placental protein expression of monocarboxylate transporter 8 (MCT8), organic anion transporting polypeptide 1C1 (OATP1C1) and deiodinaseⅡ&Ⅲ (DIO2, DIO3) by Western blot. Each group of the remaining three pregnant mices were killed after anesthesia in E18d, take the male fetal brain, BrdU immunohistochemistry was used to detect the proliferation and migration of fetal brain cortical neurons.@*Results@#There was no abnormalities in diet, water intake, body weight and general activity of pregnant mice in each treatment group, and there were no difference in the general physiolo. Results There was no abnormalities in diet, water intake, body weight and general activity of pregnant mice in each treatment group, and there were no difference in the general physiological development status of body weight, brain weight, brain body ratio between the mice of each group. There was no statistically significant differences in serum T3, T4, FT3, FT4 and amniotic fluid FT4 in pregnant mice of each group (P>0.05), Compared with the control group, the FT3 levels in the amniotic fluid of the DEHP 50 and 200 mg/kg groups were significantly decreased(P<0.05). Compared with the control group, the placental MCT8 and DIO2 protein levels of male fetal mice in the DEHP 50 and 200 mg/kg group decreased, and the level of OATP1C1 protein in 200 mg/kg group decreased(P<0.05), and there was no statistically significant difference in DIO3 protein levels among all groups (P>0.05). Compared with the control group, the number of BrdU positive cells in the cerebral cortex of male mice in DEHP 200 mg/kg group decreased, 56.5% was distributed in VZ-SVZ layer, and the percentage of BrdU positive cells in the IZ layer of 50 mg/kg group increased (P<0.05).@*Conclusion@#DEHP 50, 200 mg/kg may affect the proliferation and migration of neural cells in the developing brain, which may be related to its interference with thyroid hormone by placental transport.

Effects of developmental exposure to DEHP on learning and memory of mice / 中华劳动卫生职业病杂志

Objective@#To investigate the effects of developmental exposure to DEHP on learning and memory of mice.@*Methods@#Male littermates of ICR mice randomly assigned to five experimental groups (n=14 for each condition) on PND4 to receive distilled water, vehicle and 10, 50 and 200 mg/ (kg·d) DEHP from PND5 to PND38 by gavage, weighing and recording body weight of mice. Open field task were conducted on PND 26 and Morris water maze task were begun from PND30 to PND 37 to evaluate spontaneous exploration activity and emotion, spatial learning and memory performance of pubertal mice, respectively. On PND39, all animals were killed and hippocampi were isolated on ice, then total proteins of hippocampus were extracted, followed by determining the expression of PSD95 and synapsin I by western blotting.@*Results@#200 mg/ (kg·d) DEHP significantly reduced the growth of body weight of mice and the time staying in the central area in open field, prolonged the time searching the hidden platform in Morris water maze (P<0.05) . 50 mg/ (kg·d) DEHP didn’t change the growth of body weight and the emotion (P>0.05) , but reduced the percent of time and distance in the target quadrant during the probe trial of mice in Morris water maze (P<0.05) . The results of western blotting showed that DEHP significantly reduced the expression of PSD95 in hippocampus of mice with all dose groups (P<0.01) , but only 200 mg/ (kg·d) DEHP reduced the expression of synapsin I (P<0.05) .@*Conclusion@#Developmental exposure to DEHP can damage the development of synapse in hippocampus, adversely impacting spatial memory performance of mice at a dose that are insufficient to significantly influence the general development and result in anxiety.

Research of λ-cyhalothrin affect synaptic development in hippocampus by interfering with estrogen action / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effects of λ-cyhalothrin on hippocampus by interfering with estrogen.</p><p><b>METHODS</b>The healthy female ICR mice of postnatal 28 days were random divided into 12 groups, 4 of those were sham-operation include control, λ-cyhalothrin (LCT, 3.0 µg/g), Letrozole (Let, 1.0 µg/g), and LCT (3.0 µg/g)+Let (1.0 µg/g); and the last 8 were ovariectomized include OVX, Estradiol (E2, 10.0 µg/g), LCT, Let, E2+LCT, E2+Let, LCT+Let, E2+LCT+Let. 10 mice in every group received drugs by intraperitoneal injection for 2 days. Then half of every group initiate the ethological test (open field test and Morris water maze) 24 h later. The last half animals were sacrificed to made frozen section for immunofluorescent assay of postsynaptic density protein 95 (PSD95).</p><p><b>RESULTS</b>In ethological test, campared with Sham, OVX can lengthen incubation period in the first grid and to get on the platform (P < 0.05); campared with OVX, OVX+E2 can increase the total numbers of through grid and shorten the incubation period to get on the platform (P < 0.05); campared with OVX+E2, OVX+E2+LCT can reduce the number of grid and standing, lengthen incubation period to the platform (P < 0.05); campared with Sham, Sham+LCT can lengthen incubation period to the platform of Sham mice (P < 0.05), but campared with OVX, OVX+LCT can shoten incubation period in the first grid and to get on the platform in OVX mice (P < 0.05); campared with Sham+Let, Sham+LCT+Let can lengthen incubation period in the first grid, reduce the the number of grid and standing (P < 0.05). In the Immunohistochemical fluorescence experiment we find that, campared with Sham, OVX can reduce the expression of PSD95 in CA1,CA3 and DG (P < 0.05); however campared with OVX, E2 or LCT can both inhibit the effect of OVX (P < 0.05); campared with Sham, Sham+LCT can reduce the expression of PSD95, the same result when OVX+E2+LCT campared with OVX+E2 (P < 0.05); campared with OVX+E2+Let, OVX+E2+LCT+Let can reduce the expression of PSD95 in CA3 (P < 0.05); campared with OVX+Let, OVX+LCT+Let can increase the expression of PSD95 in DG (P < 0.05).</p><p><b>CONCLUSIONS</b>When few estrogen exist in the body, LCT can show estrogen-like action to promote hippocampal synaptic development; but when circulating estrogen exist, LCT can inhibit synaptic development by interfering estrogen.</p>

Correlation between the estrogen replacement therapy and the prevalence of female with Alzheimer's dis-ease:a meta-analysis / 中国神经精神疾病杂志

Objective To investigate the relationship between estrogen replacement therapy and female patients with Alzheimer's risk. Methods We searched the PubMed, Springer, CBM, CNKI, VIP database for studies on the es-trogen replacement therapy and women with Alzheimer's disease, retrieval time from database to 2012 December. We evaluated the methodological quality of the included studies, used RevMan 5.0 software to analyze the extracted data. Results We found seven case-control studies which included 1392 patients and 2719 controls. The meta analysis re-sults show that the proportion of estrogen replacement therapy in AD group is significantly lower than that of the con-trol group, the difference has statistically significant [OR=0.68, 95%CI(0.50,0.90), P=0.01]. Conclusions estrogen re-placement therapy has effects on female patients with Alzheimer's disease, and is a protective factor.

Research of fenvalerate induced neurodevelopmental toxicity by interfering with the action of estrogen / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the estrogen interference property of fenvalerate in neurodevelopmental toxicity.</p><p><b>METHODS</b>Thirty 4-week-old healthy female ICR mice were randomly divided into 6 groups: sham operation group, ovariectomized control group, ovariectomized with estrogen (10 µg/g) group, ovariectomized with fenvalerate (5 µg/g) group, sham operation with fenvalerate group, and ovariectomized with estrogen and fenvalerate group, with 5 mice in each group. Fenvalerate was injected intraperitoneally once a day for 7 consecutive days. Mice were sacrificed at 24 h after the last exposure to separate the hippocampus. Immunofluorescence was used to detect neuron marker (NeuN) and astrocyte marker (GFAP) in hippocampal CA1, CA3, and DG regions.</p><p><b>RESULTS</b>Compared with the sham operation group (numbers of NeuN-positive cells: CA1 (54.00±1.73), CA3 (59.00 ± 1.73), DG (100.00 ± 4.58)), the sham operation with fenvalerate group (CA1 (37.67 ± 2.08), CA3 (41.33 ± 1.15), DG (80.67±0.58)) and ovariectomized control group (CA1 (44.00 ± 3.00), CA3 (51.00 ± 3.00), DG (83.00 ± 1.72)) showed significant decreases in number of neurons (NeuN-positive cells) in the hippocampus (P < 0.05). Compared with the ovariectomized control group, the ovariectomized with fenvalerate group (CA1 (47.67 ± 3.21), CA3 (49.00 ± 1.73), DG (87.33 ± 4.04)) showed no significant change in number of hippocampal NeuN-positive cells. Compared with the ovariectomized with fenvalerate group (CA1 (47.67 ± 3.21), DG (87.33 ± 4.04)), the sham operation with fenvalerate group and ovariectomized with estrogen and fenvalerate group (CA1 (40.00 ± 1.00), DG (78.67 ± 2.31)) experienced significant decreases in NeuN-positive cells (P < 0.05). Compared with the sham operation group (CA3 (11.00 ± 1.12), DG (10.67 ± 1.15)), the sham operation with fenvalerate group (CA3 (18.67 ± 2.07), DG (16.33 ± 1.53)) showed significant increase in number of astrocytes (GFAP-positive) cells (P < 0.05). Compared with the sham operation with fenvalerate group, the ovariectomized with fenvalerate group (CA3 (12.00 ± 1.00), DG (11.68 ± 1.16)) showed significant decrease in GFAP-positive cells (P < 0.05). Compared with the ovariectomized with fenvalerate group, the sham operation with fenvalerate group and ovariectomized with estrogen and fenvalerate group (CA3 (16.67 ± 2.13), DG (15.38 ± 1.42)) showed significant increases in GFAP-positive cells (P < 0.05).</p><p><b>CONCLUSION</b>The interference with circulating estrogen is an important mechanism underlying the neurodevelopmental toxicity of fenvalerate.</p>

Research of fenvalerate induce hippocampal neurons injury through interfering with estrogen action / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate whether fenvalerate can induce mouse hippocampal nerve cell damage by interfering with estrogen (E2) effect.</p><p><b>METHODS</b>Hippocampus were dissected and cultured from Embryo 18 d ICR mice, the cells were cultured for 7 days. Fenvalerate (FEN, 0, 1, 10, 50 µg/ml), FEN (10, 50 µg/ml) and estrogen receptor antagonist ICI 182, 780 (1 µmol/L), FEN (0, 10, 50 µg/ml) and E2 (10 nmol/L) were applied to the cultured cells for 48h. Immunocytochemically stained with neurons and astrocytes to evaluate the levels respectively, and the growth of neurite. Result 1µg/ml FEN have no effect on neurons, neurites and protoplasmic astrocytes, 10 and 50 µg/ml FEN can significantly decrease the neuron viability and the length of neurite as well as increase the level of protoplasmic astrocytes (P < 0.05 vs. control group). ICI 182, 780 alone have no effect on neurons, neurites and protoplasmic astrocytes; ICI+10 µg/ml FEN significantly increase the cell viability and extend neurite length as well as decrease protoplasmic astrocytes (P < 0.05 vs. 10 µg/ml FEN alone group); ICI+50 µg/ml FEN significantly increase the cell viability and decrease protoplasmic astrocytes (P < 0.05 vs. 50 µg/ml FEN alone group). E2 alone have no effect on protoplasmic astrocytes, while can promote neuronal survival and neurite growth; E2+10 µg/ml FEN and E2+50 µg/ml FEN significantly decrease neuronal survival and neurite growth, as well as increase protoplasmic astrocytes (P < 0.05 vs. E2 alone group).</p><p><b>CONCLUSION</b>Fenvalerate can induce the loss of hippocampal neurons through disrupting estrogen nuclear receptor signaling, and inhibit the length of neurite through disrupting estrogen nuclear receptor and membrane receptor signaling. The effect of estrogen disruption play an important role in developmental neurotoxicity by fenvalerate.</p>

Effects of early postnatal exposure to m-tolyl methylcarbamate on spatial learning and memory ability of mice / 中华疾病控制杂志

Objective To observe the effects of early postnatal exposure to low-dose m-tolyl methylcarbamate(MTMC) on neurobehavior and spatial learning and memory ability in adolescent and early adult mice,and to dertermine when to affect this ability.Methods ICR mice pups randomly divided into 5 groups received intraperitoneal injections(i.p.) of different doses of MTMC(5 mg?kg-1,0.5 mg?kg-1,0.05 mg?kg-1),DMSO solution and normal saline respectively every other day during postnatal days(PND) 3～13.The general physiological condition and neural development of mice during experiment were evaluated,and a battery of tasks,i.e.hole-board test,beam walking,open field,Morris water maze(MWM),was used to assess their neurobehavior and spatial learning and memory ability in different time.Results Scores were negatively correlated to the doses of MTMC by Spearman rank correlation analysis in beam walking on PND60(rs=-0.418,P