We designed and fabricated a novel high throughput brain-on-chip with three dimensional structure with the aim to simulate the in vivo three-dimensional growth environment for brain tissues. The chip consists of a porous filter and 3D brain cell particles, and is loaded into a conventional 96-well plate for use. The filter and the particle molds were fabricated by using computer modeling, 3D printing of positive mold and agarose-PDMS double reversal mold. The 3D cell particles were made by pouring and solidifying a suspension of mouse embryonic brain cells with sodium alginate into a cell particle mold, and then cutting the resulting hydrogel into pieces. The loaded brain-on-chip was used to determine the neurotoxicity of pesticides. The cell particles were exposed to 0, 10, 30, 50, 100 and 200 µmol/L of chlorpyrifos or imidacloprid, separated conveniently from the medium by removing the porous filter after cultivation. Subsequently, cell proliferation, acetylcholinesterase activity and lactate dehydrogenase release were determined for toxicity evaluation. The embryonic brain cells were able to grow and proliferate normally in the hydrogel particles loaded into the filter in a 96-well plate. Pesticide neurotoxicity test showed that both chlorpyrifos and imidacloprid presented dose-dependent inhibition on cell growth and proliferation. Moreover, the pesticides showed inhibition on acetylcholinesterase activity and increase release of lactate dehydrogenase. However, the effect of imidacloprid was significantly weaker than that of chlorpyrifos. In conclusion, a novel brain-on-chip was developed in this study, which can be used to efficiently assess the drug neurotoxicity, pharmacodynamics, and disease mechanism by combining with a microtiterplate reader.
Animals ; Brain ; Chlorpyrifos/toxicity* ; Culture Media ; Mice ; Oligonucleotide Array Sequence Analysis ; Pesticides/toxicity*

Adsorption ; Adult ; Charcoal ; chemistry ; Chlorpyrifos ; chemistry ; toxicity ; Female ; Hemoperfusion ; Humans ; Insecticides ; chemistry ; toxicity ; Male ; Middle Aged ; Organophosphate Poisoning ; blood ; therapy ; Young Adult

OBJECTIVETo investigate toxicokinetic parameters impacted by hemoperfusion after oral chlorpyrifos exposure, to investigate the adsorption effect of hemoperhusion for chlorpyrifos poisoning.

METHODS12 rabbits were divided into two groups after oral exposure with chlorpyrifos 300 mg/kg body weight. Control group: without hemoperfusion; hemoperfusion group: hemoperfusion starts 0.5 h after chlorpyrifos exposure and lasts for 2h. Blood samples were collected at different times, concentrations of chlorpyrifos were tested by GC, then, toxicokinetic parameterswere calculated and analysis by DAS3.0.

RESULTSIn hemoperfusion group, peak time was (7.19±3.74) h, peak concentrations was (1.37±0.56) mg/L, clearance rate was (13.93±10.27) L/h/kg, apparent volume of distribution was (418.18±147.15) L/kg The difference of these parameter were statistically significant compared with control group (P<0.05).

CONCLUSIONHmoperfusion will decrease the inner exposure and load dose of rabbits with chlorpyrifos poisoning.

Animals ; Chlorpyrifos ; pharmacokinetics ; toxicity ; Hemoperfusion ; Metabolic Clearance Rate ; Rabbits ; Toxicokinetics

OBJECTIVETo establish the method of detecting the concentrations of chlorpyrifos in air of workplace with high performance liquid chromatographic (HPLC).

METHODSAccording to standards of methods for determining the chemical substances in workplace air, chlorpyrifos in the air was collected by silicone tube, then dissolved by acetonitrile and determined by high performance liquid chromatography with UV-detector.

RESULTSThere was a linear relationship within the range of 0 ∼ 10.0 µg/ml, and regression equation was y = 5206.1x - 104.7, correlation coefficient was 0.9999, the detection limit was 0.006 µg/ml. The lowest detected concentration was 0.001 mg/m(3) (sampling volume 4.5 L). The average recoveries was 98.3% ∼ 102.5%. The within-run precision was 1.96% ∼ 4.39%, the between-run precision was 2.76% ∼ 5.87%. The desorption efficiencies were 99.0% ∼ 103.3% and the sampling efficiencies were 94%. The samples in silicone tube could be stored for 15 days at room temperature.

CONCLUSIONThe present method could meet with the requirements of Guide for establishing occupational health standards-Part 4 Determination methods of air chemicals in workplace and be feasible for determination of chlorpyrifos in workplace air.

Air Pollutants, Occupational ; analysis ; Chlorpyrifos ; analysis ; toxicity ; Chromatography, High Pressure Liquid ; methods ; Limit of Detection ; Reproducibility of Results ; Workplace

OBJECTIVETo explore the effects of low-dose chlorpyrifos (CPF) exposure on dopaminergic (DA) neurons in the midbrain substantia nigra and neural behavioral development in neonatal rats.

METHODSPostnatal 11 day old Sprague-Dawley rats were randomly assigned into CPF, menstruum dimethysulfoxide (DMSO) and normal saline (NS) groups. The rats in the CPF group were injected with low-dose CPF (5 mg/kg?d) on postnatal days 11-14. The two control groups were injected with DMSO or NS respectively. The rats were sacrificed on postnatal days 15, 20, 30, and 60. Body weight gain, outward appearance of brain tissue, the coefficient of brain and the water content of brain tissue were measured. Tyrosine hydroxylase (TH) expression in DA neurons in the midbrain substantial nigra was examined by immunohistochemical straining. Immune electron microscopy was used to examine the subcellular structure of DA neurons. Open field test, grip strength test, slope test and Morris water maze test were used to examine the neurobehavioral changes.

RESULTSThe outward appearance of brain tissue was normal in the three groups. There were no significant differences in the absolute value of body weight gain, the coefficient of brain and the water content of brain tissue among the three groups. CPF exposure decreased the level of TH immunoreactivity (P<0.05) in the substantia nigra of CPF group since postnatal day 30 compared with the DMSO and NS groups. The subcellular structures of some DA neurons in the CPF group were impaired. Decreased motor activity and learning and memory impairments were observed in the CPF group compared with those in the DMSO and NS groups (P<0.05) since postnatal day 30.

CONCLUSIONSCPF exposure during the neonatal period can cause long-term motor activity and learning and memory impairments in accompany with DA neurons damage in the midbrain substantia nigra.

Animals ; Animals, Newborn ; Behavior, Animal ; drug effects ; Chlorpyrifos ; toxicity ; Dopaminergic Neurons ; drug effects ; Female ; Insecticides ; toxicity ; Learning ; drug effects ; Male ; Motor Activity ; drug effects ; Rats ; Rats, Sprague-Dawley ; Substantia Nigra ; drug effects

OBJECTIVETo observe the effects of low concentration of organophosphate pesticide chlorpyrifos (CPF) prenatal exposure on generation mouse brain development.

METHODS5 mg/kg CPF was administered daily on gestation days (GD) 7.5 - 11.5. On postnatal day (PD) 35, quantitative morphologic examines were measured in CA1, CA3, dentate gyrus regions of the hippocampus and somatosensory cortex.

RESULTSAfter CPF prenatal exposure, selective morphology impairments were observed, showing 22.37%, 25.66% thinning of the CA1 and CA3 layers, 24.14% enlargement of the dentate guys and 81.77% to 74.61% decreasing of the ratio of neuron/glial of the somatosensory cortex.

CONCLUSIONThere maybe slight morphological changes after prenatal low concentration pesticide exposure even without obviously systemic toxicity.

Animals ; Chlorpyrifos ; toxicity ; Female ; Hippocampus ; drug effects ; pathology ; Insecticides ; toxicity ; Male ; Mice ; Mice, Inbred ICR ; Pregnancy ; Prenatal Exposure Delayed Effects ; Somatosensory Cortex ; drug effects ; pathology

OBJECTIVETo explore the effect of organophosphorus insecticides (OPs) on G protein-coupled receptor kinase 2 mediated phosphorylation of M2 muscarinic receptors in vitro and to understand an alternative target of the OPs for human and other animals.

METHODSThe acetylcholine M2 muscarinic receptors (mAChR2) were purified from rat brain by single step affinity chromatography. In vitro experiments, the purified mAChR2, G-protein coupled receptor kinase 2 (GRK2) and the (gamma-p32) labeled ATP were incubated with paraoxon (PO), chlorpyrifos oxon (CPO) or chlorpyrifos (CPF) of varying concentrations. The proteins were separated by the polyacrylamide gel electrophoresis. The gels were dried and the phosphorylation of mAChR2 was detected with autoradiograms. Bands containing M2 receptor were excised and counted by liquid scintillation.

RESULTSCPO inhibited phosphorylation of M2 muscarinic receptors by GRK2 with a median inhibition concentration (IC(50)) at 70 micromol/L. CPF also inhibited M2 receptors phosphorylation, but was less potent and less efficacious than that of CPO. PO and parathion (PT) had little effect on the receptor phosphorylation under the same conditions. CPO and CPF didn't inhibit the beta2 Adrenalin (beta2-AR) receptor phosphorylation also mediated by GRK2.

CONCLUSIONCPO and CPF can selectively inhibit the GRK2 mediated mAChR2 phosphorylation while PO and PT have no this effect.

Animals ; Chlorpyrifos ; analogs & derivatives ; toxicity ; Cholinesterase Inhibitors ; toxicity ; G-Protein-Coupled Receptor Kinase 2 ; Paraoxon ; toxicity ; Phosphorylation ; Rats ; Receptor, Muscarinic M2 ; metabolism ; beta-Adrenergic Receptor Kinases ; metabolism ; physiology

Animals ; Body Temperature ; drug effects ; Chlorpyrifos ; toxicity ; Environmental Exposure ; Female ; Rats ; Rats, Wistar ; Temperature

Animals ; Blood Pressure ; drug effects ; Chlorpyrifos ; toxicity ; Hypothermia ; chemically induced ; physiopathology ; Pesticides ; toxicity ; Rats ; Rats, Inbred LEC

OBJECTIVETo explore the effect of organophosphorus insecticides (OPs) on the nicotinic autoreceptor function (NAF) in rat cortical synaptosomes and to understand alternative target of the OPs for human and other animals.

METHODSIn vitro experiment, synaptosomes from the rats were incubated with [(3)H] choline and then superfused with physiological buffer. The [(3)H] acetylcholine release from the synaptosomes after the addition of paraoxon or chlorpyrifos to the superfusion system was recorded and the changes of NAF were calculated. In vivo experiment, NAF and acetylcholinesterase (AChE) activity in the cortical synaptosomes in the adult rats dosed with chlorpyrifos were also determined 96 h after OPs treatment.

RESULTSParaoxon caused slight effect on NAF (average inhibition rate: < 23%) while chlorpyrifos oxon caused > 100% of inhibition on NAF in vitro. Chlorpyrifos markedly reduced NAF by 66% 96 h after treatment and inhibited the AChE activity by 91% in vivo.

CONCLUSIONThe OPs may have different effects on the NAF of rat cortical synaptosomes while chlorpyrifos may certainly inhibit the NAF in cortical synaptosomes of adult rats.

Acetylcholine ; secretion ; Animals ; Brain ; drug effects ; metabolism ; Chlorpyrifos ; toxicity ; In Vitro Techniques ; Insecticides ; toxicity ; Paraoxon ; toxicity ; Rats ; Receptors, Nicotinic ; physiology ; Synaptosomes ; drug effects ; metabolism