Analysis of endosulfan and its metabolites in rat plasma and selected tissue samples by gas chromatography-mass spectrometry

Endosulfan induced cell death in Sertoli-germ cells of male Wistar rat follows intrinsic mode of cell death

Health of germ cells may affect production of quality gametes either due to endogenous or exogenous factors. Pesticides are among the exogenous factors that can enter the organisms through various routes of exposure and also can affect the reproductive system of an organism. Endosulfan is an organochlorine cyclodiene pesticide used widely for controlling agricultural pests. It has been shown to induce reproductive dysfunctions such as sperm abnormalities, reduced intracellular spermatid count in exposed organisms. Germ cells being the progenitor cells for male gametes and Sertoli cells as their nourishing cells, we examined whether endosulfan induces cell death in Sertoli-germ cells of male rats. Sertoli-germ cells, isolated from 28 d old male Wistar rats, were exposed to endosulfan (2.0, 20.0 and 40.0 μg mL(-1)) for 24-72 h. Cytotoxicity, endosulfan concentration, reactive oxygen species (ROS) generation, oxidative stress parameters were measured in these cells in the absence or presence of endosulfan for the above mentioned exposure periods and subsequently, cell death endpoints were measured. We detected endosulfan in the exposed cells and demonstrated increased cell death in exposed Sertoli-germ cells as evidenced by a significant increase in annexin-V staining, depolarization of mitochondrial membrane, caspase-9 and -3 activities and BAD and PARP cleavage activities and DNA ladder formation along with non-significant increase in autophagic cell death. The study suggests that endosulfan can cause cell death in exposed Sertoli-germ cells due to higher oxidative damage with the activation of intrinsic cell death pathway which may eventually affect the production of quality gametes.

Determination of pesticides in postmortem blood and bone marrow of pesticide treated rabbits

Forensic toxicological analyses have traditionally focused on the use of blood, body fluids, and certain organs in examinations of deaths due to intoxication. However, in some situations, putrefaction and contamination make proper sampling from tissues impossible, such as in exhumation cases. In these cases, bone marrow might be useful as an alternative specimen since it is a potential depot for drugs. This study aims to determine pesticides in postmortem and putrefied bone marrow of pesticide treated rabbits, so as to reveal the diagnostic value of toxicological analysis of bone marrow in exhumation cases. Out of thirteen rabbits, a 110 mg/kg dose of endosulfan was orally given to six through a gavage tool, and a 2500 mg/kg dose of diazinon was given to six using the same method. One rabbit was not treated with anything and served as a control sample. Venous blood, liver, lung, kidney, brain, and bone marrow samples were collected just after spontaneous death or cervical dislocation. After this, the rabbits were buried in soil. All of them were exhumed 1 month later, and putrefied viscera and bone marrow were sampled. Blood and tissue samples underwent solvent extraction and solid phase extraction, and then the samples were analyzed by GC-MS. Mean residue levels of diazinon in early postmortem samples were 85 mg/kg, 71 mg/kg, 23 mg/kg, 21 mg/kg, 19 mg/kg, and 0.4 mg/l in the liver, bone marrow, kidney, lung, brain, and blood, respectively. Mean residue levels of diazinon in the putrefied body were 3327 mg/kg in putrefied viscera and 1783 mg/kg in the bone marrow. Mean residue levels of endosulfan isomers and metabolites in early postmortem samples (blood, liver, lung, kidney, brain, and bone marrow) were 0.46 mg/kg (endosulfan sulfate), 0.32 mg/kg (alpha and beta isomers of endosulfan), and 0.14 mg/kg (endosulfan ether) while the same levels were 0.26 mg/kg (endosulfan sulfate), 0.24 mg/kg (alpha and beta isomers of endosulfan), and 0.1 mg/kg (endosulfan ether) in putrefied samples (putrefied bone marrow and putrefied viscera). Based on these experimental results, it can be concluded that cause of death can be determined as acute pesticide poisoning by toxicological analysis of samples from bone marrow and putrefied viscera in exhumation cases.

Maternal residence near agricultural pesticide applications and autism spectrum disorders among children in the California Central Valley

BACKGROUND

Ambient levels of pesticides ("pesticide drift") are detectable at residences near agricultural field sites.

OBJECTIVE

Our goal was to evaluate the hypothesis that maternal residence near agricultural pesticide applications during key periods of gestation could be associated with the development of autism spectrum disorders (ASD) in children.

METHODS

We identified 465 children with ASD born during 1996-1998 using the California Department of Developmental Services electronic files, and matched them by maternal date of last menstrual period to 6,975 live-born, normal-birth-weight, term infants as controls. We determined proximity to pesticide applications using California Department of Pesticide Regulation records refined using Department of Water Resources land use polygons. A staged analytic design applying a priori criteria to the results of conditional logistic regressions was employed to exclude associations likely due to multiple testing error.

RESULTS

Of 249 unique hypotheses, four that described organochlorine pesticide applications--specifically those of dicofol and endosulfan--occurring during the period immediately before and concurrent with central nervous system embryogenesis (clinical weeks 1 through 8) met a priori criteria and were unlikely to be a result of multiple testing. Multivariate a posteriori models comparing children of mothers living within 500 m of field sites with the highest nonzero quartile of organochlorine poundage to those with mothers not living near field sites suggested an odds ratio for ASD of 6.1 (95% confidence interval, 2.4-15.3). ASD risk increased with the poundage of organochlorine applied and decreased with distance from field sites.

CONCLUSIONS

The association between residential proximity to organochlorine pesticide applications during gestation and ASD among children should be further studied.

A physiologically based pharmacokinetic model for endosulfan in the male Sprague-Dawley rats

Endosulfan, an organochlorine (OC) insecticide belonging to the cyclodiene group, is one of the most commonly used pesticides to control pests in vegetables, cotton, and fruits. To date, no physiologically based pharmacokinetic (PBPK) model has been located for endosulfan in animal species and humans. The estimation by a mathematical model is essential since information on humans can scarcely be obtained experimentally. The PBPK model was constructed based on the pharmacokinetic data of our experiment following single oral administration of (14)C-Endosulfan to male Sprague-Dawley rats. The model was parameterized by using reference physiological parameter values and partition coefficients that were determined in the experiment and optimized by manual adjustment until the best visual fit of the simulations with the experimental data were observed. The model was verified by simulating the disposition of (14)C-Endosulfan in vivo after single and multiple oral dosages and comparing simulated results with experimental results. The model was further verified by using experimental data retrieved from the literature. The present model could reasonably predict target tissue dosimetries in rats. Simulation with three-time repeated administration of (14)C-Endosulfan and experimental data retrieved from the literature by the constructed model fitted fairly well with the experimental results; thus suggesting that the newly developed PBPK model was developed. Sensitivity analyses were used to determine those input parameters with the greatest influence on endosulfan tissue concentrations.

Toxicokinetics of 14C-endosulfan in male Sprague-Dawley rats following oral administration of single or repeated doses

Endosulfan (ES), an organochlorine (OC) insecticide that belongs to the cyclodiene group, is one of the most commonly used pesticides to control pests in vegetables, cotton, and fruits. The toxicokinetics of 14C-endosulfan following oral administration of a single dose of 5 mg/kg body weight was investigated in male Sprague-Dawley rats. Three rats were sacrificed 30 min, 1 h, 2 h, 4 h, and 8 h after dosing. 14C-endosulfan radioactivity was detected in all tissues at each time point. In a separate experiment urine and feces were collected for 96 h. The total radioactivity recovered in the excreta for 4 days was 106.8% +/- 26.2%, with fecal elimination the major route of elimination route (94.4% +/- 21.4%). The cumulative excretion in the urine for 4 days was 12.4% +/- 4.8%. Radioactivity 8 h after administration was highest in gastrointestinal (GI) tract tissue (20.28 +/- 16.35 mg ES eq./L) and lowest in muscle (0.18 +/- 0.06 mg ES eq./L). The toxicokinetic parameters obtained from 14C-endosulfan-derived radioactivity in blood were distribution half-life (T1/2 x) = 31 min and terminal elimination half-life (T1/2 y) = 193 h. Blood concentration reached its maximum (Cmax) of 0.36 +/- 0.08 mg ES eq./L 2 h after the oral dose. Endosulfan was rapidly absorbed into the GI tract in rats, with an absorption rate constant (ka) of 3.07 h(-1).