Chlordane Exposure Research Articles

Chlordane exposure impairs the growth and behavior of Drosophila

Chlordane, a previously extensively utilized insecticidal pesticide, has since been prohibited, however, owing to its limited degradability, it continues to persist significantly in soil and water reservoirs, subsequently accumulating within plant and animal organisms, representing a substantial threat to human health. Despite extensive research conducted over the past few decades to investigate the toxic effects of chlordane, there remains a notable dearth of studies focusing on its impact on sleep activity. Therefore, in this study, the effects of short-term and long-term exposure to chlordane on the activity and sleep of Drosophila were investigated. When exposed to chlordane at a concentration of 1 μM, Drosophila lost body weight, decreased body size and resulted in lipid metabolism disorders. In addition, chlordane exposure altered the arousal and sleep behaviors of Drosophila. Short-term exposure to chlordane resulted in an increase in night-time sleep duration, while long-term exposure to chlordane resulted in an increase in activity and a decrease in sleep, as evidenced by a decrease in the duration of each sleep session and the appearance of sleep fragmentation. Under conditions of long-term chlordane exposure, reactive oxygen species levels were significantly up-regulated in Drosophila. Our results suggest that long-term chlordane exposure triggers oxidative stress damage in Drosophila, leading to sleep disruption. This study offers novel insights into the harmful impacts of environmental pollutants on human sleep patterns and proposes that mitigating the presence of chlordane in the environment could potentially contribute to the reduction of global sleep disorder prevalence.

Sex-specific effects of acute chlordane exposure in the context of steatotic liver disease, energy metabolism and endocrine disruption.

Chlordane is an organochlorine pesticide (OCP) that is environmentally persistent. Although exposures to OCPs including chlordane have been associated with elevated liver enzymes, current knowledge on OCPs' contribution to toxicant-associated steatotic liver disease (TASLD) and underlying sex-specific metabolic/endocrine disruption are still widely limited. Therefore, the objective of this study was to investigate the sex-dependent effects of chlordane in the context of TASLD. Age-matched male and female C57BL/6 mice were exposed to chlordane (20mg/kg, one-time oral gavage) for two weeks. Female mice generally exhibited lower bodyfat content but more steatosis and hepatic lipid levels, consistent with increased hepatic mRNA levels of genes involved in lipid synthesis and uptake. Surprisingly, chlordane-exposed females demonstrated lower hepatic cholesterol levels. With regards to metabolic disruption, chlordane exposure decreased expression of genes involved in glycogen and glucose metabolism (Pklr, Gck), while chlordane-exposed females also exhibited decreased gene expression of HNF4A, an important regulator of liver identity and function. In terms of endocrine endpoints, chlordane augmented plasma testosterone levels in males. Furthermore, chlordane activated hepatic xenobiotic receptors, including the constitutive androstane receptor, in a sex-dependent manner. Overall, chlordane exposure led to altered hepatic energy metabolism, and potential chlordane-sex interactions regulated metabolic/endocrine disruption and receptor activation outcomes.

Chlordane exposure causes developmental delay and metabolic disorders in Drosophila melanogaster

The incidence of metabolic diseases is increasing every year, and several studies have highlighted the activity of persistent organic pollutants (POPs) in causing hyperlipidemia and diabetes, and these compounds are considered to be endocrine disrupting chemicals (EDCs). Chlordane is classified as an endocrine disruptor, but the mechanism of how it functions is still unclear. This study investigates the effects of chlordane exposure on Drosophila larvae. Drosophila was cultured in diet containing 0.01 μM, 0.1 μM, 1 μM, 5 μM, and 10 μM chlordane, and the toxicity of chlordane, the growth and development of Drosophila, the homeostasis of glucose and lipid metabolism and insulin signaling pathway, lipid peroxidation-related indicators and Nrf2 signaling pathway were evaluated. We here found that exposure to high concentrations of chlordane decreased the survival rate of Drosophila and that exposure to low concentrations of chlordane caused disruption of glucose and lipid metabolism, increased insulin secretion and impairment of insulin signaling. Notably, it also led to massive ROS production and lipid peroxidation despite of the activation of Nrf2 signaling pathway, an important pathway for maintaining redox homeostasis. Collectively, chlordane causes lipid peroxidation and disrupts redox homeostasis, which may be a potential mechanism leading to impaired insulin signaling and the metabolism of glucose and lipid, ultimately affects Drosophila development.

Keystone taxa shared between earthworm gut and soil indigenous microbial communities collaboratively resist chlordane stress

Chlordane is an organochlorine pesticide that is applied extensively. Residual concentrations that remain in soils after application are highly toxic to soil organisms, particularly affecting the earthworm gut and indigenous soil microorganisms. However, response mechanisms of the earthworm gut and indigenous soil microorganism communities to chlordane exposure are not well known. In this study, earthworms (Metaphire guillelmi) were exposed to chlordane-contaminated soils to investigate their response mechanisms over a gradient of chlordane toxicity. Results from high-throughput sequencing and network analysis showed that the bacterial composition in the earthworm gut varied more significantly than that in indigenous soil microbial communities under different concentrations of chlordane stress (2.3–60.8 mg kg−1; p < 0.05). However, keystone species of Flavobacterium, Candidatus Nitrososphaera, and Acinetobacter remained stable in both the earthworm gut and bacterial communities despite varying degrees of chlordane exposure, and their relative abundance was slightly higher in the low-concentration treatment group (T1, T2) than in the high-concentration treatment group (T3, T4). Additionally, network analysis demonstrated that the average value of the mean degree of centrality, closeness centrality, and eigenvector centrality of all keystone species screened by four methods (MetagenomeSeq, LEfSe, OPLS-DA, Random Forest) were 161.3, 0.5, and 0.63, respectively, and that these were significantly higher (p < 0.05) than values for non-keystone species (84.9, 0.4, and 0.2, respectively). Keystone species had greater network connectivity and a stronger capacity to degrade pesticides and transform carbon and nitrogen than non-keystone species. The keystone species, which were closely related to the microbial community in soil indigenous flora and earthworm intestinal flora, could resist chlordane stress and undertake pesticide degradation. These results have increased understanding of the role of the earthworm gut and indigenous soil bacteria in resisting chlordane stress and sustaining microbial equilibrium in soil.

Elevated Serum Oxychlordane is Associated with Increased Risk of Metabolic Syndrome: Results from the National Health and Nutrition Examination Survey 1999‐2004

Obesity, diet, and physical inactivity are risk factors commonly associated with metabolic syndrome (MetS). However, exposure to chlordane, a persistent organic pesticide that has been banned in the US since 1983, has been associated with metabolic risk. Chlordane continues to be found in indoor air of homes treated for termites as well as in foods. The objective of this research was to use the most recent non‐pooled NHANES data on chlordane exposure (1999‐2004) and its effect on metabolic syndrome risk. Data from NHANES were used to calculate odds ratios for metabolic syndrome, each of its five risk component measures, and related health markers in relationship with subjects' plasma oxychlordane concentrations. The logistic regression model used was adjusted for the influence of age, gender, ethnicity, BMI, and poverty income ratio. A total of 3465 adult subjects were used in this study. A significant relationship was found between plasma oxychlordane concentration (OR of highest quartile compared to the lowest quartile, 95% CI) and the prevalence of MetS (2.58, 1.80‐3.71), hypertriglyceridemia (3.26, 1.92‐5.46), elevated waist circumference (2.24, 1.34‐3.76), elevated blood pressure (2.58, 1.96‐3.38), and hyperglycemia (2.05, 1.23‐3.42). Additional post hoc analyses showed that high oxychlordane concentrations were also significantly related to elevated glycosylated hemoglobin, C‐reactive protein, and the homeostatic assessment of insulin resistance (HOMA‐IR). In conclusion, despite a nearly 20 year ban on its use, a significant association between plasma oxychlordane concentration and risk for metabolic syndrome exists.

Maternal Pregnancy Levels of trans -Nonachlor and Oxychlordane and Prevalence of Cryptorchidism and Hypospadias in Boys

Background: The etiologies of the male urogenital anomalies—cryptorchidism and hypospadias—are poorly understood. Given positive associations between chlordane isomers and testicular germ cell tumors, it is reasonable to assume that chlordanes might also be associated with other testicular dysgenesis syndrome disorders, namely cryptorchidism and hypospadias.Objective: To examine whether exposure to in utero chlordane is related to cryptorchidism and hypospadias, we evaluated levels of chlordane derivatives, trans-nonachlor and oxychlordane, among pregnant women enrolled in the Collaborative Perinatal Project (CPP).Methods: From 1959 to 1965, the CPP enrolled pregnant women at 12 U.S. medical centers. We analyzed serum trans-nonachlor and oxychlordane levels measured in third-trimester serum from the mothers of 217 sons with cryptorchidism, 197 sons with hypospadias, and 557 sons with neither condition. Adjusted odds ratios (ORs) and 95% confidence intervals were calculated using conditional logistic regression.Results: The quartile-specific ORs for cryptorchidism or hypospadias show no notable associations with trans-nonachlor or oxychlordane. Further, there were no significant trends with increasing quartile of maternal trans-nonachlor or oxychlordane level in either cryptorchidism or hypospadias (p-trend all > 0.45).Conclusions: The results do not support an association between chlordane levels and cryptorchidism or hypospadias. It is unlikely that current chlordane exposure is related to the development of either anomaly, given that serum chlordane levels at the time of sample collection, the early 1960s, were considerably higher than levels at present.

Tissue concentrations of chlordanes in mice after long-term exposures to technical grade chlordane at indoor air levels

We determined concentrations of chlordanes (5 chlordane compounds and 2 metabolites) in tissues and organs of mice following a prolonged exposure to Chlordane (technical grade chlordane) at levels as low as those in indoor air.After exposure to 4.22-11.36 μ g/m(3) Chlordane (total of 5 compounds) in the air for 1-6 months, 6.44-13.00 ppm chlordanes (total of 7 compounds) were detected in mice (2 tissues and 6 organs). The adipose tissue among the 2 tissues / 6 organs examined contained the highest chlordanes. The ratio of the adipose tissue chlordanes to the liver chlordanes was approximately 5.6 times, followed by the muscle (0.9), lungs (0.4), kidneys (0.4), heart (0.3), spleen (0.2) and brain (0.1). In addition, trans-nonachlor, oxychlordane and heptachlorepoxide in chlordanes were at a high level.The level of Chlordane exposure (dose) and the level of chlordanes accumulation in each tissue or organ of the mice except for the heart were closely correlated (r=0.9388-0.7130), and showed a linear relationship. The tendency of chlordanes accumulation in light of the linear relationship was adipose ≫ liver ≥ muscle.Thus, even with a low level of Chlordane in indoor air, chlordanes may be steadily accumulated in the bodies of human residents with prolonged exposure similarly. The present findings suggest that it is necessary to investigate die risk of organochlorine chemicals contamination in indoor air at prolonged exposure.

Topical exposure to chlordane reduces the contact hypersensitivity response to oxazolone in BALB/c mice

Previous studies have shown that prenatal exposure to the organochlorine pesticide chlordane significantly decreases the ear swelling response to the contact allergen oxazolone in BALB/c mice. Alterations of macrophage function in the efferent arm of the contact hypersensitivity response have also been reported. In the current study, chlordane was applied topically and the effects of oxazolone-induced contact hypersensitivity were determined. Initially, the reduction in oxazolone-induced ear swelling in topically-exposed female BALB/c mice was compared to 30-day-old BALB/c female mice exposed prenatally to chlordane. Prenatal chlordane exposure induced a 36% reduction in ear swelling compared to a 60% reduction following topical treatment at the challenge phase. Topically-applied chlordane also reduced the oxazolone-induced ear swelling by 40% when applied at sensitization. When applied at both sensitization and challenge, ear swelling was reduced by 71%. In a time-course study, it was determined that chlordane must be applied at the time of sensitization, challenge or both or within 1 h post-challenge to significantly reduce ear swelling. A dose-response study showed that the lowest concentration of chlordane resulting in a significantly reduced ear swelling response was 20 μg per ear.

Hepatocarcinogenicity of chlordane in B6C3F1 and B6D2F1 male mice: evidence for regression in B6C3F1 mice and carcinogenesis independent of ras proto-oncogene activation.

Logistic regression analysis of age-specific prevalences for neoplastic and non-neoplastic liver lesions was used to examine treatment responses for B6C3F1 and B6D2F1 male mice continuously exposed to chlordane (55 p.p.m.) and to determine whether neoplasms were dependent on continuous exposure in the B6C3F1 mice. In order to determine if ras oncogene activation plays a role in the carcinogenicity of chlordane and whether the activation is dependent on genetic background, liver tumors from chlordane-treated B6C3F1 and B6D2F1 mice were analyzed for the presence of activating mutations in the ras oncogene. The overall liver tumor prevalence at terminal killing was nearly 100% for both strains; however, the age-specific prevalence increased more rapidly in B6C3F1 mice than in B6D2F1 mice. Tumor-bearing B6C3F1 mice had an average of two or more tumors per liver than B6D2F1 mice at their respective terminal killings (5.4 versus 3.3). When chlordane exposure was discontinued for a group of B6C3F1 mice ('stop' group) at 491 days of age, overall tumor multiplicity significantly decreased by 30% from an average of 4.4 per tumor-bearing-animal at 525 days to 3.1 at terminal killing (568 days). Over the same time period the prevalence of hepatocellular carcinomas significantly decreased from 80 to 54% and adenomas from 100 to 93% by terminal killing in B6C3F1 'stop-group' mice. Chlordane induced diffuse hepatocellular centrilobular hypertrophy, frequent multinucleate hepatocytes, toxic change and hepatoproliferative lesions composed predominantly of acidophilic hepatocytes in nearly 100% of both the B6C3F1 and B6D2F1 mice. The development of histological evidence of toxicity closely paralleled the temporal development of hepatocellular neoplasia and decreased in severity when the tumor burden was maximal. No H- or K-ras mutations were detected in the chlordane-induced hepatocellular tumors in B6C3F1 mice (15 adenomas and 15 carcinomas) or B6D2F1 mice (10 adenomas and 10 carcinomas). In conclusion, chlordane induced liver tumors in both B6C3F1 and B6D2F1 male mice by mechanisms independent of ras oncogene activation and 30% of both benign and malignant liver tumors in the B6C3F1 mice regressed after exposure was discontinued.

Protracted neurotoxicity from chlordane sprayed to kill termites.

Over 250 adults and children were exposed to chlordane when the wooden building surfaces and soil around an apartment complex were sprayed in 1987. Two hundred-sixteen adults had neurobehavioral functions measured and completed questionnaires for symptom frequency, mood status, confounding factors, and medical, rheumatic, and respiratory disorders in 1994. Measurements included simple and choice reaction time, balance, blink reflex latency, color vision, cognitive, perceptual motor, memory, and recall functions. We analyzed 216 exposed and 174 referent adults. Age, educational level, weight, height, and gender ratio were similar for the exposed and referent groups. Performance of balance, reaction times, Culture Fair, digit symbol, verbal recall, and trail-making were significantly impaired in exposed persons compared to referents. Mood-state scores were elevated, as were the frequencies of respiratory, neurobehavioral, and rheumatic symptoms. In contrast, long-term memory function was similar in both groups, consistent with its status before exposure. There was no identified bias or confounding factors. Chlordane exposure was associated with protracted impairment of neurophysiological and psychological functions. The central nervous system is the most important target of chlorinated cyclodiene insecticides. Human exposure should be prohibited.

Gender-Specific Effects of Prenatal Chlordane Exposure on Myeloid Cell Development

Gender-Specific Effects of Prenatal Chlordane Exposure on Myeloid Cell Development. Blyler, G., Landreth, K. S., and Barnett, J. B. (1994). Fundam. Appl. Toxicol. 23, 188-193 Work previously reported by this laboratory indicated that prenatal chlordane exposure affected macrophage function in young adult mice. Because these macrophage effects were due to exposure during the development of the immune system, the possibility of a persistent effect on the development of myeloid stem and progenitor cells was considered. Female mice were treated with either 0 or 8 mg of chlordane per kilogram body weight daily for 18 days during pregnancy. Myeloid hemopoietic activity of bone marrow cells from 6-week-old offspring was evaluated for in vitro colony-forming units-in-culture in response to exogeneously added recombinant forms of the cytokines granulocyte/macrophage-colony stimulating factor, macrophage-CSF, and interleukin 3 (IL-3). There was a significant depression of the numbers of bone marrow colony forming units-granulocyte/macrophage (CFU-GM). CFU-IL-3, and CFU-macrophage (CFU-M) in only the female offspring. Male offspring consistently demonstrated no difference in the CFU-GM, CFU-IL-3, or CFU-M. Prenatal treatment with chlordane did not significantly affect the number of recoverable viable bone marrow cells in either male or female mice.

The Effects of Chlordane Exposure during Pre- and Postnatal Periods at Environmentally Relevant Levels on Sex Steroid-Mediated Behaviors and Functions in the Rat

Technical chlordane is a mixture of four main isomers (i.e., heptachlor, cis-chlordane, trans-chlordane, and trans-nonachlor) found in meat and dairy products as well as in indoor air of houses treated for termites. These isomers are metabolized to more potent epoxides (heptachlor epoxide and oxychlordane) which accumulate in lipid compartments of tissues and have been shown to reduce chloride influx through GABA A receptor complex channels and to alter steroid levels. However, considering the almost universal human exposure and the potential for accumulation of these agents, very little is known about how chronic, low-level exposures during development affect adult behavior and steroid-mediated processes. Time-pregnant Sprague-Dawley dams (Day 4 of gestation through Day 21 of lactation) and offspring (Day 22 of age through Day 80) were exposed to three levels of technical chlordane (100, 500, or 5000 ng/g) on a daily schedule. The low-exposure level generated heptachlor epoxide and oxychlordane plasma levels in the dam (Day 20) and in the offspring (Day 80) representative of those found in the U.S. populace. Chlordane-dosed offspring exhibited sex- and dose-dependent effects on testosterone levels, behavioral tests, and body weight conducted between postnatal Days 77 and 85. Chlordane-dosed females, but not males, had significant decreases in testosterone levels, significant improvements in spatial abilities (i.e., decreases in Cincinnati maze errors, navigation times, and failures to escape), and significant increases in body weight and in auditory startle-evoked responses. In two other tests, only males were used. These chlordane-dosed males showed significant increases in male-typical mating behaviors and decreases in 36Cl − uptake into brain microsacs. For all behavioral and body weight measurements, dose-response effects were observed for the 100 and 500 ng/g dosed groups. However, the 5000 ng/g dose group responses were closer to those of control values. These results suggest that these cyclodienes masculinize sexually dimorphic functions and behaviors by mimicking sex steroids and/or changing their levels.

Gender-Specific Effects of Prenatal Chlordane Exposure on Myeloid Cell Development

Gender-Specific Effects of Prenatal Chlordane Exposure on Myeloid Cell Development

Macrophage tumoricidal mechanisms are selectively altered by prenatal chlordane exposure.

Macrophages (m phi) derived from mice treated in utero with chlordane show a significant delay of tumoricidal induction activity. In this study, m phi from chlordane-treated animals required a 48 h in vitro period of induction with interferon-gamma and lipopolysaccharide (IFN/LPS) before they could kill P815 targets. Similarly, m phi from chlordane-treated animals also failed to produce an immediate H2O2 burst upon perturbation. Conversely, their stimulated control m phi counterparts were tumoricidal by 2 h and exhibited a respiratory burst without any delay. Moreover, levels of the second messenger, inositol triphosphate (IP3), were significantly delayed in chlordane-treated animals following interaction with IFN/LPS. When nitrate/nitrite production was analyzed as an alternate mechanism for killing tumors, stimulated m phi from both normal and chlordane-treated animals responded equally. The data show that chlordane differentially introduces defects in m phi biochemical mechanisms associated with tumor killing.

Alteration of fetal liver colony formation by prenatal chlordane exposure

Female mice were treated with 0 or 8 mg/kg chlordane daily for 18 days during pregnancy. The fetuses of these mice were assayed for fetal liver hematopoietic activity at 18 days gestational age. Hematopoietic activity was evaluated for in vitro granulocyte-macrophage colony-forming units (GM-CFU) and in vivo spleen CFU (CFU-S). The consistent finding was a significant depression of the numbers of both fetal liver GM-CFU and CFU-S without a change in liver cellularity in fetuses exposed to 8 mg/kg chlordane. These data show that the damage to stem cells that persists into adult life as a result of chlordane exposure, as reported earlier by Barnett et al. (1990) Fundam. Appl. Toxicol. 14, 688–695, occurred during the fetal period.

Interruption of chronic chlordane exposure and plasma residue levels in occupational workers

Chlordane, which had been exclusively used for termite control, was completely prohibited in September 1986 in Japan, not only with respect to use but also with respect to import and manufacture. Some findings were reported previously regarding the accumulative characteristics of transnonachlor and oxychlordane in the plasma of spraymen following chlordane exposure. However, there has been no report on the residual disposition of these chlordane-related compounds in humans. Therefore, the levels of these residual compounds in the plasma of occupational workers were monitored after they ceased use of the insecticide. The present paper describes the time course of the changes in the levels of these lipophilic organochloride compounds after termination of the use of chlordane.

Long-term alteration of adult bone marrow colony formation by prenatal chlordane exposure

Female mice were treated with either 0, 4, or 8 mg of chlordane per kilogram body weight daily for 18 days during pregnancy. The offspring of these mice were assayed for bone marrow hematopoietic activity at 100 and 200 days of age. Hematopoietic activity was evaluated for in vitro granulocyte-macrophage colony-forming units (GM-CFU) and in vivo spleen CFU (CFU-S). The consistent finding was a significant depression both of the numbers of bone marrow GM-CFU and of the CFU-S in offspring exposed to either 4 or 8 mg/kg chlordane even at 100 and 200 days after cessation of treatment. Prenatal treatment with chlordane did not affect the number of recoverable viable bone marrow cells at either of these time points. Ontological development was selectively affected by chlordane exposure, since subchronic (18 day) treatment of adult mice did not significantly alter bone marrow GM-CFU or CFU-S levels. These data suggest that the decreased delayed-type hypersensitivity reactions noted previously in mice exposed to chlordane prenatally may be due to a change in the functional capacity of myeloid lineage cells rather than altered T cell function.

Long-Term Alteration of Adult Bone Marrow Colony Formation by Prenatal Chlordane Exposure

Long-Term Alteration of Adult Bone Marrow Colony Formation by Prenatal Chlordane Exposure. BARNETT, J. B., BLAYLOCK, B. L., GANDY, J., MENNA, J. H., DENTON, R., AND SODERBERG, L. S. F. (1990). Fundam. Appl. Toxicol. 14, 688–695. Female mice were treated with either 0, 4, or 8 mg of chlordane per kilogram body weight daily for 18 days during pregnancy. The offspring of these mice were assayed for bone marrow hematopoietic activity at 100 and 200 days of age. Hematopoietic activity was evaluated for in vitro granulocyte-macrophage colony-forming units (GM-CFU) and m vivo spleen CFU (CFU-S). The consistent finding was a significant depression both of the numbers of bone marrow GM-CFU and of the CFU-S in offspring exposed to either 4 or 8 mg/kg chlordane even at 100 and 200 days after cessation of treatment. Prenatal treatment with chlordane did not affect the number of recoverable viable bone marrow cells at either of these time points. Ontological development was selectively affected by chlordane exposure, since subchronic (18 day) treatment of adult mice did not significantly alter bone marrow GM-CFU or CFU-S levels. These data suggest that the decreased delayed-type hypersensitivity reactions noted previously in mice exposed to chlordane prenatally may be due to a change in the functional capacity of myeloid lineage cells rather than altered T cell function.

Neurobehavioral sequelae of chlordane exposure : Zillmer, E.A., Barth, J.T., Golden, C.J., & Rubin, S. Neuropsychology Program, Department of Psychology, Sociology, & Anthropology Drexel University Department of Behavioral Medicine & Psychiatry, University of Virginia Medical School

Neurobehavioral sequelae of chlordane exposure : Zillmer, E.A., Barth, J.T., Golden, C.J., & Rubin, S. Neuropsychology Program, Department of Psychology, Sociology, & Anthropology Drexel University Department of Behavioral Medicine & Psychiatry, University of Virginia Medical School

Alteration of Fetal Liver Colony Formation by Prenatal Chlordane Exposure

Alteration of Fetal Liver Colony Formation by Prenatal Chlordane Exposure