RESUMEN
The Juarez Valley is an important agricultural region in northern Mexico, conveniently organized into three modules (I to III). For decades, their soils have been exposed to organochlorine pesticides (OCPs) and also have been irrigated with wastewaters, which may contain heavy metals. Nowadays, there is very limited information regarding the presence of OCPs and heavy metals in these soils. Thus, the aim of this study was to diagnose these soils for OCPs and heavy metal content by using gas chromatography coupled with electron micro-capture detector and atomic absorption spectrometry, respectively. The results indicated that 4,4'-dichlorodiphenyldichloroethylene and 4,4'-dichlorodiphenyltrichloroethane were primarily disseminated across the three modules since they were found in 100% and 97% of the analyzed soils, respectively. According to international regulations, none of the determined OCP concentrations are out of the limits. Additionally, the Cu, Zn, Fe, Pb, and Mn were found in all sampled soils from the three modules. The highest concentration of Fe was found in module II (1902.7 ± 332.2 mg kg-1), followed by Mn in module III (392.43 ± 74.43 mg kg-1), Zn in module I (38.36 ± 26.57 mg kg-1), Pb in module II (23.48 ± 6.48 mg kg-1), and Cu in module I (11.04 ± 3.83 mg kg-1) (p ≤ 0.05). These values did not exceed the limits proposed by international standards. The Cd was detected in most of the analyzed soils and all their values, with an average of 2 mg kg-1, surpassed the Mexican standards (0.35 mg kg-1). This study has mapped the main OCPs and heavy metals in the Juarez Valley and can serve as a starting point to further monitor the behave of xenobiotics. Since these recalcitrant compounds might be bio-accumulated in biological systems, further analytical methods, as well as remediation techniques, should be developed.
Asunto(s)
Monitoreo del Ambiente/métodos , Hidrocarburos Clorados/análisis , Metales Pesados/análisis , Plaguicidas/análisis , Contaminantes del Suelo/análisis , Suelo/química , Riego Agrícola , Agricultura , Cromatografía de Gases y Espectrometría de Masas , México , Espectrofotometría Atómica , Aguas Residuales/químicaRESUMEN
BACKGROUND: Repeated alcohol exposure is known to increase subsequent ethanol consumption in mice. However, the underlying mechanisms have not been fully elucidated. One postulated mechanism involves epigenetic modifications, including histone modifications and DNA methylation of relevant genes such as NR2B or BDNF. METHODS: To investigate the role of epigenetic mechanisms in the development of alcohol drinking behavior, an established chronic intermittent ethanol exposure reinforced ethanol drinking mouse model with vapor inhalation over two 9-day treatment regimens was used. The DNA methyltransferase inhibitor, 5-azacytidine or the histone deacetylase inhibitor, Trichostatin A was administered (intraperitoneally) to C57BL/6 mice 30 min before daily exposure to chronic intermittent ethanol. Changes in ethanol consumption were measured using the 2-bottle choice test. RESULTS: The results indicated that systemic administration of Trichostatin A (2.5 µg/g) facilitated chronic intermittent ethanol-induced ethanol drinking, but systemic administration of 5-azacytidine (2 µg/g) did not cause the same effect. However, when 5-azacytidine was administered by intracerebroventricular injection, it facilitated chronic intermittent ethanol-induced ethanol drinking. Furthermore, the increased drinking caused by chronic intermittent ethanol was prevented by injection of a methyl donor, S-adenosyl-L-methionine. To provide evidence that chronic intermittent ethanol- or Trichostatin A-induced DNA demethylation and histone modifications of the NR2B promoter may underlie the altered ethanol consumption, we examined epigenetic modifications and NR2B expression in the prefrontal cortex of these mice. Chronic intermittent ethanol or Trichostatin A decreased DNA methylation and increased histone acetylation in the NR2B gene promoter, as well as mRNA levels of NR2B in these mice. CONCLUSIONS: Taken together, these results indicate that epigenetic modifications are involved in regulating ethanol drinking behavior, partially through altering NR2B expression.
Asunto(s)
Consumo de Bebidas Alcohólicas/genética , Epigénesis Genética , Acetilación/efectos de los fármacos , Consumo de Bebidas Alcohólicas/fisiopatología , Animales , Azacitidina/farmacología , Depresores del Sistema Nervioso Central/administración & dosificación , Metilación de ADN/efectos de los fármacos , Metilasas de Modificación del ADN/antagonistas & inhibidores , Metilasas de Modificación del ADN/metabolismo , Etanol/administración & dosificación , Inhibidores de Histona Desacetilasas/farmacología , Histonas/efectos de los fármacos , Histonas/metabolismo , Ácidos Hidroxámicos/farmacología , Masculino , Ratones Endogámicos C57BL , Corteza Prefrontal/fisiopatología , Regiones Promotoras Genéticas/efectos de los fármacos , ARN Mensajero , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismoRESUMEN
BACKGROUND: Increasing evidence indicates that repeated exposure to and withdrawal from alcohol can result in persistent molecular and cellular adaptations. One molecular adaptation that occurs is the regulation of gene expression, which is thought to lead to the functional alterations that characterize addiction: tolerance, dependence, withdrawal, craving, and relapse. MicroRNAs (miRNAs) have been recently identified as master regulators of gene expression through post-transcriptional regulation. However, the role of miRNAs in the neuroadaptations after alcohol removal has not yet been directly addressed. METHODS: We employed a chronic intermittent ethanol (CIE) model in primary cortical neuronal cultures to examine the global extent of differential miRNA expression using a TaqMan real-time PCR miRNA array. RESULTS: Sixty-two miRNAs were differentially expressed after 10 days of CIE (CIE10) treatment (n = 42 with false discovery rate [FDR] < 0.05 and fold change > 2) and 5 days post-CIE (P5) treatment (n = 26) compared with untreated control values. Compared to CIE10, ethanol (EtOH) removal experience in P5 induced a distinct expression pattern, including 20 differentially expressed miRNAs, which did not exhibit a significant change at CIE10. The predicted target molecules of EtOH removal-induced miRNAs function mainly in the regulation of gene transcription, but also function in neuron differentiation, embryonic development, protein phosphorylation, and synaptic plasticity. Interestingly, some of the miRNAs differentially expressed 5 days after CIE treatment were found to cluster on chromosomes near CpG islands, suggesting that they share functional similarity by targeting alcohol-related genes. CONCLUSIONS: Taken together, these results suggest a potential role of differentially expressed miRNAs in mediating EtOH removal-related phenotypes.
Asunto(s)
Depresores del Sistema Nervioso Central/farmacología , Corteza Cerebral/efectos de los fármacos , Etanol/farmacología , Regulación de la Expresión Génica/efectos de los fármacos , Expresión Génica/efectos de los fármacos , MicroARNs/efectos de los fármacos , Neuronas/efectos de los fármacos , Síndrome de Abstinencia a Sustancias/genética , Animales , Células Cultivadas , Islas de CpG , Perfilación de la Expresión Génica , Ratones , Ratones Endogámicos C57BL , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Síndrome de Abstinencia a Sustancias/metabolismoRESUMEN
Expression of the NMDA receptor 2B (NR2B) gene is upregulated following chronic intermittent ethanol (CIE) treatment and withdrawal, which underlies behavioral alterations in addiction. The goal of this study was to characterize the changes of histone modifications induced by CIE treatment and its subsequent removal associated to the upregulation of NR2B gene transcription. To investigate the involvement of histone acetylation in the effect of ethanol on the NR2B gene, we examined the influence of CIE on histone acetylation in the 5' regulatory region of NR2B using a qChIP assay. CIE treatment and its subsequent removal produced a remarkable and selected increase in histone H3K9 acetylation. Interestingly, the majority of the increased H3K9 acetylation occurred after ethanol removal, which was coincident with a decrease in H3K9 methylation in the same time duration. Further examination of the mechanisms of ethanol-induced alterations on the histone modifications revealed that CIE-induced acetylation of H3K9 was not due to the changes in global enzyme activities or the expression of histone acetyltransferases (HATs) and deacetylase (HDACs). Instead, we found a significant downregulation in some histone methyltransferases (HMTs) at both the global level and the local chromatin of the NR2B gene following CIE treatment. Moreover, our experiments also indicated a decrease of G9a, Suv39 h1 and HDAC1-3 in the chromatin of the NR2B gene promoter, which may be responsible for the altered H3K9 modifications. Taken together, the findings suggest a mechanism where the changes in H3K9 modifications in the local chromatin of the NR2B gene underlie alcohol-induced neuroadaptation.