Calcium-mediated aponecrosis plays a central role in the pathogenesis of estrogenic chemical-induced neurotoxicity

Effect of endocrine-disrupting chemicals on the expression of a calcium ion channel receptor (ryanodine receptor) in the mud crab (Macrophthalmus japonicus)

Endocrine-disrupting chemicals (EDCs) are toxic pollutants generated by artificial activities. Moreover, their hormone-like structure induces disturbances, such as mimicking or blocking metabolic activity. Previous studies on EDCs have focused on the adverse effect of the endocrine system in vertebrates, with limited investigations conducted on ion channels in invertebrates. Thus, in this study, we investigated the potential adverse effects of exposure to bisphenol-A (BPA) and di-(2-ethylhexyl) phthalate (DEHP) at the molecular level on the ryanodine receptor (RyR), a calcium ion channel receptor in Macrophthalmus japonicus. In the phylogenetic analysis, the RyR amino acid sequences in M. japonicus clustered with those in the Crustacean and formed separated branches for RyR in insects and mammals. When exposed to 1 μg L-1 BPA, a significant increase in RyR mRNA expression was observed in the gills on day 1, although a similar level to the control group was observed from day 4 to day 7. However, the RyR expression due to DEHP exposure decreased on days 1 and 4, although it increased on day 7 following exposure to 10 μg L-1. The RyR expression pattern in the hepatopancreas increased for up to 4 days, depending on the BPA concentration. However, there was a tendency for the expression to decrease gradually after the statistical significance increased during the early stage of DEHP exposure (D1). Hence, the transcriptional alterations in the M. japonicus RyR gene observed in the study suggest that exposure toxicities to EDCs, such as BPA and DEHP, have the potential to disrupt calcium ion channel signaling in the gills and hepatopancreas of M. japonicus crabs.

Microplastic polyamide toxicity: Neurotoxicity, stress indicators and immune responses in crucian carp, Carassius carassius

This study aimed to determine the toxicity standard and potential risks and effects of polyamide (PA) exposure on neurotoxicity, stress indicators, and immune responses in juvenile crucian carp Carassius carassius. Numerous microplastics (MPs) exists within aquatic environments, leading to diverse detrimental impacts on aquatic organisms. The C. carassius (mean weight, 23.7 ± 1.6 g; mean length, 13.9 ± 1.4 cm) were exposed to PA concentrations of 0, 4, 8, 16, 32 and 64 mg/L for 2 weeks. Among the neurotransmitters, the acetylcholinesterase (AChE) activity in the liver, gill, and intestine of C. carassius was significantly inhibited by PA exposure. Stress indicators such as cortisol and heat shock protein 70 (HSP70) in the liver, gill, and intestine of C. carassius were significantly increased, while immune responses to lysozyme and immunoglobulin M (IgM) were significantly decreased. Our study demonstrates the toxic effects of MP exposure on crucian carp's neurotoxicity, stress indicators, and immune responses.

Effects of common environmental endocrine-disrupting chemicals on zebrafish behavior

Environmental endocrine-disrupting chemicals (EDCs), a type of exogenous organic pollutants, are ubiquitous in natural aquatic environments. Therefor, this review focused on the use of the zebrafish as a model to explore the effect of different EDCs on behavior, as well as the molecular mechanisms that drive these effects. Furthermore, our study summarizes the current knowledge on the neuromodulatory effects of different EDCs in zebrafish. This study also reviews the current state of zebrafish behavior research, in addition to the potential mechanisms of single and mixed pollutant-driven behavioral dysregulation at the molecular level, as well as the applications of zebrafish behavior experiments for neuroscience research. This review broadens our understanding of the influence of EDCs on zebrafish behavior and provides guidance for future research.

Occurrence, fate and toxic effects of the industrial endocrine disrupter, nonylphenol, on plants - A review

Nonylphenol (NP) and its detrimental effects on the environment, humans, wildlife, fish and birds is an increasingly important global research focus. The number of investigations on the toxicity and metabolic fate of NP in plants is however limited. This paper reviews the prevalence and source of NP in plants and the effect it has on its morphological, physiological and ultrastructural status. Fruit and vegetables have been found to contain levels of NP that is twenty-fold exceeding the no observable effect level (NOEL) of freshwater algae. Apart from the potential risk this poses to the health of consumers, it can overburden the plant's natural defence system, leading to growth disorders. Plants exposed to NP show signs of overall growth reduction, changes in organelle structure and oxidative damage. These adverse effects may exacerbate the food security dilemma faced by many countries and impede their progress towards attaining the sustainable development goals.

Chlorinated biphenyls effect on estrogen-related receptor expression, steroid secretion, mitochondria ultrastructure but not on mitochondrial membrane potential in Leydig cells

To characterize polychlorinated biphenyls (PCBs) action on Leydig cells, PCBs congeners, low-chlorinated (delor 103; d103) and high-chlorinated ones (delor 106; d106) were selected. The cells were treated according to PCBs dose (d103 or d106 0.2 ng/ml in low doses:, or 2 ng/ml in high doses) and type (d103 + d106 in low doses or 103 + 106 in high doses). After 24 h treatment with PCBs, a distinct increase in estrogen-related receptors (ERRs type α, β and γ) expression was revealed. However, the dose- and type-dependent PCBs effect was mostly exerted on ERRα expression. A similar increase in ERRs expression was demonstrated by estradiol but not testosterone, which was without an effect on ERRs. PCBs caused no decrease in the membrane potential status of Leydig cells (either in dose or type schedule) but had severe effects on the mitochondria number and structure. Moreover, PCBs markedly increased calcium (Ca2+) concentration and sex steroid secretion (both androgens and estrogens were elevated). These findings suggest a similar estrogenic action of PCBs congeners (d103 and d106) on Leydig cell function. We report dose- and type-specific effects of PCBs only on Leydig cell ERRs expression. Both delors showed common effects on the mitochondria ultrastructural and functional status. Based on our results, ERRα seems to be the most sensitive to hormonal modulation. The increases in Ca2+ and sex steroid secretion may be due to the activation of ERRs by PCBs binding and/or direct effect of PCBs on ERRs mRNA/protein expression. Nevertheless, to confirm the existence of possible relationships between ERRs signaling (including PCBs as ligands) and mitochondria function in Leydig cells, further intensive studies are needed.

The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

The mitochondrial calcium uniporter (MCU)-a calcium uniporter on the inner membrane of mitochondria-controls the mitochondrial calcium uptake in normal and abnormal situations. Mitochondrial calcium is essential for the production of adenosine triphosphate (ATP); however, excessive calcium will induce mitochondrial dysfunction. Calcium homeostasis disruption and mitochondrial dysfunction is observed in many neurodegenerative disorders. However, the role and regulatory mechanism of the MCU in the development of these diseases are obscure. In this review, we summarize the role of the MCU in controlling oxidative stress-elevated mitochondrial calcium and its function in neurodegenerative disorders. Inhibition of the MCU signaling pathway might be a new target for the treatment of neurodegenerative disorders.

Elucidating a molecular mechanism that the deterioration of porcine meat quality responds to increased cortisol based on transcriptome sequencing

Stress response is tightly linked to meat quality. The current understanding of the intrinsic mechanism of meat deterioration under stress is limited. Here, male piglets were randomly assigned to cortisol and control groups. Our results showed that when serum cortisol level was significantly increased, the meat color at 1 h postmortem, muscle bundle ratio, apoptosis rate, and gene expression levels of calcium channel and cell apoptosis including SERCA1, IP3R1, BAX, Bcl-2, and Caspase-3, were notably increased. However, the value of drip loss at 24 h postmortem and serum CK were significantly decreased. Additionally, a large number of differentially expressed genes (DEGs) in GC regulation mechanism were screened out using transcriptome sequencing technology. A total of 223 DEGs were found, including 80 up-regulated genes and 143 down-regulated genes. A total of 204 genes were enriched in GO terms, and 140 genes annotated into in KEGG database. Numerous genes were primarily involved in defense, inflammatory and wound responses. This study not only identifies important genes and signalling pathways that may affect the meat quality but also offers a reference for breeding and feeding management to provide consumers with better quality pork products.

Insecticide cytotoxicology in China: Current status and challenges

The insecticide cytotoxicology, as a new branch of toxicology, has rapidly developed in China. During the past twenty years, thousands of investigations have sprung up to evaluate the damages and clarify the mechanisms of insecticidal chemical substances to insect cells in vivo or in vitro. The mechanisms of necrosis, apoptosis or autophagy induced by synthetic or biogenic pesticides and virus infections have been systematically illuminated in many important models, including S2, BmN, SL-1, Sf21 and Sf9 cell lines. In addition, a variety of methods have also been applied to examine the effects of insecticides and elaborate the modes of action. As a result, many vital factors and pathways, such as cytochrome c, the Bcl-2 family and caspases, in mitochondrial signaling pathways, intracellular free calcium and lysosome signal pathways have been illuminated and drawn much attention. Benefiting from the application of insecticide cytotoxicology, natural products purifications, biological activities assessments of synthetic compounds and high throughput screening models have been accelerated in China. However, many questions remained, and there exist great challenges, especially in theory system, evaluation criterion, evaluation model, relationship between activity in vitro and effectiveness in vivo, and the toxicological mechanism. Fortunately, the generation of "omics" could bring opportunities for the development of insecticide cytotoxicology.

Effect of maternal morphine sulfate exposure on neuronal plasticity of dentate gyrus in Balb/c mice offspring

This study carried out to evaluate the effects of maternal morphine exposure during gestational and lactation period on the neuronal cells of dentate gyrus in 18 and 32 days Balb/c mice offspring. In this experimental study 10 female mice were randomly allocated into cases and controls. In experimental group, animals were received morphine sulfate 10 mg/kg/body weight intraperitoneally during 7 days before mating, gestational period (GD0-21), 18 and 32 days after delivery. The control animals were received an equivalent volume normal saline. Cerebrum of six infant for each group were removed and stained with cresyl violet and monoclonal anti-neuronal nuclei (NeuN) antibody. Quantitative computer-assisted morphometric study was done on dentate gyrus of hippocampus. In the P18 mice, the numbers of granular cells in dentate gyrus medial blade and dentate gyrus lateral blade significantly reduced from 171.45 +/- 4.2 and 174.51 +/- 3.1 cells in control group to 153.32 +/- 2.8 and 151.23 +/- 3.2 cells in 10000 microm2 area of granular layer in treated group (p < 0.001). In P32 mice the numbers of granular cells in mb and lb of dentate gyrus significantly decreased from 155.31 +/- 4.1 and 153.77 +/- 3.4 in control group to 138.33 +/- 4.5 and 135.13 +/- 4.3 in treated group, respectively (p < 0.001). The granular layer thickness in mb and lb area of dentate gyrus significantly reduced in treated mice in compared to controls in P18 and P32 mice (p < 0.05). This study revealed that morphine administration before, during pregnancy and lactation period causes neuronal cells loss of dentate gyrus in 18 and 32 days old infant mice.

The use of the urogenital papillae of male feral African sharptooth catfish (Clarias gariepinus) as indicator of exposure to estrogenic chemicals in two polluted dams in an urban nature reserve, Gauteng, South Africa

The African sharptooth catfish (Clarias gariepinus) is indigenous to South Africa where it is commonly found in calm waters such as lakes, streams, rivers, swamps and floodplains. The males of this gonochoristic species can be readily distinguished from females via a distinct elongated urogenital papilla with a pointed tip, located just behind the anus. This structure is an androgen controlled secondary sexual characteristic and could potentially be affected by chemicals displaying endocrine disrupting properties during development. Results of previous studies on effects on papillae of different fish species indicated that these structures could be useful as bio-indicators of exposure due to alterations in the structures. This study investigated the occurrence of abnormal morphology in urogenital papillae compared to the macroscopic and microscopic structure of the gonads of presumed male or intersex catfish sampled from the Rietvlei and Marais dams in an urban nature reserve, due to exposure to endocrine disrupting chemicals (EDCs). Macroscopic observation of the UGP, gonad examination after laparotomy and histology were done. Gonadosomatic index (GSI) and Urogenital papilla length index (UGPLI) were determined for all fish collected. Mesenteric fat analyzed for selected alkylphenols and organochlorines showed high levels of especially nonylphenol indicating long term exposure to these chemicals due to bio-accumulation. The GSI indicated that fish with intersex gonads were probably feminized males. It was concluded that use of the UGP alone, without macroscopic and microscopic analyses of the gonads, could not effectively indicate exposure to EDCs.

Purkinje cells loss in off spring due to maternal morphine sulfate exposure: a morphometric study

The toxic effects of morphine sulfate in the adult cerebral cortex and one-day neonatal cerebellum have been studied. This study was carried out to evaluate the effect of maternal morphine exposure during gestational and lactation period on the Purkinje cells and cerebellar cortical layer in 18- and 32-day-old mice offspring. Thirty female mice were randomly allocated into cases and controls. In cases, animals received morphine sulfate (10 mg/kg/body weight intraperitoneally) during the 7 days before mating, gestational day (GD 0-21) 18 or 32. The controls received an equivalent volume of saline. The cerebellum of six infants for each group was removed and each was stained with cresyl violet. Quantitative computer-assisted morphometric study was done on cerebellar cortex. The linear Purkinje cell density in both experimental groups (postnatal day [P]18, 23.40±0.5; P32, 23.45±1.4) were significantly reduced in comparison with the control groups (P18, 28.70±0.9; P32, 28.95±0.4) (P<0.05). Purkinje cell area, perimeter and diameter at apex and depth of simple lobules in the experimental groups were significantly reduced compared to the controls (P<0.05). The thickness of the Purkinje layer of the cerebellar cortex was significantly reduced in morphine treated groups (P<0.05). This study reveals that morphine administration before pregnancy, during pregnancy and during the lactation period causes Purkinje cells loss and Purkinje cell size reduction in 18- and 32-day-old infant mice.

Induction of intracellular Ca2+ and pH changes in Sf9 insect cells by rhodojaponin-III, a natural botanic insecticide isolated from Rhododendron molle

Many studies on intracellular calcium ([Ca²⁺]_i) and intracellular pH (pH_i) have been carried out due to their importance in regulation of different cellular functions. However, most of the previous studies are focused on human or mammalian cells. The purpose of the present study was to characterize the effect of Rhodojaponin-III (R-III) on [Ca²⁺]_i and pH_i and the proliferation of Sf9 cells. R-III strongly inhibited Sf9 cells proliferation with a time- and dose-dependent manner. Flow cytometry established that R-III interfered with Sf9 cells division and arrested them in G2/M. By using confocal scanning technique, effects of R-III on intracellular free calcium ([Ca²⁺]_i) and intracellular pH (pH_i) in Sf9 cells were determined. R-III induced a significant dose-dependent (1, 10, 100, 200 μg/mL) increase in [Ca²⁺]_i and pH_i of Sf9 cells in presence of Ca²⁺-containing solution (Hanks) and an irreversible decrease in the absence of extra cellular Ca²⁺. We also found that both extra cellular Ca²⁺ and intracellular Ca²⁺ stores contributed to the increase of [Ca²⁺]_i, because completely treating Sf9 cells with CdCl₂ (5 mM), a Ca²⁺ channels blocker, R-III (100 μg/mL) induced a transient elevation of [Ca²⁺]_i in case of cells either in presence of Ca²⁺ containing or Ca²⁺ free solution. In these conditions, pH_i showed similar changes with that of [Ca²⁺]_i on the whole. Accordingly, we supposed that there was a certain linkage for change of [Ca²⁺]_i, cell cycle arrest, proliferation inhibition in Sf9 cells induced by R-III.

Histopathological and biochemical changes of morphine sulphate administration on the cerebellum of albino rats

In this study the long-term effects of morphine sulphate treatment (MST) on histopathological and biochemical changes in the cerebellum was assessed in albino rats. Normal saline (5ml) was given orally as placebo in the control group (n=25). Morphine groups received morphine orally at a dose level of 5mg/kg body weight day after day for 10, 20 and 30 days (n=25/group). Light microscopy revealed that the molecular layer showed vacuolation. The Purkinje cells lost their specific shaped appearance, decreased in size and numbers. The granular cells highly degenerated. Electron microscopy revealed fragmentation of the cisterns of the both types of endoplasmic reticulum, resulted in a progressive depletion of total protein contents as well as general carbohydrates in all treated groups as supported by histochemical observation. Obvious destruction of mitochondrial inner membrane and cristae mediate cell death. Also, abnormal nucleus with deformed perforated nuclear membrane and deformation of the plasma membrane with degeneration of the synapses could interpreted as a sign of necrosis. Biochemical analysis revealed that dopamine (DA) and norepinephrine (NE) were significantly decreased in four brain areas (cortex striatum, thalamus/hypothalamus, and cerebellum). In contrast, serotonin (5-HT) level was increased in these brain regions; with an exception of 5-HT on day 10 and neurotransmitter levels in the pons were unaffected. The quantitative analysis showed a significant decrease (P<0.05) in the diameter of Purkinje cells and in the thickness of both molecular and granular layers treated groups. Morphine sulphate induces may be a cell death or necrosis in the rat cerebellum and modulating neurotransmitter system. Our findings pointed out the risk of increased cerebellum damage due to long-term of morphine use.

Induction of Ca2+ signal mediated apoptosis and alteration of IP3R1 and SERCA1 expression levels by stress hormone in differentiating C2C12 myoblasts

Glucocorticoid (GC) are stress hormones, whose cytotoxicity has been shown in various cells. The imbalance of calcium homeostasis is believed to be associated with the dexamethasone (DEX, a synthetic GC)-induced apoptosis. Here we show that in C2C12 myoblasts, DEX markedly up-regulated the expression of inositol 1,4,5-triphosphate receptor 1 (IP3R1) and down-regulated the expression of SERCA1 (sarcoendoplasmic reticulum Ca(2+)-ATPase 1), leading to calcium overload. Furthermore, the imbalance of calcium homeostasis increased the level of BAX, decreased the level of Bcl-2, induced cytochrome c release and activated caspase-3, leading to intranucleosomal DNA fragmentation and plasma membrane damage, eventually resulting in cell apoptosis. Taken together, by using C2C12 myoblasts as a model system, we demonstrated a novel mechanism for stress hormone-induced apoptosis: it is dependent on the induction of intracellular calcium overload via the alterations of IP3R1 and SERCA1 expressions.

Ultrastructural effects of DDT, DDD, and DDE on neural cells of the chicken embryo model

Human exposure to environmental compounds with estrogenic activity and the potential effects on human health is the subject of ongoing scientific debates. Their potential effects raise concern regarding neurological development after prenatal exposure. Central to this debate is the pesticide 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT). Although it has apparent low acute toxicity in mammals, DDT has a long residual persistence and laboratory research has indicated that it acts on the CNS by interfering with Na(+)/K(+) pump mechanism of the neuronal membranes, causing disruption in Ca(2+) homeostasis. Potentially this may lead to both apoptosis and necrosis. The present study investigates the effects of DDT and two of its metabolites DDD and DDE on the ultramorphology of neural cells, using a previously published chicken embryo model. Results indicate cellular swelling, budding, and increased membrane permeability for all three chemicals, accompanied by karyolysis in the DDE group (typical features of oncosis). These results support the finding of other researchers as well as the concerns of the WHO that DDT and its metabolites may cause neurotoxicity after prenatal exposure.

Effect of solanine on the membrane potential of mitochondria in HepG2 cells and [Ca2+]i in the cells

AIM: To observe the effect of solanine on the membrane potential of mitochondria in HepG₂ cells and [Ca²⁺]_i in the cells, and to uncover the mechanism by which solanine induces apoptosis.

METHODS: HepG₂ cells were double stained with AO/EB, and morphological changes of the cells were observed using laser confocal scanning microscopy (LCSM). HepG₂ cells were stained with TMRE, and change in the membrane potential of mitochondria in the cells were observed using LCSM. HepG₂ cells were double stained with Fluo-3/AM, and change of [Ca²⁺]_i in the cells were observed using LCSM. HepG₂ cells were double stained with TMRE and Fluo-3/AM, and both the change in membrane potential of mitochondria and that of [Ca²⁺]_i in the cells were observed using LCSM.

RESULTS: Cells in treated groups showed typical signs of apoptosis. Staining with TMRE showed that solanine could lower membrane potential; staining with Fluo-3/AM showed that solanine could increase the concentration of Ca²⁺ in tumor cells; and those of double staining with TMRE and Fluo-3/AM showed that solanine could increase the concentration of Ca²⁺ in the cells at the same time as it lowered the membrane potential of mitochondria.

CONCLUSION: Solanine opens up the PT channels in the membrane by lowering the membrane po-tential, leading to Ca²⁺ being transported down its concentration gradient, which in turn leads to the rise of the concentration of Ca²⁺ in the cell, turning on the mechanism for apoptosis.