Effects Of Butyl Benzyl Phthalate Research Articles

Butyl benzyl phthalate induced reproductive toxicity in the endoplasmic reticulum and oxidative stress in Brachionus plicatilis Müller, 1786

To study the adverse effects of butyl benzyl phthalate (BBP) on Brachionus plicatilis, rotifers were exposed to different BBP concentrations (0 [control], 0.001, 0.01, 0.1, and 1 mg/L). We measured the activities of the antioxidant enzymes superoxide dismutase, catalase, and reduced glutathione, which play a key role in detoxification, and the malondialdehyde content, which represents the level of lipid peroxidation. In addition, we investigated the effect of BBP on the submicroscopic structure and transcriptome of rotifer ovary cells. Our results showed that B. plicatilis exhibited a rapid oxidative stress response accompanied by a significant increase in superoxide dismutase enzyme activity. High BBP concentrations resulted in a significant decrease in malondialdehyde content, which indicated that BBP interferes with the lipid metabolism of rotifer cells. Our observations showed that the endoplasmic reticulum structure of rotifer ovary cells was severely damaged by BBP exposure. Transcriptomic data further demonstrated that oxidative stress and cellular sub-microstructural damage were associated with altered expression of functional genes related to rotifer redox regulation, biosynthetic processes, and cellular damage components. In conclusion, our study demonstrates that BBP triggers changes in antioxidant-related indicators in rotifers; this leads to activation of related genes and subsequent changes in intracellular signaling, which in turn triggers endoplasmic reticulum stress and ultimately leads to disruption of cell function and structure. These findings highlight the potential risks associated with BBP exposure and provide fundamental insights into its toxicological effects on marine invertebrates.

Effects of butyl benzyl phthalate on zebrafish (Danio rerio) brain and the underlying molecular mechanisms revealed by transcriptome analysis

Butyl benzyl phthalate (BBP), a widely used class of plasticizers, has caused considerable concerns due to its widespread detection in various environmental media. However, the potential impact of BBP on the brain and its underlying molecular mechanisms remain poorly understood. In this study, adult zebrafish (Danio rerio) were exposed to 0, 5, 50, and 500 μg/L BBP for 28 days. Elevated levels of both reactive oxygen species and 8-hydroxydeoxyguanosine were observed, indicating the occurrence of oxidative stress and DNA damage. Furthermore, exposure to BBP resulted in neurotoxicity, apoptosis, and histopathological damage within the zebrafish brain. Transcriptome analysis further revealed that Gene Ontology terms associated with muscle contraction were specifically expressed in the brain after BBP exposure. In addition, BBP altered the transcriptome profile of the brain, with 293 genes induced and 511 genes repressed. Kyoto Encyclopedia of Genes and Genomes analysis highlighted the adverse effects of BBP on the complement and coagulation cascades and two cardiomyopathy-related pathways. Taken together, our results revealed that BBP resulted in brain oxidative stress, histological damage, and transcriptome alterations. These findings have the potential to offer novel insights into the adverse outcome pathways of key events in the brain.

Effects of butyl benzyl phthalate exposure during pregnancy and lactation on the post-involution mammary gland

The mammary gland undergoes comprehensive reorganization during pregnancy, lactation, and subsequent involution. Following involution, the mammary gland has structural and functional differences compared to the gland of a nulliparous female. These parity-associated changes are regulated by hormones and may be vulnerable to endocrine-disrupting chemicals (EDCs). In this study, we evaluated the long-term effects of butyl benzyl phthalate (BBP), an estrogenic plasticizer, on the parous mouse mammary gland. Pregnant BALB/c mice were treated with 0, 3, 500, or 18000 µg/kg/day BBP throughout both pregnancy and the lactational period. The litters born to these females were evaluated for litter size and growth. The parous females were then kept for five weeks following weaning of the pups, during which period there was no exposure to BBP. After five weeks of post-weaning, mammary glands were collected and assessed for changes in histomorphology, steroid receptor expression, innate immune cell number, and gene expression. An unexposed age-matched nulliparous control was also evaluated as a comparator group. BBP increased male and female pup weight at puberty and female offspring in adulthood. BBP also altered innate immune cells in the post-involution mammary gland, reducing the effect of parity on macrophages. Lastly, BBP modestly increased mammary gland ductal complexity and periductal structure, but had no effect on expression of estrogen receptor, progesterone receptor, or a marker of proliferation. These results suggest that BBP may interfere with some effects of parity on the mouse mammary gland and induce weight gain in exposed offspring.

Co-exposure effects of butyl benzyl phthalate and TiO2 nanomaterials (anatase) on Metaphire guillelmi gut health

Phthalic acid esters (PAEs) and TiO2 nanomaterials (nTiO2) are commonly used as plastic additives, nano-fertilizers or nano-pesticides. Their excessive co-applications led to the co-occurrence, which can induce damage to soil organisms such as Metaphire guillelmi (an earthworm widespread in farmland). However, the co-exposure effects of butyl benzyl phthalate (BBP, a typical PAEs) and nTiO2 on Metaphire guillelmi at environmental-relevant concentrations remain unclear. In this study, 1 mg kg−1 BBP and 1 mg kg−1 nTiO2 (anatase) were added into the soil to assess: (1) their effects on oxidative damage, digestive system, and neurotoxicity in Metaphire guillelmi gut on days 14 and 28; and (2) whether BBP and nTiO2 affected Metaphire guillelmi gut health by disrupting intestinal microorganisms. The results demonstrated that BBP and nTiO2 had the potential to inhibit the activity of superoxide dismutase, cellulase, protease, Na+K+-ATPase, and Ca2+-ATPase, as well as cause oxidative damage by altering intestinal bacteria such as Marmoricola and Microvirga at genus levels after 28 d-exposure. However, the exposure did not cause disorders of the intestinal bacteria. The present study provides more evidence for the sustainable application and scientific management of BBP and nTiO2, thus providing better guidance for PAEs and engineered nanomaterials regulations in agroecosystems.

Silibinin supplementation ameliorates the toxic effects of butyl benzyl phthalate on porcine oocytes by eliminating oxidative stress and autophagy

Butyl benzyl phthalate (BBP) is a common environmental pollutant, it is high in paints, adhesives and other decorative materials, food packaging bags, cleaning agents, is a plasticizer is very widely used in daily life. However, it remains unknown whether BBP causes damage to oocytes cultured in vitro and whether there is an effective rescue strategy. Here, we evaluated the effects of exposure to different concentrations of BBP (10, 50, and 100 μM) on the meiosis of porcine oocytes. The results showed that exposure to BBP (100 μM) severely impaired expansion of cumulus-oocyte complex (COCs) and PBE (control:71.6% vs 100 μM: 48.8%). Spindle conformation and chromosome alignment were also significantly abnormal (34.8% and 46.0%, respectively) compared to the control (11.1% and 17.5%, respectively), and BBP caused damage to microfilaments and cortical granules (CGs). In addition, oocyte exposure to BBP induced impaired mitochondrial function and disrupted mitochondrial integrity. Silibinin is a natural active substance isolated from the seeds of Silybum marianum (L.) Gaertneri with strong antioxidant and anti-inflammatory effects. Noteworthy, we added different concentrations of silibinin (10, 20, and 50 μM) to BBP-exposed oocytes for rescue experiments, where 50 μM effectively rescued BBP-induced meiotic failure (70.6%). It also prevented the generation of excessive autophagy and apoptosis in oocytes by inhibiting the production of ROS. In a word, our results suggest that supplementation of silibinin attenuates the impaired oocyte development caused by BBP exposure，which provides a potential strategy to protect oocytes from environmental pollutants.

Butyl Benzyl Phthalate in Urban Sewage by Magnetic-Based Immunoassay: Environmental Levels and Risk Assessment.

A magnetic-based immunoassay (MBI) combined with biotin-streptavidin amplification was proposed for butyl benzyl phthalate (BBP) investigation and risk assessment. The values of LOD (limit of detection, IC10) and IC50 were 0.57 ng/mL and 119.61 ng/mL, with a detection range of 0.57–24,977.71 ng/mL for MBI. The specificity, accuracy and precision are well demonstrated. A total of 36 environmental water samples of urban sewage from Zhenjiang, China, were collected and assessed for BBP contamination. The results show that BBP-positive levels ranged from 2.47 to 89.21 ng/mL, with a positive rate of 77.8%. The health effects of BBP in the urban sewage were within a controllable range, and the ambient severity for health (ASI) was below 1.49. The highest value of AS for ecology (ASII) was 7.43, which indicates a potential harm to ecology. The entropy value of risk quotient was below 100, the highest being 59.47, which poses a low risk to the environment and ecology, indicating that there is a need to strengthen BBP controls. The non-carcinogenic risk of BBP exposure from drinking water was higher for females than that for males, and the non-carcinogenic risk from drinking-water and bathing pathways was negligible. This study could provide an alternative method for detecting BBP and essential information for controlling BBP contamination.

Growth‐promoting effects of low‐level butyl benzyl phthalate exposure on human neuroblastoma SH‐SY5Y cells

The purpose of present study was to investigate the impact of butyl benzyl phthalate (BBP) on SH-SY5Y neuroblastoma cells in vitro. The cell counting kit-8 was used to measure cell proliferation and flow cytometry was utilized to study cell cycle phases and apoptosis. Western blotting and quantitative real-time polymerase chain reaction were used to detect levels of aromatase, estrogen receptors (ERs) and some apoptosis and cell cycle-related genes. Results showed BBP-stimulated SH-SY5Y cells in a dose-dependent manner and produced a reverted U-shaped dose-response curve. BBP at lower concentrations (0.01 and 0.1μm) significantly induced cell proliferation while inhibited cell growth at 300μm. The promoting effect of estradiol could be entirely blocked by administration of ICI182780, a pure antagonist of ERs, while the effect of BBP could be partly blocked. Additionally, we confirmed 0.1μm BBP-induced cell proliferation caused the arrest of cells in S phase and inhibited apoptosis, which might be partially explained by the decreased expression of p53, the increased expression of proliferating cell nuclear antigen, Bcl-2 and cell cycle regulator cyclin-D1, and the activation of aromatase. The addition of ICI182780 had no effect on BBP-induced ERβ mRNA expression, whereas ICI182780 could effectively counteract the effect of estradiol. Moreover, pretreatment with ICI182780 could block the induction of aromatase protein expression and activity by BBP, showing an involvement of ERs. Except for the ER pathway, these results showed there might be other pathways involved in promoting the effects of low-level BBP on SH-SY5Y cells, which require further investigation.

Developmental toxicity and cardiac effects of butyl benzyl phthalate in zebrafish embryos

Phthalic acid esters (PAEs), commonly called phthalates, have become ubiquitous environment pollutants. Studies have focused on reproductive toxicity, neurotoxicity, teratogenicity, tumourigenesis, and mutagenesis of phthalates. However, relatively little is known about the phthalates effects on the heart. Butyl benzyl phthalate (BBP), a member of PAEs, is classified by the US Environmental Protection Agency as a priority environmental pollutant. We studied the developmental toxicity of BBP, especially its effects on the heart development, in zebrafish (Danio rerio) embryos. Embryos at 4hr post-fertilization (hpf) were exposed to 0, 0.1, 0.6 and 1.2mg/L BBP until 72hpf. BBP caused abnormalities in embryo morphology, including yolk-sac edema, spinal curvature, tail deformity, uninflated swim bladder and cardiac defects. Exposure to 0.6mg/L BBP significantly increased the malformation rate, caused growth inhibition, increased the cardiac malformation rate as well as the distance between the sinus venosus (SV) and bulbus arteriosus (BA), and reduced the heart rate of embryos. Exposure to 1.2mg/L BBP significantly affected all endpoints, except survival rate at 24hpf. To preliminarily elucidate the potential mechanism of heart developmental toxicity caused by BBP, we examined the expression of two genes related to heart development, Nkx2.5 and T-box transcription factor 5, by real-time quantitative PCR. The expression of the two genes was dose-dependently downregulated with BBP. BBP could induce developmental toxicity, with adverse effects on the heart development in zebrafish embryos, and alter the expression of genes related to heart development.

Benzyl butyl phthalate decreases myogenic differentiation of endometrial mesenchymal stem/stromal cells through miR-137-mediated regulation of PITX2

Phthalate, an environmental toxin, has been considered as an endocrine-disrupting chemical. Growing evidence has demonstrated links between endocrine-disrupting chemicals, tissue development, and reproductive physiology, but the mechanisms of gene expression regulation by environmental factors that affect cell differentiation are unclear. Herein, we investigated the effects of butyl benzyl phthalate (BBP) on human endometrial mesenchymal stem/stromal cell (EN-MSC) differentiation and identified a novel signaling pathway. Differentiation of endometrial mesenchymal stem/stromal cells decreased after administration of BBP. We analyzed BBP regulation of gene expression in EN-MSC using cDNA microarrays and Ingenuity Pathway Analysis software to identify affected target genes and their biological functions. PITX2 emerged as a common gene hit from separate screens targeting skeletal and muscular disorders, cell morphology, and tissue development. BBP decreased transcription of PITX2 and elevated expression of the microRNA miR-137, the predicted upstream negative regulator of PITX2. These data indicated that BBP affects PITX2 expression through miR-137 targeting of the 3′ untranslated region of PITX2 mRNA. PITX2 down-regulation also decreased MyoD transcript levels in EN-MSC. Our results demonstrate that BBP decreases EN-MSC myogenic differentiation through up-regulation of miR-137, contribute to our understanding of EN-MSC differentiation, and underline the hazardous potential of environmental hormones.

Regulation of mRNA Translation Is a Novel Mechanism for Phthalate Toxicity

Phthalates are a group of plasticizers that are widely used in many consumer products and medical devices, thus generating a huge burden to human health. Phthalates have been known to cause a number of developmental and reproductive disorders functioning as endocrine modulators. They are also involved in carcinogenesis with mechanisms less understood. To further understand the molecular mechanisms of phthalate toxicity, in this study we reported a new effect of phthalates on mRNA translation/protein synthesis, a key regulatory step of gene expression. Butyl benzyl phthalate (BBP) was found to directly inhibit mRNA translation in vitro but showed a complicated pattern of affecting mRNA translation in cells. In human kidney embryonic cell (HEK-293T), BBP increased cap-dependent mRNA translation at lower concentrations but showed inhibitory effect at higher concentrations. Cap-independent translation was not affected. On the other hand, mono (2-ethylhexyl) phthalate (MEHP) as a major metabolite of another important phthalate di (2-ethylhexyl) phthalate (DEHP) inhibited both can-dependent and -independent mRNA translation in vivo. In contrast, BBP and MEHP exhibited an overall promoting effect on mRNA translation in cancer cells. Mechanistic studies identified that the level and phosphorylation of eIF4E-BP (eIF4E binding protein) and the amount of eIF4GI in eIF4F complex were altered in accordance with the effect of BBP on translation. BBP was also identified to directly bind to eIF4E, providing a further mechanism underlying the regulation of mRNA by phthalate. At the cellular level BBP inhibited normal cell growth but slightly promoted cancer cells (HT29) growth. Overall, this study provides the first evidence that phthalates can directly regulate mRNA translation as a novel mechanism to mediate their biological toxicities.

Effect of Butyl Benzyl Phthalate on Male Reproductive and Developmental Toxicity

邻苯二甲酸丁基苄酯(BBP)是邻苯二甲酸酯的一种, 作为常用的增塑剂和溶剂, 广泛应用于医疗、化工、食品、装修材料等产品, 并在环境介质及人体中广泛检出. BBP被认为具有类雌激素作用, 具有一定的生殖发育毒性. 本文主要对BBP的代谢暴露水平、BBP及其主要代谢产物在雄性生殖发育毒性方面的研究进展进行了综述.

Influence of BBP exposure on nervous system and antioxidant system in zebrafish.

In order to observe the toxic effects of butyl benzyl phthalate (BBP) on zebrafish, the AChE and SOD activity of zebrafish exposed to different concentrations of BBP (0, 0.332, 0.665, 1.33 mg L(-1)) in a short-term (7d) test were determined. Semi-quantitative PCR was used to determine the mRNA transcript levels of the AChE and SOD gene in zebrafish brain and muscle. The results showed: AChE activity decreased with increased exposure concentration, and was significantly inhibited (p < 0.01) compared with the control group at 0.665 mg L(-1) concentration. Low BBP concentrations stimulated and high concentrations inhibited SOD activity with a concentration of 0.332 mg L(-1) resulting in a significant induction (p < 0.05) compared with the control, and 0.665 and 1.33 mg L(-1) concentrations resulting in significant inhibition (p < 0.05, p < 0.01) relative to the control group. The RT-PCR data showed a decrease in brain and muscle mRNA transcription of AChE gene with an increase in exposure concentration. The mRNA transcription of SOD in the brain was not different between the exposed groups and control group; in muscle, the mRNA transcription inhibition decreased and then increased: all differences from the control were statistically significant.

Impact of butyl benzyl phthalate on development of the reproductive system of European pikeperch, Sander lucioperca (L.)

The effect of butyl benzyl phthalate (BBP) on the sex differentiation process of fish is practically unknown. The experimental material of this study was juvenile European pikeperch [Sander lucioperca (L.)], which is gonochoristic, undergoes immediate sex differentiation, and has a fixed gonad differentiation period. The fish were fed a diet supplemented with BBP (during the sex differentiation phase: age 61-96 days post hatch) in the following quantities: 1.0; 2.0; 4.0; 8.0; 16.0 g BBP kg-1 feed. The control feed was a xenobiotic-free base feed. In the present experiment lasting 10 weeks, the survival and growth of fish, the histopathological changes of the fish gonads and the sex ratio were evaluated. After administration of the two highest doses of BBP, growth inhibition of the fish was observed. BBP also seriously disturbed the gonadal differentiation process of pikeperch. All analysed concentrations of BBP delayed testicular development and, at concentrations of 4.0, 8.0 and 16.0 g BBP kg-1, induction of the feminisation process was observed. The sex ratio was distinctly disrupted in groups receiving 8.0 and 16.0 g BBP kg-1.

环境激素邻苯二甲酸丁基苄酯对家蚕生殖的影响

This study aims to determine the effects of the environmental hormone butyl benzyl phthalate( BBP) on the genital development of the silkworm Bombyx mori. Larvae were fed with different concentrations of BBP at different developmental stages. The numbers of mature eggs produced and laid were recorded,and the genital development was observed. The body weight,survival rate,and egg production were greatly influenced by BBP concentration. In newly molted fifth larva fed with 1.6 mmol /L BBP,56.1% and 51.4% of mature eggs were produced and laid,respectively,as compared with the controls. The fertilization rate and hatchability of the silkworm showed similar tendencies. The effects of BBP were greater on males than on females. The effects of BBP on the different life stages of silkworm were arranged as follows: newly molted third larva newly molted fourth larva newly molted fifth larva. For newly molted third,fourth,and fifth larvae fed with 0.16 mmol /L BBP,57.5%,63.3%,97.6% of mature eggs were produced,respectively,and 58.7%,74.1%,96.0% of mature eggs were laid,respectively,as compared with the controls. No evident effects on the cocoon quality of the following generations were observed. BBP,which can accumulate in the silkworm body,has significant detrimental effects on genital development. The earlier the larvae were fed with BBP and the higher the BBP concentration,the greater the biological effects.

Comparative effects of butyl benzyl phthalate (BBP) and di(2-ethylhexyl) phthalate (DEHP) on the aquatic larvae of Chironomus riparius based on gene expression assays related to the endocrine system, the stress response and ribosomes

In this work, the effects of butyl benzyl phthalate (BBP) and di(2-ethylhexyl) phthalate (DEHP), two of the most extensively used phthalates, were studied in Chironomus riparius under acute short-term treatments, to compare their relative toxicities and identify genes sensitive to exposure. The ecotoxicity of these phthalates was assessed by analysis of the alterations in gene expression profiles of selected inducible and constitutive genes related to the endocrine system, the cellular stress response and the ribosomal machinery. Fourth instar larvae, a model system in aquatic toxicology, were experimentally exposed to five increasing concentrations (0.01, 0.1, 1, 10, and 100 mg/L) of DEHP and BBP for 24 h. Gene expression was analysed by the changes in levels of transcripts, using RT-PCR techniques with specific gene probes. The exposures to DEHP or BBP were able to rapidly induce the hsp70 gene in a concentration-dependent manner, whereas the cognate form hsc70 was not altered by either of these chemicals. Transcription of ribosomal RNA as a measure of cell viability, quantified by the levels of ITS2, was not affected by DEHP, but was slightly, yet significantly, downregulated by BBP at the highest concentrations tested. Finally, as these phthalates are classified as endocrine disruptor chemicals (EDCs), their potential effect on the ecdysone endocrine system was studied by analysing the two genes, EcR and usp, of the heterodimeric ecdysone receptor complex. It was found that BBP provoked the overexpression of the EcR gene, with significant increases from exposures of 0.1 mg/L and above, while DEHP significantly decreased the activity of this gene at the highest concentration. These data are relevant as they show for the first time the ability of phthalates to interfere with endocrine marker genes in invertebrates, demonstrating their potential capacity to alter the ecdysone signalling pathway. Overall, the study clearly shows a differential gene–toxin interaction for these two phthalates and adds novel genomic tools for biomonitoring environmental xenobiotics in insects.

Proteomic Analysis of Proteins Secreted by HepG2 Cells Treated with Butyl Benzyl Phthalate

Proteomic changes in proteins secreted by human hepatocellular carcinomas (HepG2) cells exposed to butyl benzyl phthalate (BBP) were evaluated. HepG2 cells were treated with three different concentrations of BBP (0, 10, or 25 μM) for 24 or 48 h. Following incubation, the cells were subjected to proteomic analysis using two different pI ranges (4–7 and 6–9) and large-size two-dimensional gel electrophoresis. Results showed resolution of a total of 2776 protein spots. Of these, 29, including 19 upregulated and 10 downregulated proteins, were identified by electrospray ionization–mass spectrometry–mass spectrometry (ESI-MS/MS). Among these, the identities of cystatin C, Rho guanine nucleotide dissociation inhibitor, gelsolin, DEK protein, Raf kinase inhibitory protein, triose phosphate isomerase, heptaglobin-related protein, inter-alpha-trypsin inhibitor heavy chain H2, and electron transfer flavoprotein subunit beta were confirmed by Western blot analysis. These proteins were found to be involved in apoptosis, signaling, tumor progression, energy metabolism, and cell structure and motility. Therefore, these proteins have potential to be employed as biomarkers of BBP exposure and may be useful in understanding mechanisms underlying the adverse effects of BBP.

Butyl benzyl phthalate suppresses the ATP-induced cell proliferation in human osteosarcoma HOS cells

Butyl benzyl phthalate (BBP), an endocrine disruptor present in the environment, exerts its genomic effects via intracellular steroid receptors and elicits non-genomic effects by interfering with membrane ion-channel receptors. We previously found that BBP blocks the calcium signaling coupled with P2X receptors in PC12 cells (Liu & Chen, 2006). Osteoblast P2X receptors were recently reported to play a role in cell proliferation and bone remodeling. In this present study, the effects of BBP on ATP-induced responses were investigated in human osteosarcoma HOS cells. These receptors mRNA had been detected, named P2X4, P2X7, P2Y2, P2Y4, P2Y5, P2Y9, and P2Y11, in human osteosarcoma HOS cells by RT-PCR. The enhancement of cell proliferation and the decrease of cytoviability had both been shown to be coupled to stimulation via different concentrations of ATP. BBP suppressed the ATP-induced calcium influx (mainly coupled with P2X) and cell proliferation but not the ATP-induced intracellular calcium release (mainly coupled with P2Y) and cytotoxicity in human osteosarcoma HOS cells. Suramin, a common P2 receptor's antagonist, blocked the ATP-induced calcium signaling, cell proliferation, and cytotoxicity. We suggest that P2X is mainly responsible for cell proliferation, and P2Y might be partially responsible for the observed cytotoxicity. BBP suppressed the calcium signaling coupled with P2X, suppressing cell proliferation. Since the importance of P2X receptors during bone metastasis has recently become apparent, the possible toxic risk of environmental BBP during bone remodeling is a public problem of concern.

Evaluation of estrogenic activity of phthalate esters by gene expression profiling using a focused microarray (estrarray®)

AbstractPhthalates are used industrially as plasticizers and are known to contaminate natural environments, mostly as di‐ester or mono‐ester complexes. Because they are structurally similar to natural estrogens, they could act as endocrine disruptors. Here, we used a DNA microarray containing estrogen responsive genes (EstrArray®) to examine gene expression profiles in MCF‐7 cells treated with 10 μM butylbenzyl phthalate (BBP), dibutyl phthalate (DBP), diethyl phthalate (DEP), and diisopropyl phthalate (DIP) along with the natural estrogen 17β‐estradiol ([E2], 10 nM). The profiles for phthalate esters and E2 were examined by correlation analysis using correlation coefficients (r‐values) and cluster analysis. We found that BBP showed the highest correlation with E2 (r = 0.85), and DEP and DIP showed moderate r‐values (r = 0.52 and r = 0.49, respectively). Dibutyl phthalate exhibited the lowest (but still significant) correlation with E2 (r = 0.36). Furthermore, among the pairs of chemicals, DEP‐DIP and DIP‐DBP showed very high correlations (r = 0.90 and r = 0.80, respectively), and the other pairs showed moderate relationships, which reflected how structurally close they are to each other. The analysis of six functional groups of genes (enzymes, signaling, proliferation, transcription, transport, and others) indicated that the genes belonging to the enzyme, transcription, and other functional groups showed common responses to phthalate esters and E2. Although the effect of BBP was similar to that of E2, the other phthalate esters showed different types of effects. These results indicate that the structure of estrogenic chemicals is strongly related to their estrogenic activity and can be evaluated by appropriate grouping of the responsive genes by focused microarray analysis.

Effects of butyl benzyl phthalate on neurobehavioral development of rats

To study the effects of butyl benzyl phthalate on neurobehavioral development of rats. Levels of 0 (control), 0.05%, 0.25%, and 0.75% butyl benzyl phthalate (BBP) was given in the diet from 4 weeks of age of female F0 generation to 6 weeks of age of F1 generation in Wistar rats, including the period of the female F0 generation's mating, gestation and lactation and the F1 generation's growth and development. Selected parameters of neurobehavioral development were observed in F1 generation. (1)For the male F(1) generation, surface righting at postnatal (PND) 4 th day was significantly delayed in the low-dose group (P < 0.05) (scoring: 56 vs 61), cliff avoidance at PND 7 was significantly depressed in the high-dose group (P < 0.05) (scoring: 41), air righting at PND 14 was significantly depressed in all treatment groups (P < 0.05). In open field test, low- and high-dose groups moved more than control group (P < 0.05). In Morris water maze test, the escape latency was significantly delayed in the low-dose group at the 5th day of the 5 days' place navigation task (P < 0.05). (2) For the female F1 generation, there were no differences among groups in any parameter in the experiment (P > 0.05). BBP may affect the neurobehavioral development only in male rats in the F1 generation.

Effect of Butyl Benzyl Phthalate on Early Postnatal Mortality in Rats

ABSTRACTThe present study was undertaken to examine early postnatal mortality in rat pups following exposure to butyl benzyl phthalate (BBP) during pregnancy. Seventeen pregnant rats were given 750 mg/kg bw/day of BBP by oral gavage on gestation days 13, 14, and 15, and the volume of each dose was adjusted to 5 ml/kg body weight. Four rats were given olive oil only and served as control. Natural birth was allowed to take place. One hundred and eighty-three pups were born to the experimental rats and 46 pups to the control group. Close observation of the newborn pups during the first 3 h of life revealed that all the pups in both the control and experimental groups were born alive. Only six pups from the experimental group (3.2%) died within this time period. These and four control pups were fixed and decalcified. Histological examination of the thoracic cavity of the newborn rats in both groups revealed no differences in the position or size of any of the heart chambers, ductus arteriosus, or great vessels. However, the lungs of the six experimental pups that died showed athelectasia and bronchi dilatation. The results therefore suggest that exposure to BBP of rats during pregnancy does not produce significant postnatal mortality in their offspring.