Histopathological effects of 4-tert-octylphenol treatment through the pregnancy period, on the pituitary, adrenal, pancreas, thyroid and parathyroid glands of offspring rats at adulthood

Investigation of combined effects of propyl paraben and methyl paraben on the hypothalamic-pituitary-adrenal axis in male rats

The aim of this study was to investigate the endocrine-disrupting effects of methyl paraben (MeP) and propyl paraben (PrP) mixture on the hypothalamic-pituitary-adrenal axis (HPA). In this study, six experimental groups were designated. These groups included three control groups (control, corn oil control, and positive control (50 mg/kg/day BPA)) and three dose groups (10, 100, and 500 mg/kg/day MeP+PrP). MeP with PrP were mixed in a 1:1 ratio and administered to the 42-day-old male rats by oral gavage for 30 days. At the end of the experiment, adrenocorticotropic hormone (ACTH), corticosterone and aldosterone hormones were analyzed in serum. Effects of MeP+PrP on the adrenal glands were investigated by immunohistochemical staining of 11ß hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) enzymes involved in the synthesis steps of corticosterone and aldosterone. Also, pituitary and adrenal glands were examined histopathologically. In the histopathological findings, cortical nodule, congestion, and edema were found in the tissues. In the pituitary gland, cytokeratin rings were detected in all MeP+PrP dose groups, supporting the increase of corticosterone and ACTH. Serum corticosterone, aldosterone, and ACTH hormone levels were increased in the 100 mg/kg/day MeP+PrP and BPA groups. Results obtained from immunohistochemical staining showed that increased staining parallelled increased corticosterone and aldosterone hormone levels. In summary, the results showed that exposure to the MeP+PrP mixture caused a significant increase in ACTH and corticosterone. Also, the MeP+PrP mixture caused a significant increase of CYP11B1 and CYP11B2. MeP+PrP exposure disrupts the normal HPA axis.

mRNA expression and protein-protein interaction (PPI) network analysis of adrenal steroidogenesis in response to exposure to phthalates in rats

Phthalate esters such as di-butyl phthalate (DBP) and di-ethyl hexyl phthalate (DEHP) used in personal care and consumer products and medical devices have potential to affect human health. We studied the effect of DBP and DEHP on critical enzymes of glucocorticoid biosynthesis pathway in the adrenal gland and pro-inflammatory cytokines in the serum in male Wistar rats. DEHP and DBP treatment altered the mRNA expression of enzymes of glucocorticoid biosynthesis pathway accompanied by a reduction in glucocorticoid production and elevation in the level of glucocorticoid regulated pro-inflammatory cytokines indicating a cascading effect of phthalates. The analysis of PPI (protein - protein interaction) network involving Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) of enzymes through STRING database revealed that all the proteins have the maximum level of interaction with the selected number of proteins. The STRING database analysis together with in vivo data indicates the potential effects of phthalates on various targets of steroidogenesis pathway with a global biological impact.

Toxicological effects of di-(2-ethylhexyl) phthalate in Gammarus pulex: a biochemical and histopathological assessment

This study aimed to reveal the toxic characteristics of di-(2-ethylhexyl) phthalate (DEHP) by examining the biochemical and histopathological changes in Gammarus pulex, exposed to different doses of DEHP. For this purpose, the lethal concentration 50 (LC₅₀) value of the DEHP was determined by using a static test and found to be 0.079 ± 0.01 ppm. Three subletal doses of DEHP were applied to the G. pulex for 24 and 96 h. Superoxide dismutase (SOD), catalase (CAT), cytochrome P450 1A1 (CYP1A1), and glutathione S-transferase (GST) activities were measured using commercial ELISA kits. The caspase method, which is an immunohistochemical analysis method, was used to determine the apoptosis that occurred in the G. pulex. The results showed that the CYP1A1 activities decreased in the groups exposed to different doses of DEHP compared to the control group (p > 0.05). CAT activity was found to increase in the application groups at the 24 and 96 h compared to the control group. In addition, it was found that SOD and GST activities increased at the 96 h compared to the control group. In light of the microscope examination of the model organism, hemolymphatic lacunae filled with hemolymph and reduction or absence of hemolymphatic ducts were observed especially in the G. pulex gills. Collapse of the gills and hyperplasia were observed after 96 h. As a result, it is suggested that changes in SOD, CAT, and GST activities can potentially be used as sensitive biomarkers for risk assessment in the environment and increased immunoreactivity in G. pulex caused by DEHP depending on increased application doses and application times.

OctylPhenol (OP) Alone and in Combination with NonylPhenol (NP) Alters the Structure and the Function of Thyroid Gland of the Lizard Podarcis siculus

Different environmental contaminants disturb the thyroid system at many levels. AlkylPhenols (APs), by-products of microbial degradation of AlkylPhenol Polyethoxylates (APEOs), constitute an important class of Endocrine Disrupting Chemicals (EDCs), the two most often used environmental APs being 4-nonylphenol (4-NP) and 4-tert-octylphenol (4-t-OP). The purpose of the present study was to investigate the effects on the thyroid gland of the bioindicator Podarcis siculus of OP alone and in combination with NP. We used radioimmunoassay to determine their effects on plasma 3,3',5-triiodo-L-thyronine (T₃), 3,3',5,5'-L-thyroxine (T₄), thyroid-stimulating hormone (TSH), and thyrotropin-releasing hormone (TRH) levels in adult male lizards. We also investigated the impacts of AP treatments on hepatic 5'ORD (type II) deiodinase and hepatic content of T₃ and T₄. After OP and OP + NP administration, TRH levels increased, whereas TSH, T₃, and T₄ levels decreased. Lizards treated with OP and OP + NP had a higher concentration of T₃ in the liver and 5'ORD (type II) activity, whereas T₄ concentrations were lower than that observed in the control group. Moreover, histological examination showed that the volume of the thyroid follicles became smaller in treated lizards suggesting that that thyroid follicular epithelial cells were not functionally active following treatment. This data collectively suggest a severe interference with hypothalamus-pituitary-thyroid axis and a systemic imbalance of thyroid hormones.

Influence of in utero di-n-hexyl phthalate and di-cyclohexyl phthalate exposure on the endocrine glands and T3, T4, and TSH hormone levels of male and female rats: Postnatal outcomes

The present study was designed to evaluate the effects of di-n-hexyl phthalate (DHP) and di-cyclohexyl phthalate (DCHP) on endocrine organs in rats. Oil control, 20-, 100-, and 500 mg/kg dose groups were selected and administered to pregnant rats on gestational days 6-19 by oral gavage. The neonatal stages of rats continued until postnatal day 20 and the- juvenile stages of rats continued until postnatal day of 32. The rats were allowed to mature until the neonatal and juvenile stages and there after, they were divided into four groups corresponding to the treatment levels. Body and organ weights were recorded, serum was collected, and thyroid, pancreas, pituitary gland, and adrenal gland were removed. There was a decrease in body weights in the 20- and 500mg/kg DHP and in the 20-mg/kg DCHP dose groups in neonatal male rats. In contrast, for female rats, there was an increase in body weights in the 100-mg/kg DCHP dose group and there was a decrease in body weights in the 500-mg/kg DHP dose group. Body weights were increased at 20 and 500 mg/kg in the DHP-exposed juvenile male rats. Serum thyroid-stimulating hormone (TSH) levels were increased in neonatal male rats, while they were increased in the 100-mg/kg DHP group of neonatal and juvenile female rats. Serum triiodothyronine (T3) levels were increased at the high dose of DHP for neonatal male rats and at the low and high dose levels of DCHP for female rats. Serum thyroxine (T4) levels were increased in neonatal rats for DHP. Also, some histopathological changes were observed in the thyroid, pancreas, adrenal, and pituitary gland. In conclusion, it was shown that DHP and DCHP caused negative effects on T3, T4, and TSH hormone levels.

Birth outcome measures and prenatal exposure to 4-tert-octylphenol

Exposure to 4-tert-octylphenol (tOP) has been linked with adverse health outcomes in animals and humans, while epidemiological studies about associations between prenatal exposure to tOP and fetal growth are extremely limited. We measured urinary tOP concentrations in 1100 pregnant women before their delivery, and examined whether tOP levels were associated with birth outcomes, including weight, length, head circumference and ponderal index at birth. tOP could be detected in all samples, and the median uncorrected and creatinine-corrected tOP concentrations were 0.90 μg/L (range from 0.25 to 20.05 μg/L) and 1.33 μg/g creatinine (range from 0.15 to 42.49 μg/g creatinine), respectively. Maternal urinary log-transformed tOP concentrations were significantly negatively associated with adjusted birth weight [β (g) = -126; 95% confidence interval (CI): -197, -55], birth length [β (cm) = -0.53; 95% CI:-0.93, -0.14], and head circumference [β (cm) = -0.30; 95% CI: -0.54, -0.07], respectively. Additionally, considering sex difference, these significant negative associations were also found among male neonates, while only higher maternal tOP concentrations were associated with a significant decrease in birth weight among female neonates. This study suggested significant negative associations between maternal urinary tOP concentrations and neonatal sizes at birth, and they differed by neonatal sex. Further epidemiological studies are required to more fully elaborate the associations between prenatal tOP exposure and birth outcomes.

Hepatic and renal functions in growing male rats after bisphenol A and octylphenol exposure

This study aimed to determine the effects of 13-week bisphenol A (BPA) and octylphenol (OP) exposure on the liver, kidney, and spleen of growing male rats. A total of 29 male Wistar rats aged 4–5 weeks were divided into five groups. The treatment groups were given low-dose (125 mg/kg bw/day) or high-dose (250 mg/kg bw/day) BPA or OP. These compounds were dissolved in corn oil and given via oral route for 13 weeks. Rats in the control group received corn oil for 13 weeks, as well. After 13 weeks of treatment, blood samples were analyzed for biochemical parameters. Tissue samples from the liver, kidney, and spleen were histopathologically and histomorphometrically examined. Liver tissue specimens were also stained by immunohistochemically; the number of apoptotic cells was counted, and the apoptotic indices were calculated. There were significant differences between the control and treatment groups with respect to the following parameters: body weight, relative left kidney weight, and total protein, glucose, and alkaline phosphatase levels. Edema and parenchymal degeneration in the liver and tubular degeneration in the kidney were more frequent in the treatment groups. The control and treatment groups were comparable with respect to the frequency of histopathological lesions in the spleen. Glomerular histomorphometry revealed no significant differences between the control and treatment groups. No significant differences existed between the control and treatment groups with respect to the number of apoptotic cells and apoptotic indices. Subchronic exposure to BPA and OP induced functional and structural changes in the liver, kidney, and spleen of growing male rats.

Oxidative stress induced by thyroid dysfunction in rat erythrocytes and heart

The aim of this study was to determine whether the effects of thyroid dysfunction induce oxidative stress in the blood and heart of male Wistar rats. Rats were randomly divided into three groups: group I served as control rats. Group II was treated daily with 0.05% benzythiouracile (BTU) administered in drinking water. Rats of group III have received l-thyroxine sodium salt (0.0012%), in drinking water. The results showed that thyroid dysfunction rats had poor growth performance. On the other hand, in hyperthyroid rats, a marked decrease compared with control occurred of some hematological parameters such red blood cell number (RBC), haemoglobin (Hb) concentration and haematocrit (Ht). There was also a significant increase in erythrocyte numbers and heart TBARS concentrations in hypothyroid rats compared with control. These results were associated with a fall in the total antioxidant status (TAS) in the serum of the hyperthyroid rats. Alteration of the antioxidant system in the hypo-/hyperthyroidism-induced rats was confirmed by the significant increase of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities and a decline in glutathione (GSH) content in both tissues were detected in hyperthyroid group compared to controls. On the other hand, serum transaminase activities (aspartate transaminase (AST); alanine transaminase (ALT)) were elevated indicating hepatic cellular damage after treatment with exogenous L-thyroxine. Moreover, serum lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT) and creatine phosphokinase (CPK) activities were increased in the hyperthyroidism rats. These results indicated that excessive thyroxin (long term) ingestion had an adverse effect on animal health and performance. We conclude that thyroid dysfunction induces oxidative stress and modifies some biochemical parameters of erythrocytes, heart and liver disease; our results show the occurrence of a state of oxidizing stress in relation to hyperthyroidism.