Acrylamide alters glycogen content and enzyme activities in the liver of juvenile rat.

Acrylamide (AA) is spontaneously formed in carbohydrate-rich food during high-temperature processing. It is neurotoxic and potentially cancer causing chemical. Its harmful effects on the liver, especially in a young organism, are still to be elucidated. The study aimed to examine main liver histology, its glycogen content and enzyme activities in juvenile rats treated with 25 or 50mg/kg bw of AA for 3 weeks. Liver samples were fixed in formalin, routinely processed for paraffin embedding, sectioning and histochemical staining. Examination of haematoxylin and eosin (H&E)-stained sections showed an increase in the volume of hepatocytes, their nuclei and cytoplasm in both AA-treated groups compared to the control. In Periodic acid-Schiff (PAS)-stained sections in low-dose group was noticed glycogen reduction, while in high-dose group was present its accumulation compared to the control, respectively. Serum analysis showed increased activity of aspartate aminotransferase (AST), and decreased activity of alanine aminotransferase (ALT) in both AA-treated groups, while the activity of alkaline phosphatase (ALP) was increased in low-dose, but decreased in high-dose group compared to the control, respectively. Present results suggest a prominent hepatotoxic potential of AA which might alter the microstructural features and functional status in hepatocytes of immature liver.

Atrazine-induced changes in the myocardial structure of peripubertal rats.

The aim of the present study was to investigate the effect of atrazine (6-chloro-N(2)-ethyl-N(4)-isopropyl-1,3,5-triazine-2,4-diamine) on the left ventricle myocardium in juvenile/peripubertal male Wistar rats. Atrazine was administered orally at 50 or 200 mg/kg of body weight dose for 28 consecutive days. In order to assess possible structural alterations, tissue sections were examined histologically and then subjected to quantification analysis using stereological methods. The tissue specimens were routinely processed and stained with Mallory trichrome method in order to clearly distinguish muscle cells from the connective tissue components. A toluidine blue staining method was additionally used for the demonstration of mast cells. Statistically significant increase in length density and numerical density of capillaries were found at both the investigated doses of atrazine compared with the control. The increase in surface density and volume density of capillaries found at lower dosage of atrazine was significant in comparison with the control. The extensive mast cell degranulation was noted on the histological examination at both doses of the applied chemical. No significant changes were demonstrated for the stereological parameters of cardiomyocytes. Based on the available published data and the present results, it can be concluded that atrazine promoted angiogenesis in the rat myocardium, which might be partially mediated by mast cells.

Alterations in jejunal morphology and serotonin-containing enteroendocrine cells in peripubertal male rats associated with subchronic atrazine exposure.

The effect of atrazine on jejunum was investigated by histopathological examination and quantification analysis related to the morphological parameters of the jejunum. The experiment was performed on male Wistar rats from postnatal day 23-51. Atrazine was administered by gavage daily to one group of rats at 50 mg/kg of body weight (bw) dose, to the second at 200 mg/kg bw while the third group was the control. At the end of the experiments after 28 days of treatment, tissue samples were routinely processed and stained with haematoxylin eosin. Additionally, the histochemical staining with periodic acid Schiff-alcian blue was used to demonstrate goblet cells and the immunohistochemistry protocol for serotonin-containing enteroendocrine cells. A significant decrease in the height of epithelial cells covering the intestinal villi, the villus height to total mucosa thickness ratio and the villus height to crypt depth ratio was found at both doses of atrazine. The crypt depth, total mucosa thickness and the thickness of tunica muscularis were significantly increased by the high dose of atrazine only. The number of serotonin-positive endocrine cells significantly decreased in rats treated with the low dose of atrazine. Overall, these results suggest the alterations in intestinal absorption and support the role of atrazine as an endocrine-disrupting compound.

Studies on the synergistic effects of extremely low-frequency magnetic fields and the endocrine-disrupting compound atrazine on the thyroid gland.

PURPOSE: The aim of this study was to examine the effect of extremely low-frequency magnetic fields (MF) and the endocrine-disrupting compound atrazine, each separately, on the thyroid gland of juvenile-peripubertal rats, and to investigate the possible synergistic effect of these two factors combined. MATERIALS AND METHODS: The study was performed on male Wistar rats from postnatal day 23-53. Animals were divided into six groups: (1) 4 h/day exposure to MF (50 Hz, 100-300 µT, 54-160 V/m), (2) 20 mg/kg of body weight (bw) of atrazine, (3) 200 mg/kg bw of atrazine, (4) MF with 20 mg/kg bw of atrazine (5) MF with 200 mg/kg bw of atrazine, and (6) control. RESULTS: Light and electron microscopic studies demonstrated no significant alterations in the thyroid structure between the treated groups and the control. Significant outcomes were found regarding the volume density of thyroid follicles and the connective tissue between the MF-exposed group when compared to both atrazine treatments and the combined treatments. The high dose of atrazine significantly affected the number of mast cells compared to the control. CONCLUSIONS: No synergistic effect of the MF and the endocrine-disrupting compound atrazine on the thyroid gland has been found. The specific histological alterations of the thyroid parenchyma observed in some treated groups require further investigation.

Combined exposure of peripubertal male rats to the endocrine-disrupting compound atrazine and power-frequency electromagnetic fields causes degranulation of cutaneous mast cells: a new toxic environmental hazard?

The effects of single and combined treatments of the endocrine-disrupting compound atrazine and the power-frequency electromagnetic fields (EMFs) were investigated on cutaneous mast cells in juvenile/peripubertal male Wistar rats. Animals were divided into six groups: (1) 4 h/day exposure to EMFs (50 Hz), (2) 20 mg/kg of body weight (bw) of atrazine, (3) 200 mg/kg bw of atrazine, (4) EMFs with 20 mg/kg bw of atrazine, (5) EMFs with 200 mg/kg bw of atrazine, and (6) control. Both the atrazine and the combined treatments, but not the single EMF exposure, increased the number of degranulated mast cells. Statistically significant differences were demonstrated between the control and both of the combined treatments (p<0.01 and p<0.001, respectively). Additionally, low and high doses of atrazine combined with the EMFs were found significantly different when compared to the EMF group alone (both at p<0.001). Considering the biological importance of mast cells in cutaneous immune reactions, future studies should reveal whether combined exposures to chemical and physical environmental agents pose a serious health risk.

Photoperiodism as a modifier of effect of extremely low-frequency electromagnetic field on morphological properties of pineal gland.

The aim of our study was to determine, using histological and stereological methods, whether photoperiodism has any impact on the effects that chronic (three-month long) exposure to LF-EMF (50Hz) has on morphological characteristics on rat's pineal gland. The experiment was performed on 48 Mill Hill male rats (24 experimental and 24 control). Upon birth, 24 rats were exposed for 7h a day, 5 days a week for 3 months to LF-EMF (50 Hz, 50-500microT, 10V/m). In the winter (short days, long nights), the activity of the pineal gland and neuroendocrine sensitivity is increased. The study was performed both during summer and winter, following the identical protocol. After sacrifice of animals, samples of pineal gland were processed for HE staining and then were analyzed using the methods of stereology. The most significant changes in epiphysis in the first group of animals in wintertime are: altered glandular feature, hyperemia, reduced pinealocytes with pale pink, poor cytoplasm and irregular, stick-form nuclei. In the second group (II) pinealocytes are enlarged, with vacuolated cytoplasm and hyper chromatic, enlarged nucleus. Morphological changes of pineal gland at rats in the summertime were not as intense as in the winter and finding of the gland in the group II is compatible with those from the control group. Stereological results show both in winter and summer in the first group the decrease of volume density of pinealocytes, their cytoplasm and nuclei and in the second group in winter increase the volume density of pinealocytes, cytoplasm and nuclei, while in the second group the results in summertime are equal to those from the control group. Photoperiodism is modifier of effect of LF-EMF on morphological structure of pineal gland, because the gland recovery is incomplete in winter and reversible in summer.

Light and electron microscopic study of the thyroid gland in rats exposed to power-frequency electromagnetic fields.

The effect of 50 Hz electromagnetic field (EMF) on thyroid gland was studied using light and transmission electron microscopes. Two-month-old male rats were exposed to an EMF (100-300 microT, 54-160 V m(-1)) for 4 h a day, 5 days a week for 1 month. A predominance of microfollicles with less colloid content and dilated blood capillaries was found in the EMF group. Stereological counting showed a statistically significant increase of the volume density of follicular epithelium, interfollicular tissue and blood capillaries as well as the thyroid activation index, as compared to the controls. The volume density of colloid significantly decreased. Ultrastructural analysis of thyroid follicular cells in the EMF group revealed the frequent finding of several colloid droplets within the same thyrocyte with the occasional presence of large-diameter droplets. Alterations in lysosomes, granular endoplasmic reticulum and cell nuclei compared to the control group were also observed. Taken together, the results of this study show the stimulative effect of power-frequency EMF on thyroid gland at both the light microscope and the ultrastructural level.

Histological characteristics of cutaneous and thyroid mast cell populations in male rats exposed to power-frequency electromagnetic fields.

PURPOSE: The objective of this study was to determine whether mast cells (MC) in skin and thyroid gland, cutaneous nerve fibers and eosinophils are sensitive to the influence of electromagnetic fields (EMF). MATERIALS AND METHODS: The experiment was performed on two-month-old Wistar male rats, exposed to 50 Hz EMF (100-300 microT, 54-160 V/m) for 4 h a day, seven days a week during one month. After sacrifice, samples of skin and thyroid were processed for toluidine blue staining or indirect immunohistochemistry. The M42 grid placed in the ocular of a light microscope and a special microscopic frame placed in the ocular of a fluorescence microscope were used for stereological analysis. RESULTS: The numerical and volume density of intact type A MC in the thyroid of the exposed group was significantly higher compared to the control. A number of MC and immunoreactive nerve fibers were observed in the skin and of histamine-immunoreactive MC in the thyroid of exposed animals. The differences in stereological data were not statistically significant by the Mann-Whitney test. CONCLUSIONS: The results indicate certain alterations of cutaneous and thyroid MC in rats exposed to EMF. However, the possible outcome of changes in the MC population under EMF influence on morphophysiological properties of other structures in skin and thyroid requires further investigation.

The effect of extremely low-frequency electromagnetic fields on skin and thyroid amine- and peptide-containing cells in rats: an immunohistochemical and morphometrical study.

The aim of this study was to investigate the influence of extremely low-frequency electromagnetic fields (ELF-EMFs) on mast cells (MCs), parafollicular cells, and nerve fibers in rat skin and thyroid gland. The experiment was performed on 24 2-month-old Wistar male rats exposed for 4h a day, 7 days a week for 1 month to EMFs (50 Hz, 100-300 microT, 54-160 V/m). After sacrifice, samples of skin and thyroid were processed for indirect immunohistochemistry or toluidine blue staining and then were analyzed using the methods of stereology. The antibody markers to serotonin, substance P, calcitonin gene-related peptide (CGRP), and protein gene product 9.5 (PGP) were applied to skin sections and PGP, CGRP, and neuropeptide Y (NPY) markers to the thyroid. A significantly increased number of serotonin-positive MCs in the skin and NPY-containing nerve fibers in the thyroid of rats exposed to ELF-EMF was found compared to controls, indicating a possible EMF effect on skin and thyroid vasculature.

Stereological analysis of thyroid mast cells in rats after exposure to extremely low frequency electromagnetic field and the following "off" field period.

Influence of extremely low frequency electromagnetic field (ELF-EMF) on thyroid gland mast cells was investigated on male Mill Hill rats. Animals were exposed to EMF (50 Hz, 50 microT to 500 microT, 10 V/m) from 24 hours after birth, 7 hours/day, 5 days/week for three months when a part of animals (group I) was sacrificed, while the rest of them were subjected to recovery evaluation and sacrificed after one (group II), two (group II) and three (group IV) weeks following the exposure. Stereological analysis on toluidine blue-stained paraffin sections showed increased volume density of degranulated mast cells in all groups and, except in group III, and numerical density as well, implicating the sensitivity of thyroidal mast cells to power frequency EMFs. Since in our previous investigations, morphofunctional alterations of thyroid gland in rats exposed to ELF-EMF were found the contribution of released mast cell mediators to these changes could be presumed.