THE EFFECTS OF ENDOCRINE DISRUPTORS ON FEMALE GONADAL AXIS: AN UPDATE.

Endocrine disruptors (EDs) are considered to have an impact on the function of reproductive axis at different levels as well on reproductive organs in both sexes. Complexity of female reproductive system influenced with various stressors including EDs lead to morphological and functional alterations. This is resulting in modulation of neuroendocrine regulation with consequent developmental irregularities and derangements, causative infertility, endometriosis as well as premature ovarian insufficiency or polycystic ovary syndrome. A number of experimental clues was obtained on female animal models using various EDs such as synthetic estrogens and phytoestrogens, neurotransmitters, pesticides or various chemicals. These substances lead towards consequent derangement of the neuroendocrine control of reproduction from early phases of reproductive development towards different phases of adult reproductive period. This text will address some novel insights into the effects of EDs on neuroendocrine regulation of gonadal axis, effects on ovaries as well on endometrium during implantation period.

The correlation of SYNTAX score by coronary angiography with breast arterial calcification by digital mammography.

AIM: To evaluate the hypothesis that breast arterial calcification (BAC) may predict coronary artery disease (CAD) severity. MATERIALS AND METHODS: The study comprised 102 women >45 years (mean age 62±8 years) referred for digital mammography after coronary angiography. BAC was assessed using the Likert scale and CAD severity was assessed using the SYNTAX (SYNergy between percutaneous coronary intervention with TAXus and cardiac surgery trial) score. RESULTS: In comparison to the low SYNTAX score group (≤22) patients with a intermediate-to-high SYNTAX score (>22) were older (p=0.001), they more often had hypercholesterolaemia (p<0.001), diabetes (p=0.021), and a history of smoking (p=0.048). They also had a statistically higher level of fasting blood glucose (p<0.001), glycated haemoglobin (HbA1C; p<0.001), triglycerides (p=0.002), fibrinogen (p=0.001), whereas high-density lipoprotein (HDLc) was lower than in the group with a SYNTAX score ≤22 (p=0.005). BAC was significantly higher in patients with a SYNTAX score >22 (p<0.001). At multivariate analysis, BAC (odds ratio [OR] 34.24, 95% confidence interval [CI]: 8.05-145.7, p<0.001), hypercholesterolaemia (OR 22.65, 95% CI: 4.18-122.81, p<0.001) and fibrinogen (OR 2.55, 95% CI: 1.28-5.07, p=0.008) were independent predictive factors for patients with intermediate-to-high SYNTAX score. CONCLUSIONS: In women >45 years, there was a significant correlation between the severity of CAD as evaluated by the SYNTAX score and BAC as evaluated by the Likert scale. BAC, hypercholesterolaemia, and fibrinogen may be used as an additional diagnostic tool to predict the presence and severity of CAD.

The effect of subchronic supplementation with folic acid and l-arginine on homocysteine-induced seizures.

The aim of the present study was to examine the effect of subchronic co-administration of folic acid (F) and l-arginine (A) on behavioural and electroencephalographic (EEG) characteristics of dl homocysteine thiolactone (H) induced seizures in adult rats. The activity of membrane ATPases in different brain regions were also investigated. Rats were treated with F, A, or vehicle for 15 days (regimen: F 5 mg/kg + A 500 mg/kg (F5A500); F 10 mg/kg + A 300 mg/kg (F10A300)). Seizures were elicited by convulsive dose of H (H, F5A500H, F10A300H) Subchronic supplementation with F and A did not affect seizure incidence, number of seizure episodes, and severity in F5A500H and F10A300H groups vs. H group. However, a tendency to increase latency and decrease the number of seizure episodes was noticed in the F10A300H group. EEG mean spectral power densities during ictal periods were significantly lower in F10A300H vs. H group. The activity of Na+/K+-ATPase and Mg2+-ATPase was significantly increased in almost all examined structures in rats treated with F and A. We can conclude that subchronic supplementation with folic acid and l-arginine has an antiepileptic effect in dl homocysteine thiolactone induced epilepsy.

Exercise decreases susceptibility to homocysteine seizures: the role of oxidative stress.

The aim of the study was to examine the effects of chronic exercise training on seizures induced by homocysteine thiolactone (HCT) in adult rats. Rats were assigned to: sedentary control; exercise control; sedentary+HCT; exercise+HCT group. Animals in the exercise groups ran 30 min daily on a treadmill for 30 consecutive days (belt speed 20 m/min), while sedentary rats spent the same time on the treadmill (speed 0 m/min). On the 31st day, the HCT groups received HCT (8.0 mmol/kg), while the control groups received vehicle. Afterwards, convulsive behavior and EEG activity were registered. Lipid peroxidation, superoxide dismutase (SOD) and catalase (CAT) activity were ascertained in the rat hippocampus. No signs of seizures were registered in sedentary and exercise control rats. Seizure latency was increased, while number of seizure episodes and spike-and-wave discharges (SWD) in EEG were decreased in the exercise+HCT compared to the sedentary+HCT group. Seizure incidence, the severity thereof and duration of SWDs were not significantly different between these groups. Exercise partly prevented increase of lipid peroxidation and decrease of the SOD and CAT activity after HCT administration. These results indicate beneficial effects of exercise in model of HCT-induced seizures in rats, what could be, at least in part, a consequence of improved antioxidant enzymes activity.

The correlation between lipid peroxidation in different brain regions and the severity of lindane-induced seizures in rats.

The aim of this study was to investigate the dynamics of lipid peroxidation and the possible correlation between lipid peroxidation in different brain regions and behavioral manifestations in lindane-induced seizures in rats. Male Wistar rats were divided into the following groups: 1. control, saline-treated group; 2. dimethylsulfoxide (DMSO)-treated group; 3. lindane-treated group (8 mg/kg), intraperitoneally. Animals were sacrificed 0.5 or 4 h after treatment and the malondialdehyde level and superoxide dismutase (SOD) activity were determined in various brain regions spectrophotometrically. Behavioral changes were classified according to the descriptive scale (0--no response, 1--head nodding, lower jaw twitching; 2--myoclonic body jerks, bilateral forelimb clonus with full rearing; 3--progression to generalized clonic convulsions followed by tonic extension of fore- and hind limbs and tail; 4--status epilepticus). A significant rise in the malondialdehyde level was detected in the cerebral cortex, hippocampus, and thalamus of lindane-treated animals 0.5 and 4 h after administration (P < 0.05). SOD activity (total and mitochondrial) was significantly decreased in the hippocampus and the cortex of lindane-treated animals at both time points (P < 0.05). An initial fall in SOD activity was detected in the thalamus 4 h after lindane administration (P < 0.05). A positive correlation between seizure severity and the malondialdehyde level was found in the hippocampus at both time points (P < 0.01). These results suggest that lipid peroxidation may contribute to the neurotoxic effects of lindane in early acute lindane intoxication and that behavioral manifestations correlate with lipid peroxidation in the hippocampus of lindane-treated rats.

Effect of acute lindane and alcohol intoxication on serum concentration of enzymes and fatty acids in rats.

This study examines possible synergistic effects of lindane and ethanol on inducing liver injury and serum fatty acid derangement in adult male Wistar rats. When administered together, ethanol and lindane-induced even more pronounced increase of alanine aminotransferase (165 +/- 10 U/L) and gamma-glutamyltranspeptidase activity (10.3 +/- 0.6 U/L) than after isolated administration of either substance. In addition, separate administration of lindane and ethanol was followed by a significant decrease of linoleic acid level in the serum (301 +/- 38 mg/L, 276 +/- 35 mg/L vs. 416 +/- 48 mg/L). However, when ethanol administration was followed by lindane injection, serum linoleic acid was at the similar level found in the control group (516 +/- 62 mg/L). Ethanol-treated rats that received lindane 30 min after ethanol administration have shown a marked increase of palmitic (421 +/- 27 mg/L) and linolic acid level (43 +/- 5 mg/L) in comparison with rats that have been treated only with ethanol (316+/-26 mg/L for palmitic and 32 +/- 2 mg/L for linolic acid) or lindane (295 +/- 26 mg/L for palmitic and 301 +/- 38 mg/L for linolic acid). Linolic acid level was significantly greater in comparison with control group (29 +/- 1 mg/L). In conclusion, this study found enough evidence to support the hypothesis that acute ethanol intoxication potentiates lindane-induced liver injury and enhances lipid derangement.

The Influence of Finasteride on Mean and Relative Spectral Density of EEG Bands in Rat Model of Thioacetamide-Induced Hepatic Encephalopathy.

Liver failure is associated with a neuropsychiatric syndrome, known as hepatic encephalopathy (HE). Finasteride, inhibitor of neurosteroid synthesis, may improve the course of HE. The aim of our study was to investigate the influence of finasteride on mean and relative power density of EEG bands, determined by spectral analysis, in rat model of thioacetamide-induced HE. Male Wistar rats were divided into groups: (1) control; (2) thioacetamide-treated group, TAA (900 mg/kg); (3) finasteride-treated group, FIN (150 mg/kg); and (4) group treated with finasteride (150 mg/kg) and thioacetamide (900 mg/kg), FIN + TAA. Daily doses of FIN (50 mg/kg) and TAA (300 mg/kg) were administered during 3 subsequent days, and in FIN + TAA group FIN was administered 2 h before every dose of TAA. EEG was recorded 22-24 h after treatment and analyzed by fast Fourier transformation. While TAA did not induce significant changes in the beta band, mean and relative power in this band were significantly higher in FIN + TAA versus control group (p < 0.01). TAA caused a significant decline in mean power in alpha, theta, and delta band, and in FIN + TAA group the mean power in these bands was significantly higher compared with control. While in TAA group relative power was significantly decreased in theta (p < 0.01) and increased in delta band (p < 0.01) versus control, the opposite changes were found in FIN + TAA group: an increase in theta (p < 0.01) and a decrease in delta relative power (p < 0.01). In this study, finasteride pretreatment caused EEG changes that correspond to mild TAA-induced HE.

The effect of subchronic supplementation with folic acid on homocysteine induced seizures.

Influence of folic acid on the CNS is still unclear. Folate has a neuroprotective effect, while on the other hand excess folate can exacerbate seizures in epileptics. The aim of the present study was to examine the effect of subchronic administration of folic acid on behavioural and electroencephalographic (EEG) characteristics of DL homocysteine thiolactone induced seizures in adult rats. The activity of Na⁺/K⁺-ATPase and Mg²âº-ATPase in different brain regions was investigated. Adult male Wistar rats were divided into groups: 1. Controls (C, 0.9% NaCl); 2. DL homocysteine-thiolactone 8.0 mmol/kg (H); 3. Subchronic supplementation with folic acid 5 mg/kg for 7 days (F) and 4. Subchronic supplementation with F + single dose of H (FH). Seizure behaviour was assessed by incidence, latency, number and intensity of seizure episodes. Seizure severity was described by a descriptive scale with grades 0-4. For EEG recordings, three gold-plated recording electrodes were implanted into the skull. Subchronic supplementation with folic acid did not affect seizure incidence, median number of seizure episodes and severity in FH, comparison with H (p > 0.05). The majority of seizure episodes in all groups were of grade 2. There were no significant differences in lethal outcomes at 24 h upon H injection in the FH vs. H group. The activity of Na⁺/K⁺-ATPase and Mg²âº-ATPase was significantly increased in almost all examined structures in the FH vs. H group. Subchronic folic acid administration did not exacerbate H induced seizures and completely recovered the activity of ATPases.

Homocysteine thiolactone-induced seizures in adult rats are aggravated by inhibition of inducible nitric oxide synthase.

Homocysteine and its metabolites (homocysteine thiolactone (HT)) induce seizures via different but still not well-known mechanisms. The role of nitric oxide (NO) in epileptogenesis is highly contradictory and depends on, among other factors, the source of NO production. The aim of the present study was to examine the effects of aminoguanidine, selective inhibitor of inducible NO synthase (iNOS), on HT-induced seizures. Aminoguanidine (50, 75, and 100 mg/kg, intraperitoneally (i.p.)) was injected to rats 30 min prior to inducing HT (5.5 mmol/kg, i.p.). Seizure behavior was assessed by seizure incidence, latency time to first seizure onset, number of seizure episodes, and their severity during observational period of 90 min. Number and duration of spike and wave discharges (SWDs) were determined in electroencephalogram (EEG). Seizure latency time was significantly shortened, while seizure incidence, number, and duration of HT-induced SWD in EEG significantly increased in rats receiving aminoguanidine 100 mg/kg before subconvulsive dose of HT. Aminoguanidine in a dose-dependent manner also significantly increased the number of seizure episodes induced by HT and their severity. It could be concluded that iNOS inhibitor (aminoguanidine) markedly aggravates behavioral and EEG manifestations of HT-induced seizures in rats, showing functional involvement of iNOS in homocysteine convulsive mechanisms.

Spectral analysis of thioacetamide-induced electroencephalographic changes in rats.

Thioacetamide (TAA) is widely used as a model of hepatic encephalopathy (HE). The aim of our study was to investigate the effects of TAA on electroencephalographic (EEG) changes in rats and to compare them with human HE. Male Wistar rats were divided into groups: (1) saline-treated group and (2) TAA-treated groups: TAA(300) (300 mg/kg), TAA(600) (600 mg/kg), and TAA(900) (900 mg/kg). Daily dose of TAA (300 mg/kg) was administered intraperitoneally once (TAA(300)), twice (TAA(600)), or thrice (TAA(900)) in subsequent days. EEG changes were recorded about 24 h after the last dose of TAA. Absolute and relative power density in alpha bands were significantly higher in TAA(300) versus control group. In TAA(300), absolute beta power density was higher and relative beta power density was lower versus control group. Absolute alpha, theta, delta, and relative theta power were significantly lower, while relative power in delta band was significantly higher in TAA(900) versus control group (p < 0.01). In conclusion, decrease in EEG voltage with an increase in delta relative power, which correspond to the EEG manifestations of severe HE in humans, was observed in TAA(900) group. Electrical activity in TAA(300) group correlates with mild HE in humans.

The effect of N-methyl-D-aspartate receptor antagonists on D,L-homocysteine thiolactone induced seizures in adult rats.

The aim of our study was to investigate the effects of ifenprodil and MK-801 on D,L-homocysteine thiolactone induced seizures in adult rats.Male Wistar rats were divided into following groups: 1. Saline-treated (C, n=10); 2. D,L-homocysteine thiolactone 8 mmol/kg, i.p. (H, n=7); 3. Ifenprodil 20 mg/kg i.p. (IF, n=8); 4. MK-801 0.5 mg/kg, i.p. (MK, n=8) and 5. Groups that received IF or MK 30 minutes prior to H (IFH, n=8 and MKH, n=8). Seizure behavior was assessed by incidence, latency, number and intensity of seizure episodes. Seizure severity was described by a descriptive scale with grades 0-4. Lethality in experimental group was recorded 90 min and 24 h upon D,L-homocysteine thiolactone administration.There were no behavioral signs of seizure activity in groups C, IF and MK.Pre-treatment with MK-801 (MKH) showed tendency to reduced incidence of convulsions, latency to the first seizure onset and the severity of seizure episodes, but statistical significance was not attained comparing to the H group. However, median number of seizure episodes was significantly decreased in MKH (p<0.05), comparing to the H group. On the other hand, ifenprodil (IFH) decreased the latency to the first seizure onset and increased the median number of seizure episodes (p<0.05). The majority of seizure episodes in IFH (72.1%, p<0.05) and MKH (73.1%, p<0.05) groups was grade 2 and significantly different comparing to the H (36.0%). Our findings suggest that MK-801 has a mild anticonvulsive effect on D,L-homocysteine thiolactone induced seizures in adult rats.

Oxidative stress in liver and red blood cells in acute lindane toxicity in rats.

The aim of our study was to determine the role and dynamics of oxidative and nitrosative stress, as well as superoxide dismutase (SOD) and catalase activity in the hepatocytes and erythrocytes in early phase of acute lindane intoxication. Male Wistar rats were divided into groups: control, dimethylsulfoxide and lindane-treated groups (L, 8 mg/kg, intraperitoneally). Animals were sacrificed 0.5 and 4 hours after treatment (L(0.5) and L(4) groups, respectively). Oxidative and nitrosative stress parameters and antioxidant enzymes were determined spectrophotometrically. Liver and plasma thiobarbituric acid reactive substances (TBARS) concentration were significantly increased 0.5 after lindane administration (p < .01), with subsequent additional rise within 4 hours (p < .01), while plasma nitrite + nitrate level was significantly higher only 4 hours after lindane treatment. Total liver SOD activity was significantly increased in L(4) group in comparison with control group (p < .01). In conclusion, oxidative and nitrosative stress play an important role in early phase of acute lindane hepatotoxicity. Antioxidant capacity of hepatocytes is partly increased, due to an adaptive increase in SOD activity.

Ethanol suppressed seizures in lindane-treated rats. Electroencephalographic and behavioral studies.

This study examines the effects of ethanol on lindane-induced seizures in rats. The animals were divided into following groups: 1. saline, 2. DMSO (dimethylsulfoxide), 3. lindane dissolved in DMSO in the dose of 4, 6 or 8 mg/kg (L(4), L(6) and L(8) groups, respectively), 4. ethanol 2 g/kg administered 30 min prior to lindane (protected groups AL(4), AL(6) and AL(8)) and 5. ethanol alone (2 g/kg). In order to determine ethanol concentration in plasma, blood samples were collected by cardiac puncture 30 and 60 min after ethanol injection. For EEG and power spectra recordings, electrodes were implanted into the skull. The lindane treatment resulted in a dose-dependent increase of seizure incidence and severity. The rats displayed severe seizure patterns characterized by high voltage spike-wave complexes, poly-spikes and sleep-like patterns in EEG, while the power spectra were intensively elevated in comparison to the corresponding controls. Ethanol alone led to increased EEG power spectra, which became dominant in the range of 0-4 Hz. For evaluation of anticonvulsant ethanol action we compared latency to seizure, incidence and seizure severity (scale from 0 to 4) in the examined groups. Ethanol diminished seizure incidence in AL(4) and AL(6) groups, decreased intensity of convulsions, and prolonged duration of latency period in AL(8) group. We observed suppression of the EEG signs of lindane-provoked epileptiform activity in AL(4) and AL(6), but not in AL(8) group. These results suggest that ethanol acted protectively on lindane-induced seizures and suppressed behavioral and epileptic EEG spiking activity.

Valproate and delta-sleep peptide display high efficacy against metaphit-induced audiogenic seizure in rats.

The effects of valproate (VPA) and delta sleep-inducing peptide (DSIP) on metaphit-induced generalized, audiogenic seizure in adult rat males were compared. The animals were i.p. injected with: (1) Saline; (2) metaphit (mp, 10 mg kg(-1)); 3. metaphit (10 mg kg(-1)) and 8 h later with DSIP (0.1, 0.2, 0.4 or 1.0 mg kg(-1)), 4. metaphit (10 mg kg(-1)) and 8 h later with VPA (50, 75 or 100 mg kg(-1)); 5. DSIP alone (1.0 mg kg(-1)) and 6. VPA, alone (100 mg kg(-1)). The rats were exposed to sound stimulation at hourly intervals and the behavior and EEG were analyzed. The EEG signals in metaphit rats appeared as a sleep-like pattern and spike-wave complexes with increased power spectra. Valproate and DSIP reduced the incidence of seizure and prolonged duration of latency in a dose-dependent manner. ED50 of valproate in the 1st hour after administration was 63.19 mg kg(-1) and that of DSIP 3.19 mg kg(-1) four hours after injection. This suggests that VPA, reached a peak of action immediately after the application, while DSIP had a prolonged action, mildly reducing, but not abolishing metaphit seizure. None of the applied VPA and DSIP doses eliminated the metaphit-provoked EEG signs of epileptiform activity.