Protective effect of pregnanolone against lipoperoxidation and free radicals generation induced in hypothalamus of ovariectomized rats submitted to CO2 exposure

Exploratory Investigation of Biomarker Candidates for Suicide in Schizophrenia and Bipolar Disorder

Background: Clozapine and lithium increase neurosteroids in rodents, and both drugs demonstrate antisuicidal actions. We therefore hypothesized that neurosteroid levels may be reduced in patients with schizophrenia or bipolar disorder who completed suicide. Aims: To investigate neurosteroid levels in the parietal cortex and posterior cingulate in schizophrenia and bipolar patients who died by suicide, and compare them with patients with these disorders who died of other causes. Method: Neurosteroid levels were quantified by gas chromatography/mass spectrometry in the parietal cortex and posterior cingulate. Mann–Whitney analyses were conducted in exploratory post hoc analyses to investigate neurosteroids as possible biomarker candidates for suicide. Results: The study showed that pregnenolone was significantly decreased in the parietal cortex in the combined group of patients with schizophrenia or bipolar disorder who died by suicide (n = 13) compared with patients with these disorders who died of other causes (n = 17, p = .02). Pregnenolone levels were also lower in the parietal cortex in the individual group of schizophrenia patients who died by suicide (n = 4) compared with schizophrenia patients who died of other causes (n = 11) p = .04). Conclusion: Pregnenolone alterations may be relevant to the neurobiology of suicide in schizophrenia and bipolar disorder.

The effects of polymicrobial sepsis with diabetes mellitus on kidney tissues in ovariectomized rats

OBJECTIVES

Sepsis model was used to understand the role of sustained hyperglycemia and ovariectomy, either separately or concomitantly, on the response of the activity of the nuclear factor kappa B (NF-kappaB) and the oxidative response in kidney.

SUBJECTS

Polymicrobial sepsis was induced by cecal ligation and puncture (CLP). Diabetes was induced in female rats using administration of alloxan. The rats were divided into five groups: sham control (group 1), ovariectomy (group 2), ovariectomy + sepsis (group 3), ovariectomy + diabetes (group 4), and ovariectomy + diabetic + sepsis (group 5).

RESULTS

In kidney tissues, the levels of lipid peroxidation (LPO) and glutathione (GSH) and the activity of catalase (CAT) were higher for groups 3, 4, 5 than the control groups. Superoxide dismutase (SOD) activity was lower for groups 3, 4, 5 than the control groups. We determined that CLP produced injury evident in the kidneys of rats when compared to the control group, whereas the severity of the injury was higher in the diabetes + ovariectomy + CLP group when compared to the CLP group. In immunohistochemical staining, we determined that CLP operation increased NF-kappaB activation. In the ovariectomized, septic, and diabetic group, NF-kappaB activation was significantly higher than other groups.

CONCLUSIONS

Hyperglycemia and ovariectomy severely increased NF-kappaB activation and oxidant levels with the stages of our sepsis model. Ovariectomy resulted in general changes in metabolism, which are seen in the kidney with diabetes under sepsis conditions.

Lipid peroxidation in ovariectomized and pinealectomized rats: the effects of estradiol and progesterone supplementation

In the present study, we investigated the effect of estradiol and progesterone supplementation on oxidant and antioxidant parameters of renal tissue in ovariectomized and pinealectomized rats. The study was carried out on 36 adult, Sprague-Dawley strain female rats, 6 months of age and weighing 200-250 g. The rats were divided into six groups, each group included six rats: Group 1: Sham-ovariectomized (Sham-Ovx); Group 2: Ovariectomized (Ovx); Group 3: Ovx and estradiol (E) and progesterone (P) supplemented (Ovx+E-P); Group 4: Ovariectomized and sham pinealectomy (Ovx+sham Pnx); Group 5: Ovariectomized+Pinealectomized (Ovx+Pnx); Group 6: Ovariectomized+Pinealectomized+Hormone Supplemented group (Ovx+Pnx+E-P). The levels of malondialdehyde (MDA), reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) were analysed in renal tissues of rats. The highest and the lowest levels of MDA were determined in Groups 5 and 1 respectively (p < 0.001). However, GSH and GSH-Px levels demonstrated statistically important decreases in groups 2, 4, 5 (p < 0.001). The findings of this study demonstrate that ovariectomy leads to oxidative damage in renal tissue. Pinealectomy in addition to ovariectomy greatly increases the oxidative damage. However, female sex hormones supplementations to the Ovx and/or Ovx+Pnx rats protected against lipid peroxidation by activating the antioxidant system.

Lipid peroxidation in liver tissue of ovariectomized and pinealectomized rats: effect of estradiol and progesterone supplementation

The present study aimed to determine the effect of estradiol-progesterone supplementation and pinealectomy on lipid peroxidation of liver tissue in ovariectomized rats. The study was carried out on 36 adult Sprague-Dawley female rats, which weighed 200-250 g. The rats were divided into 6 groups: Group 1: Sham Ovariectomy (Sham-Ovx), Group 2: Ovariectomy (Ovx), Group 3: Ovx + Estradiol-Progesterone supplementation (Ovx + H), Group 4: Sham Pinealectomy and Ovx (Sham Pnx -Ovx), Group 5: Ovx -Pnx, Group 6: Ovx -Pnx + H. Malondialdehyde (MDA), reduced form of glutathione (GSH) and glutathione peroxidase (GSH-Px) levels were determined in liver tissue of rats. The highest MDA levels and the lowest GSH-Px levels were determined in the ovariectomized-pinealectomized group, whereas the lowest MDA was in the Sham-Ovx group, and the highest GSH-Px levels were found in the Sham-Ovx and Ovx + Hormone supplemented group. Furthermore, the highest GSH levels were in group 1 and lowest levels were in group 5. The findings of this study demonstrate that ovariectomy led to lipid peroxidation in liver tissues of rats. Pinealectomy in addition to ovariectomy, increases lipid peroxidation, but, estradiol and progesterone supplementations to the ovariectomized-pinealectomized rats protect against lipid peroxidation to a significant extent.

Hypoxia Potentiates Endotoxin-Induced Allopregnanolone Concentrations in the Newborn Brain

BACKGROUND

Allopregnanolone is a neurosteroid produced in the brain that can alter the excitability of the CNS. Neurosteroids have neuroprotective properties, and their elevation in response to stress may protect the newborn brain following infection or hypoxia. Infection, particularly of the respiratory tract, may lead to episodes of hypoxia. Infection and hypoxia have been identified as factors contributing to neonatal morbidity and mortality.

OBJECTIVES

To determine the effect of acute episodes of hypoxia alone or in combination with lipopolysaccharide (LPS) exposure on plasma and brain allopregnanolone concentrations in lambs 10-21 days old. Also, to examine plasma levels of cortisol and the cytokines, tumour necrosis factor-alpha and interleutkin-6 after these challenges.

RESULTS

Allopregnanolone concentrations in the brain were markedly increased after hypoxia. Hypoxia following prior LPS treatment resulted in greater increases in brain allopregnanolone concentrations compared to either the LPS or hypoxia treatment alone. Importantly, brain regions unaffected by LPS or hypoxia alone (thalamus/hypothalamus, cerebellum) showed significant increases of allopregnanolone content following the combined LPS and hypoxia treatments. Plasma tumour necrosis factor-alpha and interleukin-6 concentrations were increased after LPS treatment with and without hypoxia, but not by hypoxia alone. In contrast, plasma cortisol concentrations were increased after both stressors.

CONCLUSIONS

These results show that the brain of young lambs readily responds to physiological stress by increased production of allopregnanolone. This response may protect the developing brain from the cytotoxicity following hypoxic and infectious episodes.

Ovariectomy exacerbates oxidative stress and cardiopathy induced by adriamycin

Ovarian hormone depletion in ovariectomized experimental animals is a useful model with which to study the physiopathological consequences of menopause in women. It has been suggested that menopause is a risk factor for the induction of several cardiovascular disorders. In the present study we analyzed the effects of ovarian hormone depletion by ovariectomy (OVX) in a model of oxidative stress and cardiopathy induced by adriamycin (AD). To evaluate these effects, we measured parameters related to cardiac damage (creatinine kinase, lactate dehydrogenase, aspartate aminotransferase and alanine aminotransferase) and oxidative stress (malondialdehyde, catalase, superoxide dismutase, glutathione peroxidase, reduced glutathione, nitric oxide and carbonyl proteins) in cardiac tissue and erythrocytes. OVX was found to alter all markers of oxidative stress and cell damage in cardiac tissue. Similarly, the OVX-derived loss of ovarian hormones enhanced cardiac damage and oxidative stress induced by AD. Our results suggest that antioxidant status in cardiac tissue and erythrocytes is seriously compromised by OVX during the cardiomyopathy induced by AD in experimental animals. In conclusion, the absence of hormones caused by OVX or menopause may induce or accelerate pre-existing cardiovascular dysfunctions.