Glucocorticoid receptor mediates the expansion of splenic late erythroid progenitors during chronic psychological stress.

Stress evokes an integrated neuroendocrine response perturbing the homeostasis of different physiological systems. In contrast to well established physiologica linteractions between neuroendocrine and immune systems during chronic stress, there has been relatively little information on the effects of psychological stress on erythroid cells. Since stress-induced erythropoiesis occurs predominantly in the spleen, in the current study, we investigated the influence of chronic psychological stress on splenic erythroid progenitors and examined a role of glucocorticoid receptor (GR) in observed effect using a mouse model of restraint. The adult male mice were subjected to 2 hours daily restraint stress for 7 or 14 consecutive days and the role of GR in erythropoietic response to stress was assessed by pretreatment of mice with GR antagonist mifepristone 60 min prior to restraint. The results showed that chronic restraint stress induced an increase in spleen weight as well as in the cellularity of red pulp, as compared to controls. Furthermore, 7 and 14 days of restraint stress resulted in markedly increased number of both splenic early (BFU-E) and late (CFU-E) erythroid progenitors. Blockade of GR with mifepristone did not affect the number of BFU-E in stressed mice, but it completely abolished the effect of repeated psychological stress on CFU-E cells. Additionally, plasma corticosterone concentration was enhanced whereas the GR expression was significantly decreased within splenic red pulp after one and two weeks of stress exposure. Obtained findings suggest for the first time an indispensable role for GR in the expansion of CFU-E progenitors in the spleen under conditions of chronic psychological stress.

Stereological study of rat spleen following acute ethanol treatment.

To investigate the acute effect of ethanol (4 g/kg, i.p.) on spleen adult female Wistar rats were treated intraperitoneally with: a) ethanol (4 g/kg body wt), b) naltrexone (5 mg/kg body wt) followed 45 minutes later by ethanol (4 g/kg body wt) and c) naltrexone (5 mg/kg body wt) alone. Untreated and saline-treated rats were used as controls. Twenty hours after the ethanol treatment the animals were sacrificed and the spleens were removed. A piece of tissue from the central part of each organ was fixed in Bouin's solution. Paraffin sections were stained with hematoxylin-eosin and analysed using stereological measurements. The volume densities of the following tissue compartments: red pulp, white pulp (divided in follicles, periarterioral lymphatic sheath and marginal zone) and the connective tissue were determined. Stereological analysis also included parameters of follicles: the areal numerical density (the number of follicles per 1 mm2 of tissue section), the numerical density (the number of follicles per mm3 of tissue) and the mean follicle diameter. The immunoarchitecture of the spleen was preserved following acute ethanol treatment. Unlike other parameters that were unaffected, ethanol evoked a decrease in both volume density of follicle and the mean follicle diameter. Naltrexone pretreatment had no influence on ethanol-induced changes. The data obtained indicate that a single dose of ethanol has a profound effect on rat spleen affecting the follicles, but the mechanism of its action remains to be elucidated.

Naltrexone prevents ethanol-induced changes in rat thymus.

Ethanol is known to suppress the immune response, but the underlying mechanism accounting for the immunosuppression is not clearly elucidated yet. The purpose of this study was to investigate the effect of a single dose of ethanol on relative proportion of the four major rat thymocyte subsets and possible mechanism of its action. To this end, adult female AO rats were treated with: a) ethanol (2 or 4 g/kg, i.p.), b) naltrexone (5 mg/kg, i.p.) followed 45 min later by ethanol (2 or 4 g/kg, i.p.), c) naltrexone (5 mg/kg, i.p.), or d) only saline. Twenty hours later the rats were sacrificed and the proportion of the four major thymocyte populations defined by expression of CD4 and CD8 molecules was analyzed. Flow cytometric analysis revealed that ethanol evoked a decrease in the percentage of double-positive CD4+CD8+ thymocytes followed by a proportional increase in the percentage of single-positive CD4+CD8- cells. Naltrexone pretreatment prevented the ethanol-induced alterations in thymocyte subsets. The results clearly indicate that ethanol affects the process of intrathymic T-cell maturation. It seems that this effect might be mediated by an opioid-dependent mechanism.

Effect of a single dose of ethanol on granulopoiesis in female rats: relationship to phase of estrous cycle.

OBJECTIVE: The purpose of this study was to investigate the acute effect of ethanol (4g/kg, IP) on granulopoiesis at two phases of the rat estrous cycle, proestrus and diestrus Day 1. METHOD: The following parameters were estimated: in peripheral blood, the ethanol concentration, progesterone and estradiol levels, the total number of WBC and differential count: in the bone marrow, the total number of nucleated cells, the number of granulocyte-macrophage committed stem cells (CFU-GM) and differential count at various time points (5, 3, 6 and 20 hours) after treatment. The experiments were conducted twice and 4 to 7 rats were used per groups for each time point. RESULTS: The results indicated that a single dose of ethanol significantly increased the number of granulocytes and decreased the number of lymphocytes in peripheral blood. These changes were observed earlier at the proestrus compared to the diestrus Day 1, and were consistent with faster ethanol disappearance from blood during the proestrus. Additionally, the ethanol treatment induced a significant increase in progesterone levels at both phases. This effect was prolonged at the diestrus Day 1 and thus was also associated with differences in ethanol metabolism. In the bone marrow, the total number of nucleated cells and morphologically recognizable hematopoietic cells were not affected by ethanol treatment at any of the observed time points. However, at both phases of the estrous cycle ethanol treatment induced an increase in the number of CFU-GM derived colonies 20 hours after administration. CONCLUSIONS: The data obtained suggest active involvement of the granulocytic cell line in response to acute ethanol administration which is modulated by the current hormone status of the treated animals.

The possible mechanism of action of ethanol on rat thymus.

Alcohol is a known suppressant of the immune system and alcoholics frequently have impaired humoral and cell-mediated immunity. The purpose of this study was to investigate the effect of a single dose of ethanol on the thymus and the possible mechanism of its action. Adult female Wistar rats were divided into three groups which were treated with: (a) ethanol (4 g/kg i.p.), (b) naltrexone (5 mg/kg i.p.) and 45 min later with ethanol, (c) naltrexone alone. Untreated rats served as controls. The animals were killed 20 h after administration of alcohol. Thymuses were removed and fixed in Bouin's solution. Paraffin sections were stained with hematoxylin-eosin and analysed using stereological measurements. Our results showed that a single dose of ethanol significantly decreased the volume of the thymus especially affecting the cortex. This effect was blocked by pretreatment with naltrexone. Therefore, it seems that the effect of ethanol on the thymus is mediated by an opioid-dependent mechanism.

The insulin response to oral glucose, concentrations of total cholesterol, triglycerides and uric acid in women with idiopathic hirsutism.

The glucose and insulin responses to an oral glucose tolerance test, concentrations of total cholesterol, triglycerides and uric acid were evaluated in women with idiopathic hirsutism (IH). Clinical data and laparoscopy of the ovaries were used in diagnosis. According to body weight the patients were divided into two groups: obese (OB-IH) and non-obese (NO-IH). In the IH and NO-IH groups the glucose response was significantly greater than in the control group (p less than 0.05). The insulin response to oral glucose was significantly higher in the IH and OB-IH groups compared with the control group (p less than 0.01). The concentrations of total cholesterol and triglycerides were significantly increased in the IH and OB-IH groups compared to those of normal women (p less than 0.01). All groups had significantly higher levels of uric acid compared with the control group (p less than 0.01). The results of our study suggest that alterations of carbohydrate, lipid and uric acid metabolism are present in patients with IH and further studies are needed to establish their mechanisms.