Publications (3)6.05 Total impact
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Article: Role of ovarian hormones in T-cell homeostasis: From the thymus to the periphery.
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ABSTRACT: The study explored the putative role of ovarian hormones in the peripubertal remodelling of peripheral T-cell compartment. Ovariectomy at age of 1 month enhanced the peripubertal rise in CD4+ and CD8+ cell numbers in peripheral blood (PB) and spleen from 2-month-old rats. This reflected maintenance of thymopoietic efficiency at the prepubertal level (judging by numbers of the most mature CD4+ and CD8+ thymocytes and recent thymic emigrants) and alterations in T-cell survival/proliferation in the periphery. Compared with age-matched controls, the frequency of apoptotic cells among CD8+ peripheral blood lymphocytes (PBLs) and CD4+ and CD8+ splenocytes was diminished in ovariectomized (Ox) rats, at least partly, due to lower CD95 surface density. The diminished frequency of the apoptotic T splenocytes could also be associated with the rise in the amount of splenic IL-7 mRNA. Additionally, the latter finding was consistent with the augmented proliferation of CD4+ and CD8+ splenocytes. However, the enhanced proliferation of these cells could also be linked to the rise in IL-2 receptor surface density. This increase was related to the enhanced splenic TNF-α mRNA expression. Additionally, ovariectomy led to the phenotypic alterations in the major PBL and splenic T-cell subsets by diminishing/preventing the peripubertal changes in the frequency of cells at distinct stages of post-thymic differentiation/maturation (recent thymic emigrants, mature naïve and memory cells), and by decreasing the frequency of NKT cells within peripheral CD8+ subsets. In addition to numerical and phenotypic changes in T-cell compartment (due to the lack of ovarian hormone action at both the thymic and peripheral level), Ox rats exhibited a much larger delayed-type hypersensitivity (DTH) response compared with age-matched controls. This suggested the augmented T-cell-mediated immune response in Ox rats compared with aged-matched controls.Immunobiology 05/2012; · 3.20 Impact Factor -
Article: Neonatal androgenization affects the efficiency of β-adrenoceptor-mediated modulation of thymopoiesis.
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ABSTRACT: We tested the hypothesis that neonatal androgenization affects the efficacy of β-adrenoceptor (β-AR)-mediated fine tuning of thymopoiesis in adult female rats by modulating the thymic noradrenaline (NA) level and/or β-AR expression. In adult rats administered with 1000 μg testosterone enanthate at postnatal day 2 a higher density of catecholamine (CA)-synthesizing thymic cells, including thymocytes, and a rise in their CA content was found. In addition, in these animals increased thymic noradrenergic nerve fiber fluorescence intensity, reflecting their increased CA content, was detected. These changes were followed by an increase in thymic NA concentration. The rise in thymic NA content in thymic nerve fibers and cells was associated with changes in the expression of mRNA for enzymes controlling pivotal steps in NA biosynthesis (tyrosine hydroxylase, dopamine-β-hydroxylase) and inactivation (monoamine oxidase). In contrast, the thymic level of β(2)-AR mRNA on a per cell basis and the receptor surface density on thymocytes was reduced in testosterone-treated (TT) rats. As a consequence, 14-day-long treatment with propranolol, a β-AR blocker, was ineffective in modulating T-cell differentiation/maturation in TT rats. In conclusion, the study indicates the importance of the neonatal sex steroid milieu for shaping the immunomodulatory capacity of the thymic NA/β-AR signaling system in adult rats.Journal of neuroimmunology 09/2011; 239(1-2):68-79. · 2.84 Impact Factor -
Article: Thymus Changes in Experimentally Induced
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ABSTRACT: Experimental myasthenia gravis (EMG) was elicited in female AO rats, 8–12 weeks of age, by injection of 100 μg/rat Torpedo marmorata acetylcholine receptor (AChR)-protein incorporated in CFA. Bordetella pertussis, 24 × 109 microorganisms, rat, was injected simultaneously as additional adjuvant. Rats were sacrificed on the day of appearance of the clinical signs of EMG, and thymuses were used for histological analysis using stereologic method, and thymocyte subsets were estimated by flow cytometry. Two and three colour fluorescence was applied to determine DN (CD4-CD8-), DP (CD4 + CD8 +), SP-CD4+ (CD4+CD8-) and SP-CD8+ (CD4-CD8 +) subsets, as well as thymocytes expressing TCR α/β. Rats immunized with BSA and rats injected with saline were used as controls. From 56 rats immunized with AChR-protein, 44 rats developed the disease, between day 7 and 11 after immunization. Severity of disease varied from + to + + +. Stereologic analysis of tissue sections revealed a highly significant reduction of thymic cortex and hypertrophy of medulla in EMG thymuses. Similar, but very slight changes were observed in thymuses of rats immunized with BSA. Percentages of DN, SP-CD4+, and SP-CD8+ subpopulations were significantly increased, while the percentage of DP population showed a marked decrease. These preliminary data suggest an alteration of thymocyte maturational events. Whether these changes could be responsible for the initiation of autoimmunity, or are occurring as a secondary phenomenon, after EMG was already established following the injection of cross reactive antigen, is a matter for discussion.07/2009; 15(3):201-207.
