Cell composition and ultrastructure of the thymus in offspring during changes in the hormonal background in the mother-fetus functional system

Micro- and ultrastructure has been studied in newborn rats, developed under conditions of an altered hormonal background in the functional system mother--fetus (FSMF), when hydrocortisone acetate is injected on the 17th-18th days of pregnancy, and at bilateral adrenalectomy of pregnant females. A number of similar changes in the offspring thymus are revealed under both procedure: the portion of mitotically dividing and blast forms of cells decreases, there is a certain tendency to increasing destructively altered cells and intensity of the processes in differentiation of cellular elements and subcellular structures, that is, evidently, depended on increasing contents of corticosteroids in the developing organism. When hydrocortisone acetate is injected to the pregnant rats, some amount of the drug can penetrate across the placenta and a superfluous concentration of glucocorticoids is created in the fetus blood. When adrenalectomy is performed in the pregnant rats, the main cause of elevated secretion of corticosteroids in the fetuses is, evidently, stimulation of the adrenals with their own ACTH, that is produced as a response to a decreased concentration of corticosteroids in FSMF. Nevertheless, in the fetal thymus reaction to the effects mentioned there are some differences. In the experiments with adrenalectomy in the pregnant rats, in the offspring thymus signs of degradation of lymphocytes and reticuloepitheliocytes are manifested more distinctly; that can be connected with a high concentration of endogenic corticosteroids in the fetus blood and with a qualitative composition of the hormones.     

The morphofunctional characteristics of the thymus in rat fetuses and progeny in venous occlusion]

Using histological and morphometrical methods, morphofunctional state of the thymus was studied in fetuses and offspring of rats in physiological pregnancy and under conditions of phlebo-occlusion. Phlebo-occlusion resulted in hypertrophy of the fetus, thymus and offspring, changes in structural zones and cellular reactions.     

Effect of altered hormonal balance in the mother-fetus system on body weight, the adrenal glands, thymus gland and peripheral blood leukocyte composition in the offspring

Pregnant rats have been injected intramuscularly with hydrocortisone-acetate or desoxycorticosterone-acetate (DOCA) for the III or the II-III trimesters of pregnancy. In the last case the animals are given not only greater doses of the hormones, but during a longer period. By the end of the pregnancy the drug dose decreases. In mother-rats after hydrocortisone injections the adrenals mass increases; after DOCA the body mass increases, and that of the adrenals drops. In the offspring hydrocortisone produces decline of the thymus and adrenals mass, as well as neutrophilic leucocytosis, lympho-, eosino-++- and monocytopenia. Just the opposite, DOCA results in lympho- and monocytosis, in increasing morphofunctional activity of monocytes. Common effects in hormonal action is demonstrated as underdevelopment of the adrenals, in decreasing thymus mass, in development of neutrophilic leucocytosis and eosinopenia. With increasing doses and duration of prenatal injections of corticosteroids in rats the mass of the adrenals and thymus drops even greater, stimulating effect of the hormones on the neutrophilic granulocytopoiesis decreases.     

Cellular composition and ultrastructure of the thymus of the newborn mouse after immunization of pregnant females with homologous brain antigens

Immunization is performed with 20% of water-saline extract of medulla oblongata on the 6th, 8th, 10th days of pregnancy (1 g per 200 g body mass). In the thymus cortical substance of newborn rats no statistically significant difference in content of small lympocytes, lymphoblasts and large lymphocytes, mitotically deviding cells is revealed as compared to the normal. The part of middle lymphocytes decreases up to 5.7 +/- 0.7% (control--10.0 +/- 1.7%). The content of distroying cells and fagocytic macrophages is increasing. In cytoplasm of one macrophage several fagocyted degenerating cells with pyknotic nuclei and destructively altered organells are often present. In the interlobular connective tissue an increased amount of degenerating forms of mast cells is noted. In the thymus medullary substance small lymphocytes are growing in number. Certain changes in vessels of the microcirculatory bed are revealed.     

Morphological characteristics of the thymus gland of albino rats after prenatal administration of indomethacin

By means of histological, histochemical and electron microscopical methods the thymus of white rat fetuses and offspring has been investigated during various age periods after indomethacin++ influence (2.5 mg/kg). In the fetuses retardation in separation of the gland parenchyma into lobules has been revealed. During the first two weeks of life the section area of the medulla decreases. Amount of lymphoid cells decreases; small and degenerating lymphocytes decrease in their number, while the part of lymphoblasts, middle lymphocytes and figures of mitosis increases. Enzymatic activity in the nervous structures of the organ is inhibited. Some essential disturbances of the intracellular structures are revealed; they demonstrate certain destructive changes. The data obtained show a decreasing function of the thymus after the prenatal influence of indomethacin++ during the first month of life, which is especially manifested during the first two weeks.     

Endocrine and lymphoid interrelations in rats with hereditary arterial hypertension

Functional state of the adrenals and structural organization of the thymus and lymph nodes in the rats with hereditary stress-induced arterial hypertension (HSIAH) have been investigated in the control and against the background of a prolonged staying under conditions of a moderate cold. In comparison with the initial population of Wistar rats, the test animals demonstrate an elevated level of corticosterone, decreased mass and size of the thymus, the size of the popliteal lymph nodes is increased at the expense of the structural components of the medulla. In 7 weeks of living in cold secretion of adrenal steroids in Wistar rats increases greatly and it is noticeably less in the HSIAH rats. Structural changes in the thymus are also insignificant, but reaction of the lymph nodes is important. Their size sharply diminishes at the expense of certain structural components of the medulla. A shift towards mature forms of the plasmocytic line cells takes place.     

Immune Effects of Nonylphenol on Offspring of Rats Exposed During Pregnancy

Effects of nonylphenol on immune system of male rats were examined. Dams were treated orally with nonylphenol at doses of 0, 20, 40, 80, or 200 mg/kg, respectively, from pregnant days 14 to 19. The offspring rats were investigated at postnatal day 60. Compared with the control groups, the doses of 80 and 200 mg nonylphenol/kg induced an obvious decrease in the absolute and relative weight of spleen and thymus. In the 200 mg/kg nonylphenol-treated group, the proliferative responses of murine spleen lymphocytes cultured in vitro were suppressed, Cytokine productions of interferon-gamma and interleukin-6 in serum were markedly lower than those in the control group. Histologically, the boundary between splenic red pulp and white pulp was unclear, expansion and congestion appeared in splenic sinus, lymphocytes in spleen and thymus dramatically reduced, and lots of focal necrosis cells were present. The results of this study show that nonylphenol can cross the placenta barrier, and that in utero exposure to 200 mg/kg/day nonylphenol can inhibit immune function in male offspring rats.     

Changes in the lymph nodes of vaccinated rats after prenatal exposure to an antibiotic

Changes of anatomical structures and dynamics of cell composition have been studied in lymph nodes of one-month-old rats, vaccinated with typhoid vaccine and sexta-anatoxin, and of rats vaccinated in a similar way, but their mothers have been given tetracycline at early and late periods of pregnancy. After vaccination in 1, 3 and 7 days lymphocytic, blastic, macrophagal, plasmocytic; mast cells, neutrophilic and eosinophilic reactions have been observed in lymph nodes. In the offspring of the rats, that have been given tetracycline during preimplantation and implantation periods (the 1st-7th days of pregnancy) contents of small, middle lymphocytes, plasmocytes, macrophages, mast cells do not change. Neutrophilic and eosinophilic reactions are revealed only in medullary cords, that demonstrates certain inhibition of the immunological function. In the rats, whose mothers have been given tetracycline during embryogenesis (on the 15th-20th days of pregnancy) vaccination results in a considerable increase of the reactive state of the lymph nodes.     

Ontogenesis of rat immune system: Proteasome expression in different cell populations of the developing thymus

Immune proteasomes in thymus are involved in processing of self-antigens, which are presented by MHC class I molecules for rejection of autoreactive thymocytes in adults and probably in perinatal rats. The distribution of immune proteasome subunits LMP7 and LMP2 in thymic cells have been investigated during rat perinatal ontogenesis. Double immunofluorescent labeling revealed LMP7 and LMP2 in thymic epithelial and dendritic cells, as well as in CD68 positive cells - macrophages, monocytes - at all developmental stages. LMP2 and LMP7 were also detected by flow cytometry in almost all thymic CD90 lymphocytes through pre- and postnatal ontogenesis. Our results demonstrate that the immune proteasomes are expressed in all types of thymic antigen presenting cells during perinatal ontogenesis, suggesting the establishment of the negative selection in the thymus at the end of fetal life. The observation of the immune proteasome expression in T lymphocytes suggests their role in thymocyte differentiation besides antigen processing in thymus.     

Manifestation of the neurotoxic effect of the organochlorine pesticide hexachlorobutadiene in the postnatal period of ontogeny in the rat

Daily peroral administration of chlororganic pesticide hexachlorobutadiene in doses 8.1 mg/kg (1/20 LD50) to pregnant rats results in certain ultrastructural changes of neurocytes and myelin fibers of the spinal cord both in the animals and their offspring (newborns and 1-2-month-old rats). By means of electron paramagnetic resonance (EPR) method, changes in intensity of the EPR-signals of free radicals in the spinal cord, ceruloplasmin of blood serum have been revealed in the experimental pregnant animals, as well as in 1-month-old rats (in the latter--in the brain, too). Gas-liquid chromatography reveals the preparation contents in the adrenals, heart, brain and spinal cord, in the uterus of the pregnant animals, as well as in corresponding organs of their offspring. Certain retardation in growth and decrease in body mass are noted in the offspring.     

Three-generation investigation on serotonin content in rat immune cells long after beta-endorphin exposure in late pregnancy.

Female rats were treated with beta-endorphin on the 19th day of pregnancy. Serotonin content of immune cells (peritoneal lymphocytes, monocyte-macrophage-granulocyte group (mo-gran), mast cells, blood lymphocytes, granulocytes and monocytes, thymus lymphocytes) were studied in the mothers (P-generation four weeks after delivery), in the male offspring (F1) generation (at seven weeks), in the female offspring (four weeks after their own delivery) and in their offspring (F2 generation, at seven weeks). P-mother cells' serotonin content was not influenced by endorphin treatment, while F1 generation's mo-gran and blood lymphocyte serotonin content was reduced (in contrast, histamine content of mo-gran increased). Four weeks after delivery, an increase in serotonin content was observed in the F1 generation in the peritoneal lymphocytes and mast cells as well as in blood lymphocytes. In contrast, serotonin content was reduced in blood granulocytes and monocytes. In the F2 (grandson) generation, a reduction in mast cell serotonin content and sensitization of blood and thymic lymphocytes to repeated endorphin treatment was provoked. The significant changes were more expressed in the F2 generation compared to F1, also appearing earlier. The results unequivocally suggest that the increase in endorphin levels during late pregnancy can cause permanent changes in the F1 and F2 generations, which means that the imprinting effect can be transgenerationally transmitted.     

Fluorescence study of thymus lymphocytes of X-irradiated mice and their progeny.

The mechanisms of changes in the ultra-violet fluorescence (U.V.F.) intensity of mouse thymus lymphocytes 24 hours and 30 days after whole-body X-irradiation have been studied. The thymus lymphocytes of the first generation offspring (F1) from X-irradiated males and unirradiated females were also investigated. At 24 hours after irradiation the U.V.F. intensity decreased for small doses (50 and 65 rad) and increased for doses of more than 100 rad. The changes in U.V.F. intensity were related to a size-independent mechanism. It was found that the U.V.F. increase for doses of 100-700 rad was not connected with the appearance of non-viable (eosin test) cells. The changes in U.V.F. intensity and cellular composition of the thymus were the same 30 days after irradiation and for F1 mice. The increase in U.V.F. intensity was about 14% and did not depend on dose between 50 and 500 rad. About one-half of this increase was connected with an increase in the proportion of medium and large lymphocytes in the thymus. The rest of the effect was related to a size-independent mechanism.     

Perinatal supplementation with thymoquinone improves diabetic complications and T cell immune responses in rat offspring

Background

Epidemiological studies have shown that the offspring of mothers who experience diabetes mellitus during pregnancy are seven times more likely to develop health complications later in life compared to offspring born to nondiabetic mothers.

Aim of the study

We investigated whether supplementation with a natural antioxidant (thymoquinone; TQ) in female rats with streptozotocin (STZ)-induced gestational diabetes (GD) improved diabetic complications and T cell immune responses in their offspring.

Methods

Three groups of female rats were tested: nondiabetics, diabetics treated with TQ during pregnancy and lactation periods and diabetics that were not treated with TQ (n = 10 female rats in each group).

Results

Our data demonstrated a significant decrease in the numbers of neonates born to diabetic rats compared with those born to control rats. GD led to macrosomic pups with several postpartum complications, such as a significant increase in plasma levels of the pro-inflammatory cytokines IL-1β, IL-6, and TNF-α (but not of IL-10); a marked decrease in the plasma level of IL-2; a marked reduction in the proliferative capacity of superantigen (SEB)-stimulated T-lymphocytes; and an obvious reduction in the number of circulating and thymus homing T cells. TQ supplementation of diabetic mothers during pregnancy and lactation periods had an obvious and significant effect on the number and mean body weight of neonates. Furthermore, TQ significantly restored the IL-2 level and T cell proliferation and subsequently rescued both circulating and thymus homing T cells in the offspring.

Conclusions

Our data suggest that nutritional supplementation of GD mothers with the natural antioxidant TQ during pregnancy and lactation periods improves diabetic complications and maintains an efficient T cell immune response in their offspring, providing a protective effect in later life.     

Mast cell changes in the organs of the immune system under physical loading

By means of histological and morphological methods reaction of mast cells has been studied in the thymus and inguinal lymph nodes of mature non-inbred white male rats, subjected to systematic physical loadings (daily swimming) with increasing time from 5 up to 100 min during 5 months. Morphological changes in the organs studied and manifestation of the mast cell reaction essentially depend on the degree of the animals' adaptation to the loading. In the animals adapted to swimming, decreasing area, occupied by the connective tissue elements, in comparison to that in the control--increasing cortical area, increasing number of lymphoid cells, decreasing number of the mast cells in the inguinal lymph nodes--are noted. When the adaptation of the animals to the loading is insufficient, outgrowth of the connective tissue elements, decreasing cortical zone, impoverishment of the parenchyma with lymphocytes occur. The number of the mast cells increases, many of them are at the state of degranulation.     

Developmental changes in the cellular composition of the chicken thymus

The cellular composition of the chicken thymus has been analyzed at different ages by using size distribution analysis in combination with preparative cell electrophoresis. The combination of these two physical methods was able to clearly resolve two major cellular subpopulations in the young chicken thymus and suggested the exsistence of a third one. Microscopically, all three cell types appeared to be small lymphocytes. Medium and large lymphocytes are not detected as distinct peaks by the settings used.The analysis revealed dramatic developmental changes in the cellular composition of the thymus. The adult chicken thymus, which is known to have practically no cortex, contained mainly one relatively large cell type. This cell type may, therefore, represent the medullary lymphocyte and may be active in graft-versus-host (G.v.H.) reactions. In the early postnatal thymus that is known to contain little graft-versus-host reactivity this larger cell type was not detectable. Instead, smaller cell types were found to be dominant. The developmental shift from smaller to larger cells was discontinuous. Before thymus involution at 16 weeks of age, smaller and larger cells were both found to be present and to have the same typical size and electrophoretic mobility that is characteristic for the postnatal or the adult chicken thymus, respectively. Size and electrophoretic mobility were therefore taken as markers indicating distinct cellular subpopulation in the thymus.     

Immunomorphological analysis of prolonged intoxication by low doses of herbicide simazine]

Dynamic investigation of several immunologic data and complex morphologic study of the thymus of rats fed for a long time (6 months) by very low doses of herbicide simazine have been carried out. Chronic simazine treatment resulted in the development of the secondary immunodeficient state with the damage of T lymphocytes. The morphologic signs of this process were the disarray in thymus structure (dystrophic changes and intercellular contact break of nurse cells, sclerosis of microvessel walls and stromal elements), severe decrease of the T lymphocyte number in peripheral blood, inhibition of phagocytosis reaction of neutrophils.     

Effects of patulin on thymus capillary of rats

Patulin is a mycotoxin that is produced by species of Penicillum, Aspergillus, and Byssochylamys molds that may grow on a variety of foods including fruit, grains and cheese. Patulin, at a dose of 0.1 mg kg(-1) bw day(-1) was administered orally to growing male rats aged 5-6 weeks for a period of 60 or 90 days. The dose of patulin used in the present study was based on estimated human exposure levels. At the end of these periods, the thymus glands of patulin-treated and control Wistar rats were removed and ultrastructural changes in capillary cells of the thymus of patulin-treated Wistar rats were determined by electron microscopy. The walls of thymus capillaries of the 60-day patulin-treated rat groups (P-60) exhibited degeneration observable in electron microscopic sections. For example, loss of cytoplasm and mitochondrial cristae of cells, swollen endothelial cells, increased thickness of the basement membrane, closed lumen of capillaries, accumulation of fibrous material at the periphery of the capillaries and nuclear anomalies were seen in these sections. Such degeneration and changes were also observed in sections of capillaries of the 90-day patulin-treated rat groups (P-90). The levels of degeneration of endothelial cell nucleus of P-90 were greater than those of P-60. This study demonstrated the ultrastructural degeneration of thymus capillary cells of patulin-treated rats. The results obtained from this study may provide a guide to research dealing with the toxic effects of patulin on tissue and organ ultrastructure.     

Enriched Environment-induced Maternal Weight Loss Reprograms Metabolic Gene Expression in Mouse Offspring

The global prevalence of weight loss is increasing, especially in young women. However, the extent and mechanisms by which maternal weight loss affects the offspring is still poorly understood. Here, using an enriched environment (EE)-induced weight loss model, we show that maternal weight loss improves general health and reprograms metabolic gene expression in mouse offspring, and the epigenetic alterations can be inherited for at least two generations. EE in mothers induced weight loss and its associated physiological and metabolic changes such as decreased adiposity and improved glucose tolerance and insulin sensitivity. Relative to controls, their offspring exhibited improved general health such as reduced fat accumulation, decreased plasma and hepatic lipid levels, and improved glucose tolerance and insulin sensitivity. Maternal weight loss altered gene expression patterns in the liver of offspring with coherent down-regulation of genes involved in lipid and cholesterol biosynthesis. Epigenomic profiling of offspring livers revealed numerous changes in cytosine methylation depending on maternal weight loss, including reproducible changes in promoter methylation over several key lipid biosynthesis genes, correlated with their expression patterns. Embryo transfer studies indicated that oocyte alteration in response to maternal metabolic conditions is a strong factor in determining metabolic and epigenetic changes in offspring. Several important lipid metabolism-related genes have been identified to partially inherit methylated alleles from oocytes. Our study reveals a molecular and mechanistic basis of how maternal lifestyle modification affects metabolic changes in the offspring.     

Influence of castration on development of the thymus in neonatal male rats.

The influence of castration on the development of the thymus in neonatal rats was studied to elucidate when after birth the thymus comes under inhibitory regulation by the testis in rats. The relative and absolute weights of the thymus were measured five days after castration these cases. No excessive changes in the weights of the thymus with castration were observed by 31 days after birth. Significant changes in the thymus appeared in the relative weight at 36-day-castration. The absolute weight of the thymus was also significantly increased after 41-day-castration. These findings suggest that in rats the inhibitory regulation of the thymus by testis development does not appear before at least 31 days of age.     

Morphologic changes in the thymus and lymphoid nodules of the appendix of the white rat subjected to increasing physical loads

By means of histological and morphometrical methods the thymus and appendage have been studied in male white rats subjected to a dosed physical loading (swimming). The physical loading is accompanied with essential changes in structure and cell composition of the immunogenic organs. The rate and character of the changes depend on the adaptability level of the animal's organism to the physical loading. At adaptation to the loading, the process of age involution of the thymus decelerates, amount of lymphoid nodules in the appendage increases, comparing the control parameters, contents of lymphocytes noticeably increase in all zones of the lymphoid nodules. When adaptation to the physical loading is not sufficient, the rate of the thymus involution sharply increases, while in the appendage the number of the lymphoid nodules decreases. However, in some animals at a sharp involution of the thymus, the changes in the appendage do not differ from the control ones.