Rat Thymus Research Articles

The influence of in utero exposure to formaldehyde on newborn rat thymus structure

Aim. To study the structure of the thymus of newborn rats born from female rats exposed to inhalation of formaldehyde during gestation.
 Materials and Methods. The work was carried out on 72 white outbred rats of the first day of postnatal development. The first group consisted of newborn rats (n=37) the offspring of six rats that were exposed to formaldehyde (FA) in concentration of 2.766 mg/m3 during the entire period of pregnancy. FA exposure was given once a day for 60 minutes in a 1 m3 exposure chamber. The second group included control animals (n=35), which were kept in conditions similar to those of the experimental groups with the exclusion of the effect of FA. In the newborn rats, the body mass and the absolute and relative mass of the thymus were determined. The structure of thymus was studied in a light optical microscope. The number of cells in the cortex and medulla of the thymus was counted over an area of 2500 m2.
 Results. The body mass and absolute mass of thymus of the newborn rats of the first group showed a statistically significant reduction against control values. The differences between the values of relative mass of thymus in the compared groups were insignificant. The number of cells in the cortex and medulla of the thymus under the influence of FA did not show any significant changes.
 Conclusion. The effect of inhalation of FA on the organism of pregnant rats during the entire gestation period consists in a decrease in the body mass and in the absolute mass of the thymus of newborn rats. With this, the relative mass of the thymus did not undergo significant changes. The thymus structure in the light microscope did not show any significant changes either.

Bone marrow mesenchymal stem cells improve thymus and spleen function of aging rats through affecting P21/PCNA and suppressing oxidative stress.

Bone marrow mesenchymal stem cells (BMSCs) have been considered to be an important regulator for immune function. We aim to prove the function improvement of aging spleen and thymus induced by BMSCs and unfold the specific mechanisms. Aging animal model was established using D-galactose. The morphological changes of spleen and thymus tissues were observed using hematoxylin-eosin staining and transmission electron microscopy. Key cytokines in the serum were measured with enzyme linked immunosorbent assay. Protein and mRNA levels of P16, P21, and PCNA were detected using western blotting and RT-qPCR. Special markers of BMSCs were identified using flow cytometry, and successful induction of BMSCs to steatoblast and osteoblasts was observed. Compared to aging model, BMSCs significantly increased the spleen and thymus index, improved the histological changes of spleen and thymus tissues. A remarkable increase of ratio between CD4+T cells and CD8+T cells, level of IL-2 was achieved by BMSCs. However, BMSCs markedly inhibited the content of IL-10, TNF-a, P16, and P21 but promoted PCNA. Significant inhibition of oxidative stress by BMSCs was also observed. We demonstrated that BMSCs significantly improved the tissue damage of aging spleen and thymus, BMSCs may improve aging organs through influencing cytokines, oxidative stress, and P21/PCNA.

Rat peripheral blood leukocyte subset composition, hemogram, lymphoid organ and body morphometry after exposure to biologically active substances derived from Hirudo verbana saliva

Medical community has noted that the prevalence of allergic diseases by steadily tends to rise resulting from using synthetic drugs ecological catastrophe. In this regard, more and more attention is increasingly being paid to natural therapeutic approaches, one of which is based on applying hirudotherapy. There were used 40 pubescent outbred female rats and their 200 pups born during experiment. In particular, female rats underwent leeching in the subscapular region 2 weeks before and 2 weeks after mating by applying medical leeches weighing 400 ± 10 mg. Next, relevant progeny was examined at day 1, 15, 30, 45, and 60 after birth, whereas female rats– after weaning. Experiment was designed to assess diverse parameters in accordance with the age-related rat development: newborn pups – 1-5 days old, day 6-21 – suckling period, day 22-50 – onset of puberty, day 60 onward – puberty. After measuring body morphometric parameters, female rats were sacrificed by decapitation under ether narcosis on day 60, whereas rat pups – at various time points. followed by autopsy and collecting blood sample into a sterile centrifuge tube by using 2% Spofa crystalline heparin (8:1) to be further examined by standard assays: morphometry of rat body, spleen and thymus; measuring total leukocyte count; CBC with differential; RBC; hemoglobin level; color index. Statistical data processing was performed by calculating arithmetic mean, error of arithmetic mean, standard deviation by using SPSS version 21.0 and Microsoft Office Excel 2010 software. Significance of differences was estimated by using Student's t test, and set at p≤0.05. Our study demonstrated medical leech saliva components applied during hirudolotherapy exerted an immune-augmenting effect of on morphometric body, thymus and spleen parameters. Moreover, starting from day 1, total leukocyte count, RBC, and hemoglobin level were increased in the experimental group. Moreover, we convincingly demonstrated a stimulatory effect of medical leech saliva components on histogenetic reactions at various ontogenetic stages in both female rats and their progeny. In the former, such morphogenetic effect was maintained for more than 70 days after the last leeching: on week 2 after mating and 30 days after delivery. Changes in morphological and hematological evidence about enhanced morphogenetic function of immune system in response to saliva-derived biologically active substances released by medicinal leeches.

Morphological Changes of the Thymus of the Juvenile White Rats Exposed to the Inhalation of Formaldehyde

The aim of the article is to study the morphological features of the thymus of the white rats exposed to the inhalation of formaldehyde.Material and methods. 72 white male rats with an initial body weight of 130–150 g were were exposed to formaldehyde at a concentration of 2.766 mg/m3. Exposures were carried out once a day during 60 minutes. Exposure durations were 10, 20, 30, 60 and 90 days. We separately studied the thymus of rats, which, after 60 days of exposure to formaldehyde, were kept for 30 days in standard vivarium conditions (rehabilitation group). The structure of the thymus was studied by light microscopy.Results. The number of cells in an area of 2500 μm2 of the subcapsular zone in animals exposed to formaldehyde for 10, 20, and 30 days was 131.19±4.20, 135.65±7.74, and 135.35±10.83, respectively, which was less than the control set by 4.35%, 4.68% and 3.72%, respectively. After 40 and 60 days, this indicator was below the control by 8.90% and 9.63%.Conclusion. Inhalation of formaldehyde reduces the area of the thymus cortex. Phenomena of inversion of the cortex and the medulla are observed. Under the influence of formaldehyde, a picture of so called «starry sky» is observed in the cortical substance of the thymus. A decrease in the severity of changes in the thymus of rats belonging to the rehabilitation group, in comparison with animals that received 90 exposures, indicates that the changes are reversible.

Postnatal development of metallophilic macrophages in the rat thymus.

Metallophilic macrophages (MMs) are a distinct cell type of the rodent thymus. Our previous research has focused on the morphological characteristics of MMs, as well as on the molecular mechanisms involved in the development and tissue positioning of these cells. However, the postnatal development of MMs has not been sufficiently studied. In the present study, we investigated the positioning of MMs in the rat thymus between postnatal day 0 (P0) and P30. On P0, MMs were evenly distributed all over the thymic tissue-that is, the cortex, cortico-medullary zone and medulla. From P0 to P15, the number of MMs in the thymic cortex significantly decreased, and after P15, this number did not change. Thus, the present study shows that on P15, MMs almost completely disappear from the thymic cortex and show their adult position in the cortico-medullary zone and in the medulla.

IMMUNOTROPIC EFFECTS OF IVERMECTIN IN PRODUCTIVE AND LABORATORY ANIMALS

The aim of this work was to identify the immunotropic effects of ivermectin in productive and laboratory animals in real and simulated conditions. The studies were carried out on hybrid pigs at the age of 144 days reared in an industrial pig complex and on Wistar rats aged 5 months with a body weight of 230 - 250 g. For the experiments there was used acaricide insecticide Ivermin (Biovet Drwalew S.A., Poland), which was administered to pigs once subcutaneously in a dose of 0,2 mg / kg and to rats in a tenfold therapeutic dose. Blood samples were taken from pigs either before the administration of Ivermin, and 1, 3, 7, 14 and 30 days after the administration. The level of immunoglobulins (IgG, IgM, IgA) was determined in serum by the method of radial immunodiffusion according to Mancini. To prepare histopreparations, samples of thymus, spleen and lymph nodes were taken from rats 14 days after the administration of the preparation. For statistical processing of experimental data, Student’s T-test for dependent samples has been used.When studying pigs’ blood serum, a decrease in the content of IgG was established in all periods of the study. A decrease in level of IgM and IgA was marked in 7 days after the experiment started. At the end of the experiment, the IgG level remained below the background value by 16,4%; IgM - by 15,2%; IgA – by 33%. In the rat thymus, a narrowing of the cortical substance was observed when a toxic dose of Ivermin was injected, with the splenic follicles reduced, and reproduction centers faintly pronounced. Hemosiderin accumulation was detected around the follicles. In the mesenteric lymph nodes, there was found a thickening of the capsule and the expansion of trabeculae. Cortical substance was narrow and paracortical zone was wide. The results of the study indicate a high risk of immunotoxic effect of ivermectin.

The Effect of Plectranthus amboinicus Lour Spreng Ethanolic Extract on Relative Organ, Body Weights Changes, and Hematology Profile in Wistar Rats Treated with 7,12Dimethylbenz(a)anthracene

This study aims to examine the protective properties of ethanol extract Plectranthus amboinicus (EEP) leaves on body weight gain, the relative weight of liver, kidney, lung, spleen, thymus and haematological profile of rats induced by 7,12Dimethylbenz(a)anthracene (DMBA). Used 25 female rats, divided into five groups namely NC (given Carboxymethyl cellulose (CMC) 1%), PC (given DMBA 20 mg/kg body weight), T1, T2, and T3 were each given DMBA 20 mg/kg body weight once every four days for 32 days and EEP 175, 350, and 700 mg/kg body weight given every day from day 33 to 59. Both the DMBA and EEP are given orally using a gastric gavage. On day 60, rats were killed by neck dislocation, bood collected in EDTA tubes for hematological analysis, rats are dissected to obtain liver, kidney, lung, thymus, and spleen organs. Data were analyzed with one way Analisys of varians (ANOVA). The results of this study indicate that EEP in T1, T2 and T3 treatments has no effect on weight loss compared to PC. There was no effect of EEP on the relative weight of the liver, kidneys, spleen, thymus and lungs. EEP increased the number of erythrocytes, leukocytes and platelets in rats that had DMBA

Changes in Lymphocyte Composition and Functionality After Intensive Training and Exhausting Exercise in Rats.

Exhausting exercise can have a deleterious effect on the immune system. Nevertheless, the impact of exercise intensity on lymphocyte composition and functionality remains uncertain. The aim of this study was to establish the influence of intensive training on lymphoid tissues (blood, thymus, and spleen) in Wistar rats. Two intensive training programs were performed: a short program, running twice a day for 2 weeks and ending with a final exhaustion test (S-TE group), and a longer program, including two exhaustion tests plus three runs per week for 5 weeks. After this last training program, samples were obtained 24 h after a regular training session (T group), immediately after an additional exhaustion test (TE group) and 24 h later (TE24 group). The composition of lymphocytes in the blood, thymus, and spleen, the function of spleen cells and serum immunoglobulins were determined. In the blood, only the TE group modified lymphocyte proportions. Mature thymocytes’ proportions decreased in tissues obtained just after exhaustion. There was a lower percentage of spleen NK and NKT cells after the longer training program. In these rats, the T group showed a reduced lymphoproliferative activity, but it was enhanced immediately after the final exhaustion. Cytokine secretion was modified after the longer training (T group), which decreased IFN-γ and IL-10 secretion but increased that of IL-6. Higher serum IgG concentrations after the longer training program were detected. In conclusion, the intensive training for 5 weeks changed the lymphocyte distribution among primary and secondary lymphoid tissues and modified their function.

THE EFFECT OF АFOBAZOL ON THE NEUROAMINE STATUS OF THE THYMUS OF WHITE RATS

Often used in medical practice drug Afobazol has a wide range of actions. The paper describes the morphological changes of neuroamine-containing structures of the thymus of white rats with long-term (8 weeks) afobazole administration. By fluorescent histochemistry was determined by the content of catecholamines, histamine, and serotonin in the structures of the thymus. Under the influence of afobazole, the luminescent picture in the structures of the thymus changes, the clear boundary between the cortical and medullary substance of the thymus lobe is erased. The introduction of Afobazole leads to a decrease in the concentration of biogenic amines in premedullary GLA and an increase in the concentration in the microenvironment, which indicates a decrease in the amino-producing properties of these cells and the release of neurotransmitters from GLA.

INFLUENCE OF SEMAX ON THE INTENSITY OF LIPID PEROXIDATION IN IMMUNOCOMPETENT ORGANS IN THE CONDITIONS OF “SOCIAL” STRESS

This study is devoted to an experimental study of the effect of Semax (Met-Glu-His-Phe-Pro-Gly-Pro) on the intensity of lipid peroxidation of the thymus and spleen lipids of male rats under conditions of “social” stress. “Social” stress in animals was modeled by the formation of aggressive and submissive behavior of males in the conditions of distant sensory contact. The intensity of lipid peroxidation (LPO) in the thymus and spleen was determined by spectrophotometry using three indicators: the initial level of products reacting with thiobarbituric acid (TBA-reactive products), the rate of spontaneous and induced by ascorbate and iron ions of LPO. “Social” stress is accompanied by an increase in peroxidation processes in immunocompetent organs, which contributes to the development of stress-induced functional disorders of the immune system. Against the background of Semax administration under “social” stress, its pronounced corrective effect on lipid peroxidation rates is observed, as evidenced by a decrease in spleen and thymus tissue homogenates of male rats in the initial level of TBA-reactive products, as well as spontaneous and ascorbate-dependent levels of lipid peroxidation.

Exosomes derived from statin-modified bone marrow dendritic cells increase thymus-derived natural regulatory T cells in experimental autoimmune myasthenia gravis

BackgroundThe thymus plays an essential role in the pathogenesis of myasthenia gravis (MG). In patients with MG, natural regulatory T cells (nTreg), a subpopulation of T cells that maintain tolerance to self-antigens, are severely impaired in the thymuses. In our previous study, upregulated nTreg cells were observed in the thymuses of rats in experimental autoimmune myasthenia gravis after treatment with exosomes derived from statin-modified dendritic cells (statin-Dex).MethodsWe evaluated the effects of exosomes on surface co-stimulation markers and Aire expression of different kinds of thymic stromal cells, including cTEC, mTEC, and tDCs, in EAMG rats. The isolated exosomes were examined by western blot and DLS. Immunofluorescence was used to track the exosomes in the thymus. Flow cytometry and western blot were used to analyze the expression of co-stimulatory molecules and Aire in vivo and in vitro.ResultsWe confirmed the effects of statin-Dex in inducing Foxp3+ nTreg cells and found that both statin-Dex and DMSO-Dex could upregulate CD40 but only statin-Dex increased Aire expression in thymic stromal cells in vivo. Furthermore, we found that the role of statin-Dex and DMSO-Dex in the induction of Foxp3+ nTreg cells was dependent on epithelial cells in vitro.ConclusionsWe demonstrated that statin-Dex increased expression of Aire in the thymus, which may further promote the Foxp3 expression in the thymus. These findings may provide a new strategy for the treatment of myasthenia gravis.

Virgin coconut oil enhances neuroprotective and anti‐inflammatory factors in the thymus and mesenteric lymph nodes of rats

AbstractObjectiveVirgin coconut oil (VCO) is used as a traditional medicine in Asian countries because of its therapeutic effects mediated through hypolipidemic, antimicrobial and anti‐oxidant properties. The interactions between the sympathetic noradrenergic nervous system and the immune cells of the lymphoid organs (thymus and lymph nodes) modulate immunity to determine health or onset of inflammatory diseases. The aim of the present study was to investigate the role of VCO in modulating neuronal and anti‐inflammatory factors in the thymus and mesenteric lymph nodes (MLN).MethodsYoung male Wistar rats (n = 8/group) were fed with a control diet or diet supplemented with 4%, 8%, and 16% of VCO. After a 30‐day treatment period, thymus and MLN were isolated to analyze the expressions of p‐tyrosine hydroxylase, nerve growth factor, p‐nuclear factor‐κB (p50 and p65), p‐mechanistic target of rapamycin, SIRT1, p‐LKB1 and intracellular signaling molecules (p‐ERK, p‐Akt, p‐CREB). Activities of anti‐oxidant enzymes and the extent of lipid peroxidation were also analyzed.ResultsIn the thymus, a VCO diet enhanced the expression of p‐tyrosine hydroxylase, nerve growth factor and SIRT1, and the activities of anti‐oxidant enzymes, whereas it decreased the expression of p‐nuclear factor‐κB (p50 and p65) and the extent of lipid peroxidation. In the MLN, VCO augmented the expression of p‐tyrosine hydroxylase, nerve growth factor, p‐mechanistic target of rapamycin, SIRT1 and p‐LKB1, and activities of anti‐oxidant enzymes, whereas p‐nuclear factor‐κB (p50 and p65) expression was inhibited. VCO enhanced the expression of intracellular signaling molecules in both the thymus and MLN.ConclusionDietary VCO might modulate immune responses by upregulating neuroprotective factors, and suppressing inflammatory mediators and oxidative stress through intracellular signaling pathways.

Preliminary study on tolerance induction by combined of rat thymus and metanephros anlages transplantation preconditioned with cyclophosphamide protocol

Objective To investigate whether allo-or xenotransplantation tolerance can be induced by transplanted thymus combined with metanephros primordia, from rats to cyclophosphamide (CP) pretreated recipients. Methods Two pairs of thymus and metanephros primordia were extracted from the Lewis rats on embryonic day16 (E16) and implanted into experiment (Ⅰ) group or control (Ⅱ, Ⅲ, Ⅳ) group renal capsules and omenta of thymectomized recipients, which had been pretreated with CP (80 mg/kg in BN rats and 200 mg/kg in C57BL/6 mice, ip, q6d×4). Post-transplantation, subcutaneous injection (sc, qd×12 d) of cyclosporine [8 mg/(kg·d) in BN rat and 12 mg/(kg·d) in C57BL/6 mouse] were simultaneously administrated till the 13th day. Histopathological examination of thymus and metanephros grafts and functional of developed metanephroi were performed post-transplantation. Rat seruminterleukin (IL)-2 and interferon-γ (IFN-γ) levels, one-way mixed lymphocyte reaction (MLR) and skin transplantation tests were measured. Results On the 14th day post-xenotransplantation, the thymus and metanephros primordia of Lewis rats were not found in the C57BL/6 mouse. On the 21st day after allotransplantation, the thymus and metanephros of some experimental (Ⅰ) group developed well, displaying partial urinary function. In experimental (Ⅰ) group, Banff rejection score (χ2=6.316, P 0.05) and SI had no significant difference (F=0.920, P>0.05). 5-7 weeks post-transplantation, acute rejection of metanephros and thymus deteriorated and connective tissue scars gradually formed. Conclusion Using the CP pretreatment protocol, E16 Lewis thymus and metanephros anlagens xenografted into C57BL/6 mice failed to grow and function, whereas fail to induce allogeneic immune tolerance but can grow and develop in the peritoneal cavity of BN rat, produce donor-specific immune hyporesponsiveness. Key words: Embryo; Thymus Primordia; Metanephros primordia; Transplantation; Tolerance

Gonadotropin-Releasing Hormone in Regulation of Thymic Development in Rats: Profile of Thymic Cytokines.

An increasing body of recent experimental data confirms the impact of neurohormones on fetal development and function of different body systems. The synthesis of many neurohormones starts in fetal tissues before the hypothalamic–pituitary–adrenal and hypothalamic–pituitary–gonadal systems are formed, and their high levels are detected in the bloodstream. Here, we studied the role of gonadotropin-releasing hormone (GnRH) in rat thymus development and tried to reveal possible mechanisms underlying the GnRH effects in early development. Western blotting and reverse transcription-polymerase chain reaction allowed us to identify receptor for GnRH in the fetal thymus with peak expression on embryonic days 17–18 (ED17–18). Blocking the receptors in utero on ED17 by a GnRH antagonist suppressed the concanavalin A-induced proliferative response of T cells in adults. GnRH (10−7 M) increased mRNA expression of interleukin (IL)-4, IL-10, IL-1β, interferon γ (IFNγ), and tumor necrosis factor α (TNFα) in the thymus of 18-day fetuses after an ex vivo culture for 24 h. The increased mRNA levels of the cytokines in the thymus were accompanied by increased numbers of CD4+ T helpers. Overall, the data obtained confirm the regulatory or morphogenetic effect of GnRH on fetal thymus development mediated by synthesis of thymic cytokines.

The Pungent and Hot Chinese Herbs Cause Heat Syndrome in Rats by Affecting the Regulatory T Cells.

Heat syndrome is a folk saying in China, which is used to describe people with symptoms such as aphtha, oral ulcer, glossitis, swelling and aching of gingiva, and dry eye. Aconitum carmichaelii Debx. (A), Zingiber officinale Rosc. (Z), and Cinnamomum cassia Presl (C) are the representatives of pungent and hot Chinese herbs which may cause heat syndrome. In order to explore the mechanism of pungent herbs-induced heat syndrome, rats were treated with AZC extracts at different concentrations and at different time periods. A series of cytokines were determined using the cytokine antibody array; some immunosuppressive cytokines, including TGF-β, IL-10, and IL-35, significantly increased in AZC group as compared with control group. Higher mRNA expressions of Foxp3, TGF-β, IL-10, and IL-35 were found in the spleen and thymus of rats after treatment for 18 days based on RT-PCR. Flow cytometry result revealed that the percentage of CD4+CD25+ Treg cells and Foxp3+CD4+CD25+ Treg cells in spleen lymphocytes showed an increasing trend from the 3rd day to the 18th day after treatment with middle dose of AZC extracts. It is speculated that extracts of AZC herbs may affect the development of heat syndrome by influencing Treg cells and immunosuppressive cytokines.

THE EFFECT OF THE COLD STRESS ON MORPHOLOGICAL AND FUNCTIONAL PARAMETERS OF THE THYMUS IN THE EXPERIMENT

The thymus is the central organ of the immunogenesis, the functioning of which determines the protective reactions of the organism. Various stressors can influence the immune organs. One of these factors is exposure to low temperatures. The aim of this research was studying the effect of experimental cold stress on the morphological and functional state of rat thymus using morphometric analysis. The cold exposure was done by placing the rats in individual cages in a refrigeration chamber at a temperature of -10 ± 20 °C for 1 hour at the same time of day for 7, 14, 21, and 30 days. Histological examination of thymus preparations stained with hematoxylin and eosin; on the 7th day after exposure to cold, the area of the cortical substance is significantly reduced compared with the control group, while the area of the medulla tends to increase. Analysis of the cell composition showed an increase in the number of epithelia-reticular cells in the subcapsular zone and a slight decrease in the number of lymphocytes. On the 14th day of exposure, the areas of cortical and medulla and the cortical-cerebral index do not differ from the indicators of intact control. Morphometric counting of cellular elements showed an increase in the number of lymphocytes, epithelia-reticulocytes, and macrophages. After 21 days of the experiment, data on the relative areas of cortical and medulla shows a significant decrease in the rate compared with all the first groups. The counting of cellular elements during this period showed marked changes observed in all morphological and functional zones of the thymus. In the subcapsular zone, there is a sharp decrease in the number of dividing lymphocytes. The number of epithelia-reticular cells is increased relative to the norm. There is frequent detection of apoptotic bodies and fat cells. In the medulla, there is an increase in the number of epithelia-reticulocytes compared with the 7th and 14th day. On the 30th day after exposure, the areas of cortical, medulla, and cortical-cerebral index remained at the same level as on the 21st day. There is a significant decrease in epithelia-reticular cells in the subcapsular zone, a significant decrease in the cortical substance and the cortico-medullary zone compared with all groups, and a significant increase in their number in the medulla. Hassall’s bodies are characterized by pronounced degenerative changes in epithelia-reticulocytes with cellular debris. In the subcapsular zone, a reduced number of cells with mitosis figures is maintained. It was established that as a result of cold stress on days 7, 21 and 30, there is a redistribution of volume and cellular composition, various structural and functional zones, indicating a decrease in the functional activity of the thymus, an increase in the death of lymphocytes by apoptosis, a decrease in mitotic activity, and accumulation of macrophages. Morphological and functional data of the 14th day of the experiment indicate the development of compensatory-adaptive changes in the thymus on the cold effect, manifested in the form of activation of cell division in the cortical substance and the cortical-medullary zone.

Effects of Aqueous Extract of Ocimum gratissimum Leaves and Vitamin C on Lead Acetate-induced Changes in the Thymus of Adult Wistar Rats

Lead is a heavy metal found in earth’s crust. It is a widespread and insidious environmental toxin known as a severe and aggressive contaminant to human and animal organisms’ health status. This work is aimed at evaluating the effect of aqueous extract of Ocimum gratissimum (OG) on lead induced changes in the thymus of adult albino wistar rats. Thirty five male Wistar rats were used in the study and were randomly divided into seven groups with five rats in each group. The rats in Group one (G1) served as the Control and received distilled water. Group 2 received 120 mg/kg body weight (bwt) of lead acetate, G3 received 375 mg/kg bwt of OG only. G4 received 120 mg/kg bwt of lead acetate and OG extract at 375 mg/kg bwt., G5 received 120 mg/kg bwt of lead and OG at 750 mg/kg bwt. G6 received 375 mg/kg bwt of OG in two weeks followed by 120 mg/kg bwt of lead acetate for one week, while G7 received 120 mg/kg bwt of lead acetate and Vitamin C at 11900 mg/kg. All the administrations were carried out orally for twenty one (21) days. At the end of the administration, the rats were fasted for 24 hours. They weighted and humanely sacrificed via cervical dislocation. The thymus were harvested in all the groups and prepared for histological studies using routine haematoxylin and eosin (H&E) staining techniques. The result of the present study shows that lead possessed a distortive effect in the histoarchitecture of thymus of the wistar rat in G2 when compared with G1. Treatment of these experimental animals with vitamin C prove to posses more ameliorative effect in restoring the histoarchitecture on lead toxicity in the thymus closed to normal than OG. Therefore, it is suggested that aqueous extract OG can act via the same pathway as vitamin C, in maintaining the normal histological structures of the thymus of adult albino wistar rat exposed to lead toxicity.

Cellular Composition of Rat Thymus with Combined Effects of Carcinogen and Stress

The aim of the research was study the effects of experimental breast cancer and stress on the thymus of laboratory animals Material and methods . Thymus 40 white nonlinear female rats of the same age were investigated using luminescent-histochemical, general histological and immunohistochemical methods . The animals were divided into 3 groups. In the 1st group were intact animals. Rats of the 2nd group were injected with N-methyl-N-nitrosourea, causing breast cancer. Animals of the 3rd group experienced a combined effect of carcinogen and water-immobilization stress. Results. It was established that the administration of N-methyl-N-nitrosourea to female rats causes an increase in the size of the medullar and cortex of the thymus lobes. In cells of the premedullary and subcapsular zones, an increase in the level of serotonin and catecholamines is observed, and in cells of the premedullary zone, in the thymocytes of the cortex and medulla - a decrease in the level of histamine. The ratio (serotonin + histamine) / catecholamines decreases and the percentage of degranulated mast cells increases. Also, the number of mature T-lymphocytes and macrophages is increasing against the background of a decrease in the number of S-100+ cells. Combined effect of factors revealed a decrease in the size of the lobes of the organ, the replacement of the parenchyma with adipose and connective tissue, an increase in the content of serotonin and catecholamines, a significant decrease in histamine levels, with a decrease in the ratio (serotonin + histamine) / catecholamines in the same cells, an increase in mature forms of T-lymphocytes and macrophages, as well as a decrease in the percentage of dendritic cells. Conclusion. The combined effect causes a more pronounced disorganization of the morphofunctional state of the thymus and leads to the 4th phase of the accidental involution of the thymus with the development of atrophy and sclerosis of the organ.

Morphological Changes in the Thymus of Newborn Rats Exposed to Endocrine Disruptor Dichlorodiphenyltrichloroethane (DDT) during the Prenatal Period.

The structure of the thymus in newborn rats exposed in utero to endocrine disruptor DDT was studied. We found that exposure to low doses of DDT during pregnancy does not disturb thymus formation in the offspring, but leads to changes in its structure than manifested as slower lobulation, wider epithelium-free areas in the cortex, and lower number of thymic corpuscles in the medulla. The results attest to sensitivity of the reticuloepithelial stroma of the thymus to the effects of endocrine disruptor.

Gender-Related Effect of Sodium Dichloroacetate on the Number of Hassall's Corpuscles and RNA NKCC1 Expression in Rat Thymus.

The aim was to investigate the effect of dichloroacetate (DCA) on thymus weight, Hassall's corpuscle number (HCs), and NKCC1 RNA expression in Wistar rats aged 4–5 weeks. They were investigated in the controls and DCA-treated gonad-intact and castrated males and females. The treatment lasted 4 weeks with DCA 200 mg/kg/day. At the end of the experiment, rat thymus was weighted, and its lobe was taken for the expression of NKCC1 RNA determined by the PCR method and of Hassall's corpuscles by immunohistochemistry. DCA caused a thymus weight decrease in DCA-treated gonad-intact rats of both genders as compared with their controls (p < 0.05), and no such impact was found in castrated DCA-treated males and females. DCA caused an increase of the HCs in gonad-intact males (p < 0.05), and no such increase in the DCA-treated gonad-intact females was found. There was gender-related difference in the HCs when comparing DCA-treated gonad-intact males and females: males showed significantly higher HCs (p < 0.05); no gender-related differences were found in the castrated DCA-treated groups. The Slc12a2 gene RNA expression level was found to be significantly decreased only in gonad-intact and in castrated DCA-treated males. The authors discuss the gender-related DCA effects on the thymus.