Development of broiler chickens after treatment with thymulin 5cH: a zoo technical approach.

Modulation of immune response due to thymulin 5cH has been previously observed. The aim of the present study is to evaluate the development of broiler chickens treated with thymulin 5cH by conventional zoo technical indices, phytohemaglutinin induced inflammation test and histomorphometric analysis of lymphoid organs (thymus, Fabricius bursa and spleen). Animals were divided in two groups: (a) test: birds with free access to thymulin 5cH diluted into the drink water and (b) control: birds with free access to water only, from the 1st to the 42nd day of life. All experimental procedures were done in blind. The results show that thymulin 5cH treated group had increased productivity index compared to control (391.45 versus 261.93) associated with higher viability in the 7th week (p = 0.013), and a possible shunt to B lymphocyte activity. The data suggest that thymulin 5cH could be a viable method to improve productivity in poultry production due to its immune modulation properties.

Neonatal thymulin gene therapy in nude mice: Effects on the morphology of the pituitary corticotrope population.

The integrity of the thymus during early life is necessary for a proper maturation of the neuroendocrine system, including the adrenal axis. The thymic metallopeptide thymulin seems to be a central physiologic mediator of thymus-pituitary communication. Furthermore, neonatal thymulin gene therapy has been shown to prevent the typical alterations of gonadotrophic cell number and morphology and serum gonadotropin levels in nude female mice. In the present study we assessed the impact of athymia and the effect of neonatal thymulin gene therapy on the corticotropic cell population in nude mice. The effect of thymulin administration to adult nudes on their hypothalamic content of corticotropin-releasing hormone (CRH) and the adrenal content of corticosterone was also determined. We used an adenoviral vector expressing a synthetic gene for the thymic peptide thymulin (metFTS) termed RAd-FTS. On postnatal day 1 or 2, heterozygous (nu/+) and homozygous (nu/nu) pups of both sexes received a single bilateral i.m. injection of RAd-FTS or RAd-GFP, a control vector. On postnatal day 71, mice were bled and sacrificed, and their pituitaries were immediately dissected, fixed and immunostained for corticotropin. Morphometry was performed by means of an image-analysis system. The following parameters were calculated: volume density (VD: Σ cell area/reference area), cell density (CD: number of cells/reference area), and cell surface (CS: expressed in µm²). Serum thymulin levels were measured by a bioassay, and CRH as well as corticosterone were determined by IRMA and RIA, respectively. Neonatal thymulin gene therapy in the athymic mice restored their serum thymulin levels and increased corticotrope CD, VD and CS in both control and athymic mice. Athymic mice showed only a marginal reduction in corticotrope CD, VD and CS. In these mutants hypothalamic CRH content was slightly increased, whereas adrenal corticosterone tended to be lower. Thymulin administration to adult mice tended to reverse these changes. Our results suggest a possible modulating effect of thymulin on the corticotrope population and the adrenal gland, confirming the existence of a bidirectional thymus-pituitary-adrenal axis.

Thymulin inhibits monocrotaline-induced pulmonary hypertension modulating interleukin-6 expression and suppressing p38 pathway.

The pathogenesis of pulmonary hypertension (PH) includes an inflammatory response. Thymulin, a zinc-dependent thymic hormone, has important immunobiological effects by inhibiting various proinflammatory cytokines and chemokines. We investigated morphological and hemodynamic effects of thymulin administration in a rat model of monocrotaline (MCT)-induced PH, as well as the pattern of proinflammatory cytokine gene expression and the intracellular pathways involved. Adult Wistar rats received an injection of MCT (60 mg/kg, sc) or an equal volume of saline. One day after, the animals randomly received during 3 wk an injection of saline, vehicle (zinc plus carboxymethyl cellulose), or thymulin (100 ng/kg, sc, daily). At d 23-25, the animals were anesthetized for hemodynamic recordings, whereas heart and lungs were collected for morphometric and molecular analysis. Thymulin prevented morphological, hemodynamic, and inflammatory cardiopulmonary profile characteristic of MCT-induced PH, whereas part of these effects were also observed in MCT-treated animals injected with the thymulin's vehicle containing zinc. The pulmonary thymulin effect was likely mediated through suppression of p38 pathway.

Thymulin evokes IL-6-C/EBPbeta regenerative repair and TNF-alpha silencing during endotoxin exposure in fetal lung explants.

Chorioamnionitis is associated with increased risks of perinatal respiratory failure; however, components of the inflammatory acute-phase response are known to actively promote lung maturation. To manipulate this relationship, we examined the effect of the thymic immunomodulator thymulin on fetal lung mesenchyme-epithelial differentiation during exposure to Escherichia coli lipopolysaccharide (LPS). Gestation day 14 fetal rat lung explants were cultured for 96 h at fetal (23 mmHg) or ambient (142 mmHg) Po(2). Airway surface complexity (ASC, perimeter/ radical area(2)) was greater at fetal vs. ambient Po(2); however, exposure to 0.1-50 microg/ml LPS significantly raised ASC at 2 microg/ml in ambient Po(2) explants. LPS (50 microg/ml) depressed ASC in both conditions to untreated ambient Po(2) control values without changes in necrosis or apoptosis. To manipulate LPS-evoked TNF-alpha and IL-6 release, we exposed explants and A549 cells to combinations of 50 microg/ml LPS, 10 microM ZnCl(2), and 0.1-1,000 ng/ml thymulin at either Po(2). Thymulin+Zn(2+) suppressed and potentiated LPS-evoked TNF-alpha and IL-6 release, yielding an IC(50(TNF-alpha)) of 0.5 +/- 0.01 ng/ml and EC(50(IL-6)) of 1.4 +/- 0.3 ng/ml in A549 cells. This was accompanied by activation of the p38 MAPKMAPKAP-K2 pathway with sustained expression of TNF-alpha and IL-6 transcripts at ambient Po(2). LPS+thymulin+Zn(2+)-treated explants showed proliferation of CCAAT-enhancer binding protein-beta (C/EBPbeta) and fibroblast growth factor-9 immunoreactive mesenchyme, which was abolished by IL-6 antisense oligonucleotides. The posttranscriptional suppression of immunogenic TNF-alpha synthesis coupled with raised IL-6 and C/EBPbeta-dependent mesenchyme proliferation suggests a role for bioactive thymulin in regulating regenerative repair in the fetal lung.

Immunopotentiation of a developed Salmonella enterica serotype enteritidis vaccine by thymulin and zinc in meat chicken breeders.

The humoral immunity, spleen and thymus weight indices, lymphocyte count in the thymus cortex, and granuloma diameter at vaccination sites were assessed in four differently immunopotentiated groups of meat chicken breeders. Breeders in the first two groups were given a killed Salmonella enterica serotype Enteritidis (SE) vaccine subcutaneously at 15 and 19 weeks of age. Breeders in the third and fourth groups were left unvaccinated. Breeders in the first group were further immunopotentiated with zinc and thymulin. Each bird in the first group was given the immunopotentiators intraperitoneally in a volume of 0.1 ml at intervals of 3 days for a period of 3 weeks, starting at 15 weeks of age. At each time, each bird in the first group received thymulin (10 ng) and ZnCl2 (1 micromol/L), using a carboxymethyl cellulose carrier, totalling 90 ng thymulin and 9 micromol of ZnCl2 per bird. Each bird in the first three groups was challenged orally with 6.7 x 10(6) cfu/ml of highly virulent SE organisms, at an age of 22 weeks. The first group, which had received zinc and thymulin, had the earliest and highest humoral immune response to SE (p<0.05). This was observed at 2 and 4 weeks after the first vaccination. In addition, the first group had the highest mean thymus weight index, and the highest mean lymphocyte count in the thymus cortex. No significant difference was observed between the first two vaccinated groups in the mean granuloma diameter developed at the two vaccination sites 48 h after administration of the vaccine (p>0.05).

FTS reduces bleomycin-induced cytokine and chemokine production and inhibits pulmonary fibrosis in mice.

Bleomycin (BLM), an antitumour drug, is known to cause interstitial pneumonia followed by pulmonary fibrosis, and has often been used to produce an animal model of pulmonary fibrosis. In the present study, we examined the effect of a nonapeptide thymic hormone, facteur thymique serique (FTS), on the murine lung fibrosis induced by intratracheal instillation of BLM. Treatment with FTS ameliorated BLM-induced fibrotic changes in a dose-dependent manner, as indicated by the reduced accumulation of hydroxyproline (HP). In addition, FTS suppressed BLM-induced cellular inflammatory response in the lungs, as evidenced by inhibition of increased lung weight, reduced accumulation of inflammatory leucocytes, including lymphocytes and neutrophils, but not macrophages, and less pronounced histopathological changes. Finally, BLM challenge increased the local synthesis of proinflammatory cytokines, TNF-alpha and IL-1beta and chemokines, MCP-1, MIP-1alpha RANTES, MIP-2 and KC, while administration of FTS suppressed the production of these cytokines, except for MCP-1. These effects of FTS were observed only when mice received intratracheal instillation with BLM. Considered collectively, our results indicated that FTS treatment ameliorated the cellular inflammatory responses and fibrotic changes in the lungs caused by BLM and such inhibition was well correlated with reduced synthesis of several fibrosis-related cytokines, and suggested that FTS may be potentially useful for the treatment of pulmonary fibrosis.

Immunomodulatory potential of thymulin-Zn(2+) in the alveolar epithelium: amelioration of endotoxin-induced cytokine release and partial amplification of a cytoprotective IL-10-sensitive pathway.

The immunomodulatory potential of thymulin in the perinatal epithelium is not well characterized. In an in vitro model of fetal alveolar type II epithelial cells, we investigated the exhibition of an anti-inflammatory activity of this peptide hormone. Thymulin selectively ameliorated, in a dose-dependent manner, the endotoxin-induced release of IL-1 beta (IC(50) = 657 ng. ml(-1)), but showed no inhibitory effect on IL-6 and TNF-alpha. Zinc, an anti-inflammatory antioxidant, which is required for the biological activity of thymulin, reduced the secretion of IL-1 beta (IC(50) = 62 microM), TNF-alpha (IC(50) = 1000 microM), and, to a lesser extent, IL-6. This cation (100 microM) amplified the effect of thymulin on IL-1 beta and TNF-alpha (IC(50) < 0.1 ng. ml(-1)), but not on IL-6. Analysis of whether thymulin is up-regulating a counterpart anti-inflammatory signaling loop revealed the involvement of an IL-10-sensitive pathway. These results indicate that thymulin acts as a novel dual immunoregulator by enhancing an anti-inflammatory cytoprotective response and depressing an inflammatory signal, an effect synergistically amplified, in part, by cationic zinc.

The effect of "facteur thymique serique" (FTS) on catecholamine and serotonin neurotransmission in discrete brain regions of mice.

The dose-related effect of Facteur Thymique Serique (FTS) on hypothalamic, mesencephalic and striatal neurotransmission were investigated after intracerebroventricular (icv) administration. FTS pretreatment with dose of 1 microgram (icv) increased the mesencephalic serotonin content, while failed to influence the hypothalamic and striatal serotonin levels. The nonapeptide in a dose of 0.1 microgram (icv) decreased the hypothalamic, while in a dose of 1 microgram the hypothalamic and also the mesencephalic dopamine content, but did not influence the striatal dopamine level. FTS in a dose of 1 microgram (icv) significantly decreased the hypothalamic noradrenaline level, but did not influence the noradrenaline content of the mesencephalon and striatum. These results suggest that FTS is able to modify central neurotransmission.

Studies on mouse auto-reactive cells. II. Cytotoxicity exerted by mouse lymphocytes against syngeneic erythrocytes.

In mice, an in vitro cell-mediated cytotoxicity is directed towards syngeneic erythrocytes used as targets. This phenomenon occurs in lymphoid organs of normal, non-immunized mice. Its intensity is greater in the thymus than in spleen or lymph nodes. The study of the nature of the cell responsible for this spontaneous syngeneic cytotoxicity ruled out the role of macrophages. The involvement of T cells in this phenomenon is assessed by its disappearance after the lymphoid cells had been treated with anti-theta serum plus complement, by its disappearance from lymphoid organs of mice previously treated by hydrocortisone, and by its decrease in the presence of synthetic thymic factor. Moreover, spontaneous syngeneic cytotoxicity is lost when lymphoid cells are depleted at autologous rosettes by centrifugation on a Ficoll-Hypaque gradient after rosette formation. Cytotoxic lymphocytes might belong to the population of auto-rosettes previously characterized as a population of immature T cells.