epidermal-growth-factor and Abnormalities--Drug-Induced

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant that produces adverse biological effects including developmental toxicity and teratogenesis. In the mouse embryo, TCDD induces cleft palate and hydronephrosis. The synthetic glucocorticoid, hydrocortisone (HC), induces cleft palate and a potent, synergistic interaction has been observed between TCDD and HC in C57BL/6N embryonic mice. The morphology and etiology of TCDD- and HC-induced clefts are distinctly different with formation of small palatal shelves following HC exposure and failure of normally-sized shelves to fuse after TCDD treatment. Each exposure also alters expression of several growth factors. When EGF, TGF alpha, EGF receptor, and the TGF beta's are considered as a combinatorial, interacting set of regulators, TCDD and HC each produce a unique pattern of increased and/or decreased expression across the set. The interaction of HC and TCDD results in a cleft palate whose etiology most closely resembles that observed after HC exposure, i.e. small palatal shelves. HC+TCDD-exposure also produces a pattern of growth factor expression which closely resembles that seen after HC. Both TCDD and HC act through receptor-mediated mechanisms and each compound has its own receptor. The Ah receptor (AhR) binds TCDD and the glucocorticoid receptor (GR) binds HC. On gestation day (GD) 14, in the embryonic palate exposed to TCDD, the AhR was downregulated and the GR expression increased. Conversely, following HC exposure, the GR was downregulated and AhR levels were elevated. HC+TCDD produced increased expression of both receptors and this pattern would be predicted to produce HC-like clefts as the GR-mediated responses would result in small palatal shelves. The observed cross-regulation of the receptors is believed to be important in the synergistic interaction between TCDD and HC for the induction of cleft palate.

Topics: Abnormalities, Drug-Induced; Animals; Cleft Palate; Drug Interactions; Drug Synergism; Epidermal Growth Factor; Female; Glucocorticoids; Mice; Mice, Inbred C57BL; Palate; Polychlorinated Dibenzodioxins; Pregnancy; Receptors, Aryl Hydrocarbon; Receptors, Glucocorticoid; Transforming Growth Factors

The aim of this study was to evaluate the effect of the traditional Chinese medicine tetrandrine (Tet) and to determine its possible mechanism on expression of endothelin-1 (ET-1) and epidermal growth factor (EGF) in the lung of a rat model of nitrofen-induced congenital diaphragmatic hernia (CDH).. A single oral dose (115 mg/kg) of nitrofen on day 9.5 of pregnancy was maternally administered to induce CDH. Pregnant rats were divided into 4 groups on day 18.5: control (n = 5), CDH (n = 5), CDH+dexamethasone (Dex) (n = 5), and CDH+Tet (n = 5). All fetuses were delivered by cesarean delivery on day 21.5. Accordingly, there were 4 groups of fetuses: control (n = 38), CDH (n = 25), CDH+Dex (n = 21), and CDH+Tet (n = 22). Lung tissue weight (LW) and body weight (BW) of each fetus were recorded, lung histologic evaluations and ET-1 and EGF immunohistochemistry staining were performed, and image analysis was performed after lung processing.. Five female rats in the control group produced 38 fetuses without CDH. CDH was observed in 68 of the 128 rat fetuses (53.1%) among the other 3 groups. The LW/BW ratio of the CDH group was significantly lower than those of the Dex and EGF groups (P < .05). The lungs of fetuses with CDH showed marked abnormal structure such as pulmonary hypoplasia and vascular remodeling, in contrast to improved pulmonary structure in lungs of fetuses in the CDH+Dex and CDH+Tet groups. Statistical differences in morphologic parameters (radial alveolar counts, percentage of alveoli, percentage of medial wall thickness, and vascular volume) were found (P < .05). The immunoreactivity of EGF and ET-1 in the CDH group was markedly stronger than that in the control, CDH+Dex, and CDH+Tet groups (P < .01). In addition, EGF and ET-1 expression in the CDH+Dex and CDH+Tet groups was stronger than that in the control group (P < .05). There was no difference in lung EGF and ET-1 immunoreactivity between CDH+Dex and CDH+Tet groups (P > .05).. Antenatal treatment with Tet may improve lung growth and vascular remodeling, and its mechanism seems to be involved in decreasing EGF and ET-1 expression. Tet administered maternally may be a hopeful new therapeutic option in the treatment of CDH and may be effective in helping to avoid the side effects of Dex.

Topics: Abnormalities, Drug-Induced; Alkaloids; Animals; Benzylisoquinolines; Birth Weight; Dexamethasone; Drug Evaluation, Preclinical; Drugs, Chinese Herbal; Endothelin-1; Epidermal Growth Factor; Female; Fetal Organ Maturity; Hernia, Diaphragmatic; Lung; Organ Size; Phenyl Ethers; Pregnancy; Pulmonary Artery; Random Allocation; Rats; Rats, Sprague-Dawley

Epidermal growth factor (EGF) and transforming growth factor-alpha (TGFalpha) regulate cell proliferation and differentiation in the embryo. The induction of cleft palate (CP) by all trans-retinoic acid (RA) was associated with altered expression of TGFalpha, EGF receptor, and binding of EGF. This study uses knockout (KO) mice to examine the roles of EGF and TGFalpha in teratogenic responses of embryos exposed to RA.. Pregnant wild-type (WT) mice of mixed genetic background, EGF KO, C57BL/6J, and TGFalpha KO mice were given a single oral dose of RA (100 mg/kg, 10 ml/kg) or corn oil on GD 10 at 12 PM, GD 11 at 12 PM or 4 PM, or GD 12 at 8 AM or 12 PM (plug day = GD 0). GD 18 fetuses were examined for external, visceral, and skeletal effects.. After exposure to RA on GD 12, the incidence of CP in EGF KO was significantly reduced relative to WT. In TGFalpha KO fetuses, RA exposure on GD 10 increased the incidence of CP versus C57BL/6J. The incidence of skeletal defects in the limbs, vertebrae, sternebrae, and ribs were also affected by lack of expression of EGF or TGFalpha with region-specific amelioration or exacerbation of the effects of RA. In TGFalpha KO fetuses, incidences of forelimb long bone and digit defects increased relative to C57BL/6J. In EGF KO fetuses, relative to WT, the incidence of hindlimb oligodactyly was increased. In EGF KO, but not WT, RA produced short, bent radius, humerus, and ulna. Both TGFalpha and EGF KO mice had increased incidences of dilation of the renal pelvis and this was reduced by RA.. RA exposure produced skeletal and visceral defects in all genotypes; however, EGF or TGFalpha KO influenced the incidence and severity of defects. This study supports a role for EGF and TGFalpha in the response to RA.

Topics: Abnormalities, Drug-Induced; Animals; Bone and Bones; Cleft Palate; Epidermal Growth Factor; Female; Fetus; Kidney Pelvis; Mice; Mice, Knockout; Phenotype; Pregnancy; Prenatal Injuries; Transforming Growth Factor alpha; Tretinoin

The environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate (CP) and hydronephrosis (HN) in mice. The etiology of these defects involves hyperproliferation of epithelial cells of the secondary palatal shelf and ureter, respectively. These effects correlate with altered expression of the epidermal growth factor receptor (EGFR), epidermal growth factor (EGF), and transforming growth factor-alpha (TGF-alpha). In this study, the developmental toxicity of TCDD was examined in EGF, TGF-alpha, and double EGF + TGF-alpha knockout (-/-) and wild type (WT) mice. The influence of background genetics in responsiveness to TCDD was examined using liver 7-ethoxyresorufin-O-deethylase (EROD) activity. Animals were dosed by gavage with 0, 0.2, 1, 5, 24, 50, 100, or 150 micro g TCDD/kg (5 ml/kg) body weight on gestation day 12. The mixed genetic background of WT, EGF (-/-), and EGF + TGF-alpha (-/-) made these mice less responsive to TCDD relative to C57BL/6J and TGF-alpha (-/-), which have a C57BL background. These results show that EGF and TGF-alpha are not required for response to TCDD; however, the specific ligand available to bind EGFR affects the responsiveness to TCDD. EGF (-/-) mice are less responsive for CP, but more sensitive to HN. TGF-alpha (-/-) mice were similar to WT in sensitivity for induction of CP and HN. The responses of EGF + TGF-alpha (-/-) mice were like the WT except at higher doses where sensitivity to CP increased, suggesting that the responses may be mediated by alternative ligands for EGFR that are not functional equivalents of EGF or TGF-alpha. In conclusion, the EGFR pathway is mechanistically important in responses of the embryo to TCDD. Specific ligands confer sensitivity or resistance that are target tissue-dependent.

Topics: Abnormalities, Drug-Induced; Administration, Oral; Animals; Cleft Palate; Cytochrome P-450 CYP1A1; Dose-Response Relationship, Drug; Environmental Pollutants; Epidermal Growth Factor; Female; Genetic Predisposition to Disease; Hydronephrosis; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microsomes, Liver; Polychlorinated Dibenzodioxins; Pregnancy; Teratogens; Transforming Growth Factor alpha

To investigate the morphologic changes of embryonic palatal development exposed to retinoic acid (RA) in mouse, and to detect the significance of the expression of TGFbeta1, TGFbeta3, EGF and BCL2.. The stage of palatal development was examined by light microscopy. S-P immunohistochemistry and in-situ hybridization was used to detect spatio-temporal patterns of expression of TGFbeta1, TGFbeta3, EGF and BCL2 in embryonic palate.. The fetus exposed to RA resulted in formation of small palatal shelves without contact and fusion of each other to form and intact palate. RA can regulate the embryonic palatal expression of genes involved in RA-induced cleft palate.. RA can inhibit the proliferation of MEPM cell to form small palatal shelves and induce abnormal differentiation of MEE cell causing the bi-palatal shelves no contact and fuse with each other, then induce the formation of cleft palate. RA can regulate the spatio-temporal patterns of expression of TGFbeta1, TGFbeta3 and EGF in embryonic palatal processes and the change of special expression of these genes in embryonic palatal processes are involved in RA-induced cleft palate.

Topics: Abnormalities, Drug-Induced; Animals; Cleft Palate; Embryo, Mammalian; Epidermal Growth Factor; Female; Mice; Mice, Inbred C57BL; Palate; Transforming Growth Factor beta; Tretinoin

In utero, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure causes abnormal ventral, dorsolateral, and anterior prostate development in C57BL/6J mice. Androgens, mesenchymal-epithelial interactions, and growth factor expression all have roles in initiating and regulating development and growth of the prostate. Epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha), both of which bind the EGF receptor (EGFR), are expressed in human and rodent developing prostate. This study examines the influence of null expression of EGF and/or TGF-alpha on prostatic bud development and on the ability of TCDD to inhibit prostatic budding. Growth factor knockout (-/-) and wild-type (WT) mice were exposed either to vehicle or to TCDD (0, 0.2, 1, 5, 10, 50, 100, or 150 microg/kg) on gestation day (GD) 12. The number of anterior, dorsal, and lateral prostatic buds (ADLB) and ventral buds (VB) were counted on GD 17.5. Control WT and EGF (-/-) fetuses had similar numbers of ADLB and VB. In control TGF-alpha (-/-) fetuses, the number of ADLBs was higher relative to the C57BL/6J. Control EGF + TGF-alpha (-/-) had poor bud outgrowth, especially in the ADL region. TCDD induced a dose-related decrease in bud formation in all strains with the formation of VBs being more sensitive than ADLBs. The severity of the response depended on growth factor expression, with the most severe effects on VBs in the EGF (-/-) and on ADLBs in the EGF + TGF-alpha (-/-) fetuses. TGF-alpha (-/-) and C57BL/6J fetuses responded to TCDD similarly. In conclusion, EGF and TGF-alpha expression are important for the formation of ADLBs and VBs, and expression of EGF and TGF-alpha affects the ability of TCDD to inhibit prostatic bud formation in a region-specific manner.

Topics: Abnormalities, Drug-Induced; Administration, Oral; Animals; Dose-Response Relationship, Drug; Epidermal Growth Factor; Epithelium; Female; Gene Expression Regulation, Developmental; Genetic Predisposition to Disease; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Microscopy, Electron, Scanning; Polychlorinated Dibenzodioxins; Pregnancy; Prostate; Teratogens; Transforming Growth Factor alpha

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), produces hydronephrosis by altering the differentiation and proliferation of ureteric epithelial cells in the fetal C57BL/6N mouse urinary tract. This study tests the hypothesis that the late fetal urinary tract epithelial cells respond to TCDD with increased proliferation and that the responses do not require contributions from other maternal or fetal tissues. This was achieved by exposing late gestation fetal urinary tract cells to TCDD in an in vitro model. Isolated ureteric cells from gestation day (GD) 18 fetal ureters were plated in medium supplemented with trace elements, a complex mixture of lipids, a defined mixture of purified hormones and growth factors. Both epithelial and mesenchymal cells remain viable under these conditions. The cultures were exposed to 0.1% dimethylsulfoxide (DMSO), 1x10(-8), 1x10(-9) or 1x10(-10) M TCDD. Exposure to 1x10(-10) M TCDD did not affect the cultures, while 1x10(-8) and 1x10(-9) M TCDD supported epithelial, but not mesenchymal, cell survival and stimulated epithelial cell proliferation and differentiation. The TCDD-exposed cells expressed high levels of keratin and little or no vimentin, confirming that the cells, which survive and differentiate are epithelial. However, after continuous exposure to epidermal growth factor (EGF), the TCDD-induced stimulation of ureteric epithelial growth could not be detected. In conclusion, this study demonstrates that late gestational ureteric cells respond to TCDD in vitro with the stimulation of epithelial cell growth and differentiation.

Topics: Abnormalities, Drug-Induced; Animals; Bromodeoxyuridine; Cell Differentiation; Cell Division; Epidermal Growth Factor; Epithelial Cells; Female; Immunohistochemistry; Male; Mice; Mice, Inbred C57BL; Polychlorinated Dibenzodioxins; Pregnancy; Teratogens; Urinary Tract

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exposure produces hydronephrosis and cleft palate in mice. These responses are correlated with disruption of expression of epidermal growth factor (EGF) receptor ligands, primarily EGF and transforming growth factor-alpha (TGF-alpha), and altered epithelial cell proliferation and differentiation. This research examined the role of these growth factors in TCDD-induced teratogenicity by using wild type (WT) and knockout (-/-) mice that do not express EGF, TGF-alpha, or both EGF and TGF-alpha. Pregnant females were weighed on GD 12 and dosed by gavage with either corn oil or TCDD at 24 microg/kg, 5 ml/kg. On GD 17.5, the maternal parameters evaluated included body weight, body weight gain, liver weight (absolute and adjusted for body weight). The number of implantations, live and dead fetuses, early or late resorptions, the proportion of males, fetal body weight, fetal absolute and relative liver weight, placenta weight, incidence of cleft palate, and the severity and incidence of hydronephrosis were recorded. TCDD did not affect maternal weight gain, fetal weight, or survival, but maternal and fetal liver weights and liver-to-body weight ratios were increased in all genotypes. The WT and TGF-alpha (-/-), but not the EGF (-/-) and EGF + TGF-alpha (-/-) fetuses, developed cleft palate after exposure to 24 microg TCDD/kg. Hydronephrosis was induced by TCDD in all genotypes, with the incidence in EGF + TGF-alpha (-/-) fetuses comparable to that of the WT. The incidence and severity of this defect was substantially increased in EGF (-/-) and TGF-alpha (-/-). In conclusion, this study demonstrated that expression of EGF influences the induction of cleft palate by TCDD. Also, EGF and TGF-alpha are not required for the induction of hydronephrosis, but when either is absent the response of the fetal urinary tract to TCDD is enhanced.

Topics: Abnormalities, Drug-Induced; Administration, Oral; Animals; Body Weight; Cleft Palate; Environmental Pollutants; Epidermal Growth Factor; Female; Hydronephrosis; Liver; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Organ Size; Polychlorinated Dibenzodioxins; Pregnancy; Reproduction; Teratogens; Toxicity Tests; Transforming Growth Factor alpha

(1) To determine the ability of epidermal growth factor (EGF) to reverse antiandrogen-induced cryptorchidism and epididymal abnormalities; (2) to evaluate whether alterations in maternal EGF would result in abnormal testicular descent or mal development of the epididymis.. Experiment 1: Timed pregnant ICR mice were treated with either flutamide, flutamide plus EGF, or vehicle alone on gestational days 11 through birth. Experiment 2: Maternal EGF was abolished by removing the submandibular glands. Following timed mating, dams were treated with either flutamide, anti-EGF, DHT, or vehicle alone on gestational days 11 through birth.. Experiment 1: Treatment with flutamide resulted in a 36 percent (26/72) incidence of undescended testes (UDT), and a 43 percent (31/72) incidence of abnormal epididymides. Rats treated simultaneously with flutamide plus EGF had a reduced incidence of UDT (14%, 6/42) and epididymal anomalies (19%, 8/42); p < 0.01. Experiment 2: The absence of maternal EGF resulted in a significant incidence of cryptorchidism in 11/50 (22%) testes, and epididymal anomalies in 19/50 (38%); p < 0.01.. Our findings suggest that EGF stabilizes the wolffian duct system and partially mediates testicular descent.

Topics: Abnormalities, Drug-Induced; Animals; Cryptorchidism; Epidermal Growth Factor; Epididymis; Female; Flutamide; Male; Mice; Mice, Inbred ICR; Pregnancy; Testis

Epidermal growth factor, an androgen responsive paracrine factor, administered to pregnant mice has been reported to result in persistent wolffian ducts in female offspring. This fact led us to investigate whether epidermal growth factor can reverse the undescended testes and epididymal abnormalities associated with time specific flutamide administration. Timed pregnant Sprague-Dawley rats were treated with flutamide (undescended testes 74% and epididymal anomalies 53%) or flutamide plus epidermal growth factor (undescended testes 24% and epididymal anomalies 9%). The decrease in undescended testes and epididymal abnormalities following epidermal growth factor treatment was significant at p < 0.01. We performed immunohistological studies to evaluate whether flutamide alters epidermal growth factor expression in the paratesticular tissues during the time of maximal androgenic activity. These investigations revealed that antiandrogens did not alter epidermal growth factor expression in the fetal testes or epididymides. This finding suggests that epidermal growth factor does not reverse epididymal abnormalities or undescended testes by direct stimulation of the wolffian ducts or fetal testis.

Topics: Abnormalities, Drug-Induced; Animals; Cryptorchidism; Epidermal Growth Factor; Epididymis; Female; Flutamide; Immunohistochemistry; Male; Pregnancy; Rats; Testis

Retinoic acid (RA) is teratogenic in many species, producing multiple malformations, including cleft palate. The effects of RA which lead to cleft palate vary depending on the stage of development exposed. After exposure of embryonic mice to RA on gestation day (GD) 10, abnormally small palatal shelves form. After exposure on GD 12 shelves of normal size form, but fail to fuse, as the medial cells proliferate and differentiate into a nasal-like epithelium. Growth factors and their receptors play an important role in regulating development, and the expression of EGF receptors, EGF, TGF-alpha, TFG-beta 1, and TGF-beta 2 has been reported in the mouse embryo. In a variety of cell types in culture, these growth factors are capable of regulating proliferation, differentiation, expression of matrix proteins, and other cellular events including epithelial-mesenchymal transformations. The present study examines immunohistochemically the expression of EGF, TGF-alpha, TGF-beta 1, and TGF-beta 2 in the control embryonic palatal shelves from GD 12 to 15 and the effects of RA treatment on GD 10 or 12 on their expression on GD 14 and 16. These growth factors were shown to have specific temporal and spatial expression in the palatal shelf. With advancing development the levels of TGF-alpha decreased while the expression of EGF increased. TGF-beta 2 localization became regional by GD 14-15, with higher levels found in epithelial cells and chondrogenic mesenchyme. TGF-beta 1 occurred in epithelial and mesenchymal cells and distribution did not change substantially with advancing development. RA exposure altered the expression of TFG-alpha, TGF-beta 1, and TGF-beta 2, but significant effects on EGF were not found. The effects on TGF-alpha and TGF-beta 1 expression were dependent on the gestational age exposed. Levels of TGF-alpha on GD 14 decreased after RA exposure on GD 10, but increased after GD 12 exposure. TGF-beta 1 expression in the mesenchyme was increased after exposure on GD 12, but was unaffected by RA on GD 10. After exposure on either day, the levels of TGF-beta 2 increased in GD 14 nasal epithelial cells. Acting in concert, growth factors could regulate events critical to formation of the secondary palate, including cessation of medial epithelial cell proliferation, synthesis of extracellular matrix proteins in the mesenchyme, programmed cell death of medial epithelial peridermal cells, and transformation of basal epithelial medial cells to mesenchymal cells.

Topics: Abnormalities, Drug-Induced; Animals; Cell Differentiation; Cleft Palate; Epidermal Growth Factor; Female; Gene Expression Regulation; Male; Mice; Mice, Inbred C57BL; Morphogenesis; Palate; Pregnancy; Transforming Growth Factors; Tretinoin

Epidermal growth factor (EGF) injected into pregnant mice increased the frequency of cleft palate (CP) in cortisone-treated mouse fetuses. EGF alone produced proliferation and thickening of the epithelium of the palatal processes, but CP was not significantly increased over saline injected controls. Cortisone alone produced thinning of the palatal epithelium and caused CP in 61 percent of formed fetuses. The combination of EGF and cortisone treatment induced CP in 100 percent of formed fetuses; epithelial thickening still occurred with the combination treatment. Thus, EGF may be teratogenic under special circumstances. These observations suggest that the relative thickness of the palatal shelf epithelium may not be a critical factor in the fusion of the palatal shelves.

Topics: Abnormalities, Drug-Induced; Animals; Cleft Palate; Cortisone; Drug Synergism; Epidermal Growth Factor; Female; Mice; Palate; Peptides; Pregnancy; Teratogens