RESUMEN
We examined whether prenatal psychological stress with little physical stress causes changes in the behavior and neurogenesis of the offspring of Sprague-Dawley rats at one month. Dams in the last trimester of gestation were psychologically stressed by placing them in a social communication box and shocking a rat on the other side of a transparent wall. They suffered little physical stress. Male and female offspring from the dams showed little change in an open field test at postnatal day (PND) 30. To evaluate neurogenesis in the brain, BrdU was intraperitoneally injected at PND 35 into offspring not used in the open field test. Immunohistochemical examinations of BrdU in their dorsal hippocampus at PNDs 42 and 112 revealed that the number of BrdU immunopositive cells in the offspring of prenatally stressed rats was significantly smaller than in the offspring of unstressed ones. These results together with our previous finding that prenatal psychological stress can alter specific behaviors suggest that prenatal psychological stress can suppress neurogenesis in the dorsal hippocampus of rats of both sexes at PND 35 even though impairment in the behavioral task has not yet appeared.
Asunto(s)
Bromodesoxiuridina/metabolismo , Hipocampo/metabolismo , Actividad Motora/fisiología , Estrés Psicológico/fisiopatología , Animales , Animales Recién Nacidos , Conducta Animal/fisiología , Recuento de Células , Electrochoque/efectos adversos , Femenino , Hipocampo/citología , Inmunohistoquímica , Masculino , Neurogénesis/fisiología , Neuronas/citología , Neuronas/metabolismo , Embarazo , Efectos Tardíos de la Exposición Prenatal , Ratas , Ratas Sprague-Dawley , Estrés Psicológico/psicologíaRESUMEN
In humans, stressful events during pregnancy may raise the risk of psychiatric disorders in offspring, and studies with rodents have found that physical prenatal stress can cause changes in the physiology, neurobiology, and behavior of offspring. In the present study, we examined whether psychological prenatal stress with little physical stress could cause changes in the neurobiology and behavior of offspring in Sprague-Dawley rats, as physical prenatal stress did. Dams received psychological stress by observing a rat being electrically shocked behind a transparent wall in the social communication box during the last trimester of gestation but were not exposed to any physical stress. Male offspring from the dams exposed to psychological stress showed enhanced emotionality in an open field test, depression-like behavior in a forced swim test, and enhanced activity in the hypothalamo-pituitary-adrenal axis, compared with rats from untreated dams. However, the prenatally stressed rats showed intact ability to acquire context conditioning. This is the first report that psychological prenatal stress in the communication box can cause changes in the neurobiology and behavior of offspring in rodents.
Asunto(s)
Síntomas Afectivos/fisiopatología , Trastorno Depresivo/fisiopatología , Sistema Hipotálamo-Hipofisario/fisiopatología , Sistema Hipófiso-Suprarrenal/fisiopatología , Efectos Tardíos de la Exposición Prenatal/fisiopatología , Estrés Psicológico/fisiopatología , Síntomas Afectivos/etiología , Animales , Animales Recién Nacidos , Ansiedad/sangre , Ansiedad/fisiopatología , Ansiedad/psicología , Biomarcadores/metabolismo , Peso Corporal/fisiología , Condicionamiento Psicológico/fisiología , Hormona Liberadora de Corticotropina/metabolismo , Cortisona/sangre , Cortisona/metabolismo , Trastorno Depresivo/etiología , Estimulación Eléctrica/efectos adversos , Femenino , Sistema Hipotálamo-Hipofisario/metabolismo , Masculino , Núcleo Hipotalámico Paraventricular/metabolismo , Núcleo Hipotalámico Paraventricular/fisiopatología , Sistema Hipófiso-Suprarrenal/metabolismo , Embarazo , Efectos Tardíos de la Exposición Prenatal/sangre , Efectos Tardíos de la Exposición Prenatal/psicología , Proteínas Proto-Oncogénicas c-fos/metabolismo , Ratas , Ratas Sprague-Dawley , Estrés Psicológico/sangre , Estrés Psicológico/psicología , Natación/psicologíaRESUMEN
The ability of the complete genome sequence of enterohemorrhagic Escherichia coli O157 led to the identification of a 17-kb chromosomal region which contained a type III secretion system gene cluster at min 64.5. This locus contains open reading frames whose amino acid sequences show high degrees of similarity with those of proteins that make up the type III secretion apparatus, which is encoded by the inv-spa-prg locus on a Salmonella SPI-1 pathogenicity island. This locus was designated ETT2 (E. coli type III secretion 2) and consisted of the epr, epa, and eiv genes. ETT2 was found in enteropathogenic E. coli strains and also in some non-O157 Shiga toxin-producing E. coli (STEC) strains, but most of them contained a truncated portion of ETT2. Most O157 isolates had a complete collection of toxin-encoding genes eae and hlyA and the ETT2 locus, while most O26 strains had toxin-encoding genes eae and hlyA genes but an incomplete ETT2 locus. Thus, an intact copy of ETT2 might mark a pathogenic distinction for particular STEC strains. Therefore, the presence of the ETT2 locus can be used for identification of truly pathogenic STEC strains and for molecular fingerprinting of the epidemic strains in humans and animals.