ABSTRACT
Objective:To explore the effects of early-life maternal deprivation on depressive-like behavior and neurogenesis in the granular layer of hippocampus in adolescent rats (6-7 weeks old).Methods:Neonatal rats were randomly divided into maternal deprivation group and control group, with 3 litters in each group.Rats in the maternal deprivation group were given maternal deprivation from 1 to 14 days after birth and rats in the control group were caged with the mother rats and raised normally.The body weight of rats at 5-6 weeks old was recorded and the increased body weight was calculated.When the rats were 6 weeks old, the sucrose preference test was carried out.Then the rats were killed and immunofluorescence histochemistry was applied to compare the expression of Ki67 and Nestin positive cells in the dentate gyrus of hippocampus.SPSS 22.0 software was used for statistical analysis.The data of the two groups were tested to conform to the normal distribution, and then t-test was carried out. Results:There was significant difference in body weight growth between the two groups at the age of 5-6 weeks.Compared with the control group, rats in the maternal deprivation group had lower body weight growth ((20.57±2.19) g, (30.57±1.25) g, t=3.96, P<0.01)) and lower sucrose preference rate((58.38±53.14)%, (73.88±3.67)%, t=3.21, P<0.01). The results of immunofluorescence showed that the number of Ki67 positive cells in the granular layer of hippocampus in the maternal deprivation group was less than that in the control group ((5.13±0.31), (7.60±0.38), t=5.09, P<0.01), and the number of Nestin immunofluorescence positive cells was more than that in the control group ((16.65±0.79), (7.64±0.70), t=8.51, P<0.01). The Nestin immunofluorescence positive cells in the maternal deprivation group had more protrusions and branches, and the morphology was similar to astrocytes, while the immunofluorescence positive cells in the control group had fewer protrusions, and the cell body was oval. Conclusions:Early-life maternal deprivation leads to depressive-like behavior in adolescent rats, which may be associated with the decrease of neurogenesis and activation of astrocytes in the dentate gyrus of the hippocampus.
ABSTRACT
The investigation of the embryonic development of the cerebellum has a long history. The postnatal normal development of the cerebellum in rodents and other animals became a popular topic for morphological investigations nearly a century ago. However, surprisingly, only a few studies are available regarding the prenatal normal development of the rodent cerebellum, especially in guinea pigs. Cell proliferation is essential for the development of the nervous system. The assessment of cell proliferation can be achieved by using various methods. In this study, we investigated the cell proliferation of the cerebellar cortex in guinea pigs at different stages of pregnancy and in postnatal life. Fetuses were obtained by cesarean section at 50 or 60 days of gestation (dg). Immunohistochemistry was performed with proliferating cell nuclear antigen (PCNA) antibody in the cerebellum. Strong PCNA immunoreactivity was observed in the external granular layer (EGL), which is a neurogenic zone in the cerebellum. The proportion of PCNA-IR cells was greater at 1 week than at 60 dg in lobule I, but not lobule VIII. After 50 dg, the width of the EGL continued to decline until 1 week, due to the maturation of the EGL cells. These results demonstrate the pattern of PCNA immunoreactivity in the developing cerebellum of guinea pigs. This serves as a guideline to study abnormal cerebellum development.
Subject(s)
Animals , Female , Pregnancy , Cell Proliferation , Cerebellar Cortex , Cerebellum , Cesarean Section , Embryonic Development , Fetus , Guinea Pigs , Guinea , Immunohistochemistry , Neocortex , Nervous System , Proliferating Cell Nuclear Antigen , RodentiaABSTRACT
Background: Prefrontal cortex (PFC) represents the highest level of integration and control of psychic and behavioral states. Several dysfunctions such as autism, hyperactivity disorders, depression, and schizophrenia have been related with alterations in the prefrontal cortex (PFC). Among the cortical layers of the PFC, layer II shows a particular vertical pattern of organization, the highest cell density and the biggest non-pyramidal/pyramidal neuronal ratio. We currently characterized the layer II cytoarchitecture in human areas 10, 24, and 46. Objective: We focused particularly on the inhibitory neurons taking into account that these cells are involved in sustained firing (SF) after stimuli disappearance. Methods: Postmortem samples from five subjects who died by causes different to central nervous system diseases were studied. Immunohistochemistry for the neuronal markers, NeuN, parvalbumin (PV), calbindin (CB), and calretinin (CR) were used. NeuN targeted the total neuronal population while the rest of the markers specifically the interneurons. Results: Cell density and soma size were statically different between areas 10, 46, 24 when using NeuN. Layer II of area 46 showed the highest cell density. Regarding interneurons, PV+-cells of area 46 showed the highest density and size, in accordance to the proposal of a dual origin of the cerebral cortex. Interhemispheric asymmetries were not identified between homologue areas. Conclusion: First, our findings suggest that layer II of area 46 exhibits the most powerful inhibitory system compared to the other prefrontal areas analyzed. This feature is not only characteristic of the PFC but also supports a particular role of layer II of area 46 in SF. Additionally, known functional asymmetries between hemispheres might not be supported by morphological asymmetries.
Antecedentes: La corteza prefrontal (CPF) representa el nivel más alto de integración y control de funciones psíquicas y comportamentales. Varias patologías como autismo, desórdenes de hiperactividad, depresión y esquizofrenia se han relacionado con alteraciones de la CPF. La lámina II de las áreas que constituyen la CPF posee un patrón de organización vertical, una alta densidad celular y la mayor proporción de neuronas no-piramidal/piramidal. Sin embargo, la distribución del componente inhibitorio en estas regiones no se ha descrito. Objetivo: En el presente estudio nos propusimos caracterizar la lámina II de las áreas 10, 24 y 46 del humano, particularmente su componente inhibitorio teniendo en mente su participación en procesos de actividad sostenida relevantes cuando desaparece el estímulo. Métodos: Se utilizaron muestras de cinco sujetos que fallecieron por causas diferentes a enfermedades del sistema nervioso. Se tomaron secciones de las áreas 10, 24 y 46 de Brodmann y se procesaron con los anticuerpos contra NeuN para determinar la población neuronal total y contra Parvalbumina (PV), Calbindina (CB) y Calretinina (CR) para analizar la población de interneuronas. Resultados: Los resultados no mostraron diferencias interhemisféricas entre las áreas. Sin embargo, las tres áreas seleccionadas son significativamente diferentes entre sí en todos los parámetros analizados. El área 46 posee la mayor densidad y tamaño de interneuronas positivas para PV. Conclusiones: La ausencia de asimetrías morfológicas no permite explicar las asimetrías funcionales. La lámina II del área 46 posee el sistema inhibitorio más poderoso. Teniendo en cuenta la arquitectura modular de las capas supragranulares, este sistema inhibitorio subyace a la actividad sostenida, eje fundamental de la memoria operativa.