RESUMO
Glyphosate, a non-selective herbicide, causes in mammals cellular mutagenesisand toxic effects at the embryonic, fetal, and placental levels, even at lowconcentrations. This study investigated in rats the effects of perinatal exposureto glyphosate-base herbicide on maternal behavior and the hypothalamic andstriatal levels of dopamine and serotonin. The pups physical and behavioraldevelopment were observed. Glyphosate-base herbicide (50 or 150 mg/kg, peros) was administered in dams during gestation (15º gestational day to 7ºlactation day. The female body weight was recorded throughout the pregnancyand lactation. The dams reproductive performance was observed at postnatalday 2, the open field behavior at postnatal day 5 and the maternal behavior atpostnatal day 6. At weaning, the dams hypothalamic and striatal levels ofdopamine and serotonin were measured. Maternal exposure to both glyphosatebase herbicide doses: i) had few effects on maternal body weight gain; ii)decreased the number and body weight of the pups; iii) impaired the maternalcare; iv) both doses decreased the activity of striatal and hypothalamic dopaminergic systems; v) 50 mg/kg increased and 150 mg/kg decreased theserotoninergic hypothalamic activity. In offspring, no effects on physicaldevelopment but a delay on reflex development. Conclusions: perinatal exposureto glyphosate-base herbicide decreased the maternal care by a reduced striataldopaminergic activity and delayed the pups reflex development.
O glifosato é um herbicida não seletivo, que causa mutagênese celular e efeitostóxicos embrionário, fetal e placentário, mesmo em baixas concentrações. Esteestudo investigou, em ratos, os efeitos da exposição perinatal ao herbicida àbase de glifosato sobre o comportamento materno e os níveis hipotalâmicos eestriatais de dopamina e serotonina. O desenvolvimento físico e comportamentaldos filhotes foi observado. O herbicida (50 ou 150 mg / kg, per os) foiadministrado às mães durante a gestação (15º dia gestacional ao 7º dia delactação. O peso corporal foi registrado durante a gestação e lactação Odesempenho reprodutivo das mães foi observado no dia pós-natal 2, ocomportamento de campo aberto no dia pós-natal 5 e o comportamento maternono dia pós-natal 6. Ao desmame os níveis hipotalâmicos e estriatais da dopaminae da serotonina foram medidos. A exposição materna às duas doses do glifosato:i) teve poucos efeitos sobre o ganho de peso corporal materno; ii) diminuiu onúmero e peso corporal dos filhotes; iii) prejudicou o cuidado materno; iv)ambas as doses diminuíram a atividade dos sistemas dopaminérgicos estriatal ehipotalâmico; v) 50 mg / kg e 150 mg / kg do glifosato diminuíram a atividadehipotalâmica serotoninérgica. Na prole, não houve efeitos no desenvolvimentofísico, mas observou-se atraso no desenvolvimento reflexológico. Poucos efeitosna atividade geral do filhote foram observados. Conclusões: a exposiçãoperinatal ao herbicida à base de glifosato diminuiu o cuidado materno por umaatividade redução da atividade dopaminérgica estriatal e atrasou odesenvolvimento dos reflexos dos filhotes.
Assuntos
Feminino , Animais , Gravidez , Ratos , Comportamento Materno , Dopaminérgicos , Herbicidas/administração & dosagem , Herbicidas/efeitos adversos , Ratos/embriologiaRESUMO
Glyphosate, a non-selective herbicide, causes in mammals cellular mutagenesisand toxic effects at the embryonic, fetal, and placental levels, even at lowconcentrations. This study investigated in rats the effects of perinatal exposureto glyphosate-base herbicide on maternal behavior and the hypothalamic andstriatal levels of dopamine and serotonin. The pups physical and behavioraldevelopment were observed. Glyphosate-base herbicide (50 or 150 mg/kg, peros) was administered in dams during gestation (15º gestational day to 7ºlactation day. The female body weight was recorded throughout the pregnancyand lactation. The dams reproductive performance was observed at postnatalday 2, the open field behavior at postnatal day 5 and the maternal behavior atpostnatal day 6. At weaning, the dams hypothalamic and striatal levels ofdopamine and serotonin were measured. Maternal exposure to both glyphosatebase herbicide doses: i) had few effects on maternal body weight gain; ii)decreased the number and body weight of the pups; iii) impaired the maternalcare; iv) both doses decreased the activity of striatal and hypothalamic dopaminergic systems; v) 50 mg/kg increased and 150 mg/kg decreased theserotoninergic hypothalamic activity. In offspring, no effects on physicaldevelopment but a delay on reflex development. Conclusions: perinatal exposureto glyphosate-base herbicide decreased the maternal care by a reduced striataldopaminergic activity and delayed the pups reflex development.(AU)
O glifosato é um herbicida não seletivo, que causa mutagênese celular e efeitostóxicos embrionário, fetal e placentário, mesmo em baixas concentrações. Esteestudo investigou, em ratos, os efeitos da exposição perinatal ao herbicida àbase de glifosato sobre o comportamento materno e os níveis hipotalâmicos eestriatais de dopamina e serotonina. O desenvolvimento físico e comportamentaldos filhotes foi observado. O herbicida (50 ou 150 mg / kg, per os) foiadministrado às mães durante a gestação (15º dia gestacional ao 7º dia delactação. O peso corporal foi registrado durante a gestação e lactação Odesempenho reprodutivo das mães foi observado no dia pós-natal 2, ocomportamento de campo aberto no dia pós-natal 5 e o comportamento maternono dia pós-natal 6. Ao desmame os níveis hipotalâmicos e estriatais da dopaminae da serotonina foram medidos. A exposição materna às duas doses do glifosato:i) teve poucos efeitos sobre o ganho de peso corporal materno; ii) diminuiu onúmero e peso corporal dos filhotes; iii) prejudicou o cuidado materno; iv)ambas as doses diminuíram a atividade dos sistemas dopaminérgicos estriatal ehipotalâmico; v) 50 mg / kg e 150 mg / kg do glifosato diminuíram a atividadehipotalâmica serotoninérgica. Na prole, não houve efeitos no desenvolvimentofísico, mas observou-se atraso no desenvolvimento reflexológico. Poucos efeitosna atividade geral do filhote foram observados. Conclusões: a exposiçãoperinatal ao herbicida à base de glifosato diminuiu o cuidado materno por umaatividade redução da atividade dopaminérgica estriatal e atrasou odesenvolvimento dos reflexos dos filhotes.(AU)
Assuntos
Animais , Feminino , Gravidez , Ratos , Herbicidas/administração & dosagem , Herbicidas/efeitos adversos , Dopaminérgicos , Ratos/embriologia , Comportamento MaternoRESUMO
During epigenetic reprogramming germ cells activate alternative mechanisms to maintain the repression retrotransposons. This mechanism involves the recruitment of genome defence proteins such as MAEL, PIWIL4 and TDRD9, which associate with piRNAs and promote Line-1 silencing. MAEL, PIWIL4 and TDRD9 form the piP-bodies, which organization and dynamics vary according to the stage of germ cell epigenetic reprogramming. Although these data have been well documented in mice, it is not known how this mechanism operates in the rat. Thus, the aim of this study was to describe the distribution and interaction of MAEL, PIWIL4, TDRD9 and DAZL during rat germ cell development and check whether specific localization of these proteins is related to the distribution of Line-1 aggregates. Rat embryo gonads at 15 days post-conception (dpc), 16dpc and 19dpc were submitted to MAEL, PIWIL4, TDRD9 and DAZL immunolabelling. The gonads of 19dpc embryos were submitted to the double-labelling of MAEL/DAZL, TDRD9/MAEL and PIWIL4/MAEL. The 19dpc gonads were submitted to co-immunoprecipitation assays and fluorescent in situ hybridization for Line-1 detection. MAEL and TDRD9 showed very similar localization at all ages, whereas DAZL and PIWIL4 showed specific distribution, with PIWIL4 showing shuttling from the nucleus to the cytoplasm by the end epigenetic reprogramming. In quiescent 19dpc gonocytes all proteins colocalized in a nuage adjacent to the nucleus. DAZL interacts with PIWIL4 and MAEL, suggesting that DAZL acts with these proteins to repress Line-1. TDRD9, however, does not interact with DAZL or MAEL despite their colocalization. Line-1 aggregates were detected predominantly in the nuclear periphery, although did not show homogeneous distribution as observed for the nuage. In conclusion, the nuage in quiescent rat gonocytes show a very distinguished organization that might be related to the organization of Line-1 clusters and describe the association of DAZL with proteins responsible for Line-1 repression.
Assuntos
Reprogramação Celular , Senescência Celular , Células Germinativas/metabolismo , Animais , Núcleo Celular/metabolismo , Proliferação de Células , DNA Helicases/metabolismo , Proteínas de Ligação a DNA/metabolismo , Células Germinativas/citologia , Gônadas/metabolismo , Masculino , Ligação Proteica , Proteínas de Ligação a RNA/metabolismo , Ratos/embriologia , Ratos/metabolismoRESUMO
3-Monochloropropane-1,2-diol (3-MCPD) is a food contaminant that can be formed during the thermic processing of various foodstuffs. Studies of reproductive toxicology of 3-MCPD are mainly concentrated in the evaluation of possible insults caused by exposure of adult animals. However, the prepuberty might be a period of different susceptibility to chemicals. The aim of this study was to evaluate the effects on reproductive endpoints of the 3-MCPD-exposure prepubertal male rats. Wistar male rats were assigned to 4 groups: control and exposed to 2.5; 5 or 10 mg kg-1 day-1 of 3-MCPD for 30 days by gavage. Testis and epididymis were used for sperm counts and histology analysis. Sertoli cell number and dynamic of the spermatogenesis were evaluated. Sperm were collected from the vas deferens for evaluation of the sperm motility and morphology. Number of sperm with progressive movement, number of Sertoli cells and germ cells and relative daily sperm production were decreased in the groups exposed to 5 and 10 mg kg-1 day-1 of 3-MCPD. Sperm morphology, testicular and epididymal histology were comparable among groups. Results show that 3-MCPD-exposure of rats from prepuberty might cause alterations in spermatogenesis and sperm maturation, similarly to exposure in adulthood.(AU)
3-monocloropropano-1,2-diol (3-MCPD) é um contaminante alimentar formado durante o processamento térmico de vários produtos. Estudos de toxicologia reprodutiva do 3-MCPD estão concentrados principalmente na avaliação de danos causados pela exposição de animais adultos. No entanto, a peri-puberdade pode ser um período de susceptibilidade diferente a produtos químicos. O objetivo deste estudo foi avaliar os efeitos reprodutivos da exposição de ratos machos pré-púberes ao 3- MCPD. Ratos Wistar machos foram divididos em quatro grupos: controle e expostos a 2,5; 5 ou 10 mg kg-1 dia-1 de 3-MCPD durante 30 dias, por gavagem. Os testículos e epidídimos foram usados para contagem espermática e análise histológica. Foram avaliados o número de células de Sertoli e a dinâmica da espermatogênese. Espermatozoides foram coletados a partir dos ductos deferentes para avaliação da motilidade e morfologia. O número de espermatozoides com movimento progressivo, o número de células de Sertoli e de células germinativas e a produção espermática foram reduzidos nos grupos expostos a 5 e 10 mg kg-1 dia-1 de 3-MCPD. A morfologia espermática e histologia testicular e epididimária foram semelhantes entre os grupos. Os resultados mostram que a exposição de ratos ao 3-MCPD, a partir da prépuberdade, pode causar alterações na espermatogênese e na maturação espermática, de forma semelhante à exposição na idade adulta.(AU)
Assuntos
Animais , Masculino , Ratos , Motilidade dos Espermatozoides/genética , Motilidade dos Espermatozoides/fisiologia , Espermatogênese , Ratos/embriologia , Ratos/genéticaRESUMO
The Aim of the present study was to investigate effects of onion juice on semen values of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant status (TAS) compared to Zn sulfate in rats. One hundred and sixty-two Wistar Male rats were randomly allocated into 9 treatment groups (each including 3 groups and 6 replicates). Group 1 served as control and received distilled water. In group 2, animals received 1 cc fresh onion juice. In group 3, rats were offered cc fresh onion juice. Group 4 drenched 15 mg/kg zinc (Zn) sulfate. In group 5, rats were treated with 30 mg/kg Zn sulfate. Group 6 was offered 1cc fresh onion juice + 15 mg/kg Zn sulfate to experimental animals. In group 7, 1 cc fresh onion juice + 30 mg/kg Zn sulfate was provided to rats. Group 8 consumed 2 cc fresh onion juice + 15 mg/kg Zn sulfate. In group 9, animals provided 2 cc fresh onion juice + 30 mg/kg Zn sulfate. All groups were given treatments orally and ad libitum access to chow pellets and fresh water. After 4 weeks semen samples in cauda epididymis were used to determine MDA, SOD, GPx and TAS levels. According to the data, sole onion juice significantly decreased semen MDA level (P < 0.05). Also, a combination between the administration of onion and Zn significantly attenuated sperm MDA (P < 0.05). Sperm GPx level in the co-administration of onion and Zn was significantly altered (P < 0.05). Results suggest that presumably onion juice protects from semen oxidation in rat testes.(AU)
Assuntos
Animais , Ratos , Ratos/embriologia , Ratos/fisiologia , Cebolas/química , Análise do Sêmen/veterinária , Oxidação , Sulfato de Zinco/análise , Sulfato de Zinco/químicaRESUMO
The Aim of the present study was to investigate effects of onion juice on semen values of malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant status (TAS) compared to Zn sulfate in rats. One hundred and sixty-two Wistar Male rats were randomly allocated into 9 treatment groups (each including 3 groups and 6 replicates). Group 1 served as control and received distilled water. In group 2, animals received 1 cc fresh onion juice. In group 3, rats were offered cc fresh onion juice. Group 4 drenched 15 mg/kg zinc (Zn) sulfate. In group 5, rats were treated with 30 mg/kg Zn sulfate. Group 6 was offered 1cc fresh onion juice + 15 mg/kg Zn sulfate to experimental animals. In group 7, 1 cc fresh onion juice + 30 mg/kg Zn sulfate was provided to rats. Group 8 consumed 2 cc fresh onion juice + 15 mg/kg Zn sulfate. In group 9, animals provided 2 cc fresh onion juice + 30 mg/kg Zn sulfate. All groups were given treatments orally and ad libitum access to chow pellets and fresh water. After 4 weeks semen samples in cauda epididymis were used to determine MDA, SOD, GPx and TAS levels. According to the data, sole onion juice significantly decreased semen MDA level (P < 0.05). Also, a combination between the administration of onion and Zn significantly attenuated sperm MDA (P < 0.05). Sperm GPx level in the co-administration of onion and Zn was significantly altered (P < 0.05). Results suggest that presumably onion juice protects from semen oxidation in rat testes.
Assuntos
Animais , Ratos , Análise do Sêmen/veterinária , Cebolas/química , Ratos/embriologia , Ratos/fisiologia , Oxidação , Sulfato de Zinco/análise , Sulfato de Zinco/químicaRESUMO
O objetivo deste estudo foi investigar o efeito da restrição proteica materna durante prenhez e lactação no testículo de ratos imaturos. Fêmeas de ratos Wistar foram acasaladas e, uma vez confirmada a gestação, foram divididas em dois grupos e alimentadas durante a prenhez e a lactação: grupo desnutrido (GD), dieta com caseína 8%, e grupo controle (GC), dieta com caseína 17%. Após o desmame, os machos de ambas as proles receberam a dieta normal até os 35 dias de idade, quando ocorreu a eutanásia. O peso corporal e o peso testicular diminuíram no GD com relação ao GC. A densidade volumétrica dos túbulos seminíferos foi maior no GC, assim como o espaço intertubular aumentou no GD. O número de túbulos seminíferos luminados foi maior no GC comparado ao GD. Diâmetro tubular, altura do epitélio seminífero e comprimento total dos túbulos seminíferos diminuíram no GD. Espermátides arredondadas foram frequentemente encontradas nas seções transversais do GC. Por outro lado, espermatócitos I em prófase foram o tipo celular mais frequentemente encontrado no GD. A desnutrição durante a gestação e a lactação em ratos Wistar machos alteraram parâmetros morfométricos testiculares relacionados ao compartimento tubular e atrasou o início da espermatogênese.(AU)
Current study investigates the effects of maternal protein restriction during pregnancy and lactation on the testis of immature rats. Female Wistar rats were mated and, after confirming pregnancy, they were divided into two groups: undernourished group (UG) fed on a diet with casein 8%, and control group (CG) fed on a diet with casein 17 %, during pregnancy and lactation. After weaning, male offspring from the two experimental groups were fed on normal diet up to 35 days old when they were euthanized. Body and testicular weights decreased in UG when compared to those in CG. Volumetric density of seminiferous tubules was higher in CG whilst intertubular space increased in UG. The number of lumenated seminiferous tubules was higher in CG than in UG. Tubular diameter, seminiferous epithelium height and total length of seminiferous tubules were lower in UG. Round spermatids were frequently found in seminiferous tubules cross-section of CG. On the other hand, spermatocytes I in prophases was the germ cell commonly found in seminiferous tubules cross-sections of UG. Undernutrition during pregnancy and lactation period of the male Wistar rats altered the morphometric testicular parameters related to tubular compartment and delayed the onset of spermatogenesis.(AU)
Assuntos
Animais , Feminino , Lactente , Ratos , Ratos/anatomia & histologia , Ratos/embriologia , Necessidade Proteica , Diagnóstico Pré-Natal , DesnutriçãoRESUMO
The evolutionary history of Hystricognathi is associated with major transformations in their placental system. Data so far indicate that key characters are independent from size dimensions in medium to very large species. To better understand the situation in smaller species, we analyzed placental development in a spiny rat, Thrichomys laurentinus. Fourteen individuals ranging from early implantation to near term were investigated by histology, immunohistochemistry, proliferation activity and electron microscopy. Placentation in Thrichomys revealed major parallels to the guinea pig and other hystricognath rodents with respect to the early and invasive implantation, the process of trophoblast invasion, the internal organization of the labyrinth and the trophospongium as well as the establishment of the complete inverted yolk sac placenta. In contrast to systematically related small-sized species, the placental regionalization in Thrichomys was characterized by a remarkable lobulated structure and associated growing processes. Reverse to former perspectives, these conditions represented ancient character states of hystricognaths. The subplacenta was temporarily supplied by both the maternal and fetal blood systems, a rare condition among hystricognaths. The extraplacental trophoblast originating from the subplacenta was partly proliferative in mid gestation. In conclusion, the presented results indicated that only minor variations occurred in small-sized hystricognath species, independent of their systematic interrelationships. Previous views were supported that placentation in hystricognaths followed an extraordinary stable pattern, although the group had distinct habitats in South America and Africa that were separated 30-40 million years ago.
Assuntos
Placenta , Ratos/fisiologia , Saco Vitelino , Animais , Feminino , Placenta/irrigação sanguínea , Placenta/citologia , Gravidez , Ratos/classificação , Ratos/embriologiaRESUMO
La homeostasis de los tejidos que constituyen a los seres vivos es regulada por los procesos de proliferación y apoptosis celular. El modelo de estrés crónico intermitente por inmovilización durante la gestación puede alterar diversos mecanismos que mantienen la homeostasis del organismo, los cuales son motivo de estudios actuales. En estudios previos se comprobó variaciones significativas en el peso de las glándulas adrenales y en los niveles plasmáticos de PRL, estrógenos y CORT. Bajo la hipótesis que el estrés crónico produce modificaciones en los procesos de proliferación y apoptosis en las glándulas adrenales de ratas gestantes, los objetivos fueron cuantificar las células en proliferación y apoptosis mediante la utilización de técnicas inmunocitoquímicas en la corteza adrenal de ratas en la segunda mitad de la gestación, y comprobar las características ultraestructurales del proceso apoptótico con microscopía electrónica de transmisión. Material y Métodos: En condiciones de bioterio controladas, se estudió la glándula adrenal de ratas de 12, 17 y 21 días de gestación, controles (RC) y experimentales (RE) sometidas a un estrés crónico, intermitente, homotípico e intenso. Se usaron técnicas combinadas de inmunomarcación, análisis estereológico y cuantificación de imágenes de cortes alternados para determinar las variaciones del fenómeno apoptótico y proliferativo que presentan las diferentes poblaciones celulares de la corteza adrenal. El tratamiento estadístico se realizó con los Softwares InfoStat y el SAS 9.1. Se aplicó ANOVA de una y tres vías y la distribución de Poisson de un modelo logarítmico lineal con efecto de grupo, tiempo e interacciones. Las diferencias fueron consideradas significativas si p<0.05. Resultados Apoptosis: a. En Ratas Gestantes Controles y Estresadas: 1. El índice apoptótico disminuyó a medida que progresó la gestación(AU)
SUMMARY: Homeostasis of tissues is regulated by cellular proliferation and apoptosis processes. Intermittent chronic stress by immobilization during gestation may alter several mechanisms that maintain the organism homeostasis. Those mechanisms are object of several studies. Previous studies using the immobilization model have shown significant variations in adrenal glands weight and plasmatic levels of PRL, estrogens and CORT. Under the hypothesis that chronic stress causes changes in proliferation and apoptosis processes in adrenal glands of gestant rats, the main objectives of this study were: 1) to identify and quantify cell nuclei in proliferation and apoptosis using immunocytochemical techniques in adrenal cortex samples of rats in the second half of gestation and, 2) to check the ultraestructural haracteristics of apoptotic process by means of transmission electronic microscopy. Materials and Methods: In controlled lab conditions, the adrenal glands of control (RC) and experimental (RE) rats at 12, 17 and 21 days of gestation were studied. Experimental rats were subject to an intermittent, chronic, homotypic and intense stress in order to avoid habituation. A combination of labeling techniques, stereological analysis and image quantification of alternate sections was used to determine the changes in proliferation and apoptosis in the different cell populations of the adrenal cortex. Statistical analyses were performed with InfoStat and SAS 9.1 softwares. Data was analyzed with one and three-way ANOVAs and, a linear logarithmic model with Poisson distribution including group, time and interactions effects(AU)
Assuntos
Animais , Ratos , Apoptose/efeitos dos fármacos , Ratos/embriologia , Proliferação de Células/efeitos dos fármacos , Zona FasciculadaRESUMO
La homeostasis de los tejidos que constituyen a los seres vivos es regulada por los procesos de proliferación y apoptosis celular. El modelo de estrés crónico intermitente por inmovilización durante la gestación puede alterar diversos mecanismos que mantienen la homeostasis del organismo, los cuales son motivo de estudios actuales. En estudios previos se comprobó variaciones significativas en el peso de las glándulas adrenales y en los niveles plasmáticos de PRL, estrógenos y CORT. Bajo la hipótesis que el estrés crónico produce modificaciones en los procesos de proliferación y apoptosis en las glándulas adrenales de ratas gestantes, los objetivos fueron cuantificar las células en proliferación y apoptosis mediante la utilización de técnicas inmunocitoquímicas en la corteza adrenal de ratas en la segunda mitad de la gestación, y comprobar las características ultraestructurales del proceso apoptótico con microscopía electrónica de transmisión. Material y Métodos: En condiciones de bioterio controladas, se estudió la glándula adrenal de ratas de 12, 17 y 21 días de gestación, controles (RC) y experimentales (RE) sometidas a un estrés crónico, intermitente, homotípico e intenso. Se usaron técnicas combinadas de inmunomarcación, análisis estereológico y cuantificación de imágenes de cortes alternados para determinar las variaciones del fenómeno apoptótico y proliferativo que presentan las diferentes poblaciones celulares de la corteza adrenal. El tratamiento estadístico se realizó con los Softwares InfoStat y el SAS 9.1. Se aplicó ANOVA de una y tres vías y la distribución de Poisson de un modelo logarítmico lineal con efecto de grupo, tiempo e interacciones. Las diferencias fueron consideradas significativas si p<0.05. Resultados Apoptosis: a. En Ratas Gestantes Controles y Estresadas: 1. El índice apoptótico disminuyó a medida que progresó la gestación
SUMMARY: Homeostasis of tissues is regulated by cellular proliferation and apoptosis processes. Intermittent chronic stress by immobilization during gestation may alter several mechanisms that maintain the organism homeostasis. Those mechanisms are object of several studies. Previous studies using the immobilization model have shown significant variations in adrenal glands weight and plasmatic levels of PRL, estrogens and CORT. Under the hypothesis that chronic stress causes changes in proliferation and apoptosis processes in adrenal glands of gestant rats, the main objectives of this study were: 1) to identify and quantify cell nuclei in proliferation and apoptosis using immunocytochemical techniques in adrenal cortex samples of rats in the second half of gestation and, 2) to check the ultraestructural haracteristics of apoptotic process by means of transmission electronic microscopy. Materials and Methods: In controlled lab conditions, the adrenal glands of control (RC) and experimental (RE) rats at 12, 17 and 21 days of gestation were studied. Experimental rats were subject to an intermittent, chronic, homotypic and intense stress in order to avoid habituation. A combination of labeling techniques, stereological analysis and image quantification of alternate sections was used to determine the changes in proliferation and apoptosis in the different cell populations of the adrenal cortex. Statistical analyses were performed with InfoStat and SAS 9.1 softwares. Data was analyzed with one and three-way ANOVAs and, a linear logarithmic model with Poisson distribution including group, time and interactions effects