The first vital stage in the developmental program occurs at the time before implantation, after fertilization, and before implantation of the fetus in the uterus. This period represents a vulnerable stage because the epigenome undergoes dynamic changes in DNA met More
The first vital stage in the developmental program occurs at the time before implantation, after fertilization, and before implantation of the fetus in the uterus. This period represents a vulnerable stage because the epigenome undergoes dynamic changes in DNA methylation profiles. Changes in early embryonic reprogramming can disrupt DNA methylation patterns and cause permanent changes in the growth program, leading to the onset of adverse health outcomes in offspring. Although there are many evidences that exposure to harmful substances during embryonic development before implantation can cause lasting epigenetic changes in offspring, the mechanisms are not yet fully understood. Since the physiological or pathological changes in DNA methylation can occur in response to environmental cues, a suitable environment plays an important role in fetal growth success. In this review article, we investigated the mechanisms involved in fetal epigenetic reprogramming during DNA methylation and maternal environmental stressors, such as the effects of paraquat herbicide during the pre-implantation stages of the embryo.
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Desmopressin acetate (DA) is one of the synthetic replacements of vasopressin. Considering the possible effects of this medication on the reproductive system, in the present study the effects of this medication during fetal and neonatal development of the hypothalamic p More
Desmopressin acetate (DA) is one of the synthetic replacements of vasopressin. Considering the possible effects of this medication on the reproductive system, in the present study the effects of this medication during fetal and neonatal development of the hypothalamic pituitary gonadal (HPG) axis on sexual hormones of peripubertal male rat offspring was determined. In this experimental study fifty female and twenty adult male wistar rats were used. after becoming pregnant, females were divided into five groups of ten including the control group (no treatment), Sham group 1 and experimental group 1 which received intraperitoneal injection of distilled water and 6mcg/Kg/day DA, prenatally, and Sham group 2 and experimental group 2 that received nothing, but their offspring received intraperitoneal injection of distilled water and 6mcg/Kg/day DA, neonatally. At ninth weeks after birth, the concentration of sexual hormones was measured by Electrochemiluminescence. The results were statistically analyzed by one-way ANOVA test. The results indicate that the concentration of sexual hormones in prenatally and neonatally treated male rats was not significantly different than the control group. It is suggested that DA doesnandrsquo;t cross the placenta and doesnandrsquo;t interfere with fetal development of HPG axis of male rat offspring. Also, because of the stopped development of leydig cells and its inactivated receptors during neonatal period, the steroidogenesis of leydig cells during pripubertal period wouldnandrsquo;t undergo the effects of DA which was injected at the first week of life.
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Stress is a strong stimulant that is considered as a damaging factor for a number of psychiatric and neurobiological disorders. Among different periods of life, embryonic life has a high degree of sensitivity and flexibility; hence, maternal experiences during pregnancy More
Stress is a strong stimulant that is considered as a damaging factor for a number of psychiatric and neurobiological disorders. Among different periods of life, embryonic life has a high degree of sensitivity and flexibility; hence, maternal experiences during pregnancy can form and predict the behavior of her descendent. In the present study, a new model of social stress was used during the rat pregnancy period to examine its influence over the behavior of adolescent offspring. Twenty Wistar rats (weighed approximately150-200gr) were used. After gestation, rats were divided into a control group and a stress group. The stress group members were subjected to restraint stress and predator stress with social instability since the second week of pregnancy. The effect of maternal stress was studied in offspring by dark-light box test during adolescence. The stress group showed a significant increase in the delay time for the first entry into the light box (T1) in comparison to the control group (p =0.0020(. The total time the animal remains in the light box (T2) and the number of the entries into the light box (n) decreased in comparison with control group, respectively )p =0.0003, p <0.0001). These variations were more prominent for males than females for all the above mentioned parameters. The induction of a new social stress model had a significant and different impact on the behavior of the mother and her offspring in adulthood. The results also revealed the difference between male and female resistance to stress.
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