Hippocampus and dentate gyrus morphological сhanges in posterity of female rats after receiving PgE2 for labor induction. Zaporizhzhia State Medical University, Zaporizhzhia, Ukraine ABSTRACT. Background. The effect of labor stimulation on the brain structure still remains an unexplored issue. Objective. To determine the morphological hippocampus and dentate gyrus changes in laboratory rats on the first day of life after intravaginal injection of prostaglandin E2 for labor induction. Methods. The changes in the structure of hippocampus and dentate gyrus in posterity of white syngenic rats on the first day of life have been studied. Pregnant females of the experimental group were injected PgE2 in the form of a gel intravaginally to stimulate labor on the 22th day of pregnancy. The duration of the experimental rats pregnancy amounted to 23 day, in the intact group -23-24 day after conceiving. The cerebral hemisphere was fixed in a 10% neutral formalindegid solution, dehydrated in an ascending battery of ethyl spirits. 5 μm paraffin sections were stained with hematoxylin and eosin. The thickness of the layers of hippocampus and dentate gyrus, the number of cells of the granular and pyramidal layers per unit area and their sizes, the area of the neurons nuclei of hippocampus and dentate gyrus were determined in the histological samples. Results. Hippocampus and dentate gyrus in posterity of female rats after receiving PgE2 for labor induction is characterized by a thinning of the pyramidal and granular layers, a decrease in the area of the neurons nuclei, and a decrease in the perimeter of the neurons pericarion neurons in all the studied zones. The decrease in the number of cells is determined only in the dentate gyrus. Conclusion. 1. On the 1st day of life in posterity of female rats after receiving PgE2 for for labor induction there is a tendency to thinning of the pyramidal layer of CA1, CA2 and CA3 fields of hippocampus in combination with a decrease of neurons size of the CA1 field of hippocampus in the experimental group compared to the intact one. 2. In experimental rats there is a decrease of the area of neurons nuclei in the regions CA1, CA2, CA3 and the dentate gyrus compared with the control group. 3. The morphological changes of the hippocampus and dentate gyrus in posterity of female rats after receiving PgE2 for labor induction correspond to the brain changes after experimental fetal hypoxia.

Grigorieva E.A., Mamay I.Y. Cerebellar cortex сhanges in posterity of female rats receiving PgE2 for induction of parturition. ABSTRACT. Background. The effect of birth stimulation on the brain structure still remains an unexplored issue. Objective. To determine the morphological cerebellar cortex changes in laboratory rats during the postnatal period after intravaginal injection of prostaglandin E2 for labor induction. Methods. The changes in the structure of cerebellar cortex in posterity of white syngenic rats from the 14th to the 60th day of life have been studied. Pregnant females of the experimental group were injected PgE2 in the form of a gel intravaginal to stimulate labor on the 20th day of pregnancy. The duration of pregnancy in the rats of the experimental group was 21 day, in the rats of intact group-23-24 days after conception. The beginning of pregnancy was established by the method of vaginal smears stained with methylene blue; presence the sperm in smears was taken for 0 day of pregnancy. The cerebellum was fixed in a 10% neutral formalin solution, dehydrated in an ascending battery of ethyl spirits. 5 μm paraffin sections were stained with hematoxylin and eosin. The thickness of the molecular and granular layers of the cerebellar cortex, the number of cells of the granular layer per unit area, the number of Purkinje cells and their sizes were determined in the histological samples. Data are processed by the variation statistic method. The results are significant for p <0.05. Results. It is settled that at day 14th after birth there are no significant changes in the thickness of cerebellum molecular layer in posterity of female rats receiving PgE2 for induction of labor. From 21st to 60th day of life the thickness of the molecular layer doesn't vary considerably in group over age and in comparison with intact group. The thickness of the granular layer tends to thinning in the experimental group compared to intact from 21st to 60st day of life. Also there is a reduction of the absolute number of cells in the granular layer per unit area from 21st to 60st day of life in experimental animals. Conclusion. Purkinje cells in the experimental and intact animals did not differ in their shape, location, size; however, there is an increase of distance between the Purkinje cells at all stages of development in experimental animals compared to the intact group.

The response to perinatal hypoxia, developing in stimulating generic activity, is the activation of microglia, which induces the development of local inflammation of the brain and leads to the death of neurons. The formation of the hippocampus supports important physiological and behavioral functions, including spatial learning and memory, and is part of the brain, which is especially vulnerable to changes in blood glucose and oxygen. Thus, the study of the features of the development of hippocampal formation in the postnatal period after stimulating generic activity is relevant. The purpose of the study was to study the features of Glial fibrillary acidic protein and NeuN expression in the hippocampal formation in posterity of female rats after PgE2 injection for labor induction. Materials and methods. Pregnant females of the experimental group on the twenty-second day of pregnancy were injected intravaginally with PGE2 in the form of a gel to stimulate the generic activity. Birth occurred on the twenty-third day after conception. Birth in the intact group of rats occurred on the 23-24th day after conception. The large hemispheres of the rat brain were fixed in a 10% neutral formal solution, dehydrated in an ascending alcohol battery. For immunohistochemical studies, paraffin sections were used with 3 microns with a thickness of 3 microns. Glial fibrillary acidic protein Mouse Monoclonal Antibody (Santa Cruz Biotechnology, Inc.) is used to detect astrocytes (Santa Cruz Biotechnology, Inc.). NeuN Mouse Monoclonal Antibody (Santa Cruz Biotechnology, Inc.) was used to identify neurons on the 1st, 7th, 14th, 45th days after birth in histological cuts of hippocampus and gear, using a program for analyzing and processing images Image J, studied the relative area occupied by Glial fibrillary acidic protein + NeuN + cells. Data is processed by variation statistics. The results are reliable at p <0.05. All animal experiments were performed according to international principles of the European Convention for the Protection of Vertebrate Animals Used for Experimental and Other Scientific Purposes” (Strasbourg, 18.03.86) and the Law of Ukraine No. 1759-VI (15.12.2009) On the Protection of Animals from Cruelty. Results and discussion. We identified that by the changes in the hippocampus and the toothed gyrus of the rats after induction of labor, increased Glial fibrillary acidic protein expression on the first day after birth and reducing the NeuN expression on the 14th and 45th day of life in experimental animals compared to the control group were included. Conclusion. The density of the distribution of Glial fibrillary acidic protein + cells in the hippocampus and the dentate gyrus of rats changes wavily throughout the first month and a half of postnatal life. In the offspring of rats, after stimulation of labor on the first day of life, a reliable increase in the relative area occupied by Glial fibrillary acidic protein + astrocytes is determined compared to the control (49.3±2.6% and 36.8±5.9%, respectively). In the hippocampus and the dentate gyrus of rats after stimulation of labor during the first 45 days after birth, the gradual decrease in the relative area occupied by NeuN + neurons is determined, in contrast to the control animals, in which this index practically does not change. On the 14th and 45th days, the index of the relative area occupied by NeuN + neurons in experimental rats is reliably lower than in control (p <0.05).

The aim: To determine the peculiarities of electron microscopic hippocampal formation development characteristics in postetry of rats during two first weeks of postnatal life after intravaginal injection of prostaglandin E2 for labor induction. Materials and methods: The ultrastructural changes of hippocampal formation in posterity of white syngenic rats at the 1st, 7th and 14th days of postnatal life were examined. In this study we used electron-microscopic method. Brain tissue from experimental animals underwent standart stages necessary for electron microscopy and poured into pure Epon. Epon polymerization was carried out in two stages at 36 ° C (12 h) and 56 ° C (24 h). Ultrathin (50-60 nm) sections were obtained on a PowerTome RMC Boeckeler ultratome and then contrasted according to the E. Reynolds method. Ultrathin sections were studied in a PEM-100 electron microscope with an accelerating voltage 60 kV. Results: Based on the obtained data in the study of the hippocampal formation in postery of rats after induction of labor, analysis of the literature devoted to the electron microscopic study of the brain after ischemic injuries, it can be concluded that on the background of stimulation of labor by PgE2, changes corresponding to ischemic damage take place in the rat brain. Conclusions: In posterity of rats after receiving PgE2 for labour induction it was revealed microcirculatory changes; edema of the presynaptic endings, synaptic vesicles aggregation in the center of the presynaptic processes, swelling and destruction of mitochondria; oligodendroglia changes; ultrastructural changes in neurons like edema and vacuolization of mitochondria.