The Effect Of Intrauterine Hypoxia On Testicular Reproductive Function

Goal — to assess the effect of antenatal hypoxia of various origins on the morphology and reproductive function of the testes of newborn and mature rats in experiment. Material and Methods — In experiments 15 white outbred female rats aged 4 to 10 months with a weight of 200±30 g were used. Laboratory animals were randomly divided into 2 experimental and 1 control groups, 5 females each. The first group underwent normobaric hypoxia throughout pregnancy (21 days). Hypoxia modeling was conducted in accordance with the method of N.N. Karkishchenko (2010). The second group underwent hemic hypoxia during the second and third week of pregnancy, in accordance with the method of L.M. Sosedova (2012). The third (control) group was not exposed to any effect throughout pregnancy. Results — in the testicles of newborn rats of the experimental groups, the decrease of tubule diameter was observed, the increase of stroma area and development of interstitial edema were noted. In the group of hemic hypoxia, a significant decrease in the number of Leydig cells was noted. In the tissues of the testicles of mature rats, who underwent antenatal hypoxia, a decrease of tubule diameter, a significant decrease in the spermatogenesis index and a decrease of spermatogonia number were noted. The developed damage of spermatogenic epithelium in experimental groups of newborns and mature rats was confirmed by marked expression of the apoptosis marker (Bax), weak expression of proliferation markers (Ki-67) and receptor of receptor of fibroblast growth factor (FGFR). Conclusion — in animals with chronic hypoxia of various origins, there is an inhibition of spermatogenesis and a violation of the spermatogenetic function of the testicular seminiferous tubules.

Antenatal Hypoxia Affects Pulmonary Artery Contractile Functions via Downregulating L‐type Ca 2+ Channels Subunit Alpha1 C in Adult Male Offspring

Background Antenatal intrauterine fetal hypoxia is a common pregnancy complication that has profound adverse effects on an individual's vascular health later in life. Pulmonary arteries are sensitive to hypoxia, but adverse effects of antenatal hypoxia on pulmonary vasoreactivities in the offspring remain unknown. This study aimed to determine the effects and related mechanisms of antenatal hypoxia on pulmonary artery functions in adult male offspring. Methods and Results Pregnant Sprague‐Dawley rats were housed in a normoxic or hypoxic (10.5% O 2 ) chamber from gestation days 10 to 20. Male offspring were euthanized at 16 weeks old (adult offspring). Pulmonary arteries were collected for vascular function, electrophysiology, target gene expression, and promoter methylation studies. In pulmonary artery rings, contractions to serotonin hydrochloride, angiotensin II, or phenylephrine were reduced in the antenatal hypoxic offspring, which resulted from inactivated L‐type Ca 2+ channels. In pulmonary artery smooth muscle cells, the basal whole‐cell Ca 2+ currents, as well as vasoconstrictor‐induced Ca 2+ transients were significantly reduced in antenatal hypoxic offspring. In addition, increased promoter methylations within L‐type Ca 2+ channel subunit alpha1 C were compatible with its reduced expressions. Conclusions This study indicated that antenatal hypoxia programmed long‐lasting vascular hypocontractility in the male offspring that is linked to decreases of L‐type Ca 2+ channel subunit alpha1 C in the pulmonary arteries. Antenatal hypoxia resulted in pulmonary artery adverse outcomes in postnatal offspring, was strongly associated with reprogrammed L‐type Ca 2+ channel subunit alpha1 C expression via a DNA methylation‐mediated epigenetic mechanism, advancing understanding toward the effect of antenatal hypoxia in early life on long‐term vascular health.

DNA Methylation-Reprogrammed Ang II (Angiotensin II) Type 1 Receptor-Early Growth Response Gene 1-Protein Kinase C ε Axis Underlies Vascular Hypercontractility in Antenatal Hypoxic Offspring

As the most common clinical stress during mid and late pregnancy, antenatal hypoxia has profound adverse effects on individual’s vascular health later in life, but the underlying mechanisms are still not understood. The purpose of this study was to reveal the mechanisms of the acquired vascular dysfunction in offspring imposed by antenatal hypoxia. Pregnant rats were housed in a normoxic or hypoxic (10.5% oxygen) chamber from gestation day 10 to 21. Male offspring were euthanized at gestational day 21 (fetus) or postnatal 16 weeks old (adult offspring). Mesenteric arteries were collected for examining Ang II (angiotensin II)–mediated vascular contractility, gene expression, and promoter methylation. Antenatal hypoxia increased vascular sensitivity to Ang II, which was resulted by an upregulated AT1R (angiotensin II type 1 receptor). The increased AT1R was correlated with a hypomethylation-mediated activated transcription of Agtr1a (alpha subtype of AT1R). In addition, we presented evidences that there was an AT1R-Egr1 (early growth response gene 1)-PKCε (ε isoform of protein kinase C) axis in vasculature; AT1R could modulate PKCε expression via upregulating Egr1; Egr1 mediated transcription activation of PKCε via Egr1 binding sites in PKCε gene promoter. Overall, antenatal hypoxia activated AT1R-Egr1-PKCε axis in vasculature, eventually predisposed offspring to vascular hypercontractility. This is the first description that antenatal hypoxia resulted in vascular adverse outcomes in postnatal offspring, was strongly associated with reprogrammed gene expression via a DNA methylation-mediated epigenetic mechanism, advancing understanding toward the influence of adverse antenatal factors in early life on long-term vascular health.

Multi-Omics Integration Reveals Short and Long-Term Effects of Gestational Hypoxia on the Heart Development

Antenatal hypoxia caused epigenetic reprogramming of methylome and transcriptome in the developing heart and increased the risk of heart disease later in life. Herein, we investigated the impact of gestational hypoxia in proteome and metabolome in the hearts of fetus and adult offspring. Pregnant rats were treated with normoxia or hypoxia (10.5% O2) from day 15 to 21 of gestation. Hearts were isolated from near-term fetuses and 5 month-old offspring, and proteomics and metabolomics profiling was determined. The data demonstrated that antenatal hypoxia altered proteomics and metabolomics profiling in the heart, impacting energy metabolism, lipid metabolism, oxidative stress, and inflammation-related pathways in a developmental and sex dependent manner. Of importance, integrating multi-omics data of transcriptomics, proteomics, and metabolomics profiling revealed reprogramming of the mitochondrion, especially in two clusters: (a) the cluster associated with “mitochondrial translation”/“aminoacyl t-RNA biosynthesis”/“one-carbon pool of folate”/“DNA methylation”; and (b) the cluster with “mitochondrion”/“TCA cycle and respiratory electron transfer”/“acyl-CoA dehydrogenase”/“oxidative phosphorylation”/“complex I”/“troponin myosin cardiac complex”. Our study provides a powerful means of multi-omics data integration and reveals new insights into phenotypic reprogramming of the mitochondrion in the developing heart by fetal hypoxia, contributing to an increase in the heart vulnerability to disease later in life.

Prenatal hypoxia-induced epigenomic and transcriptomic reprogramming in rat fetal and adult offspring hearts

The molecular mechanism of antenatal hypoxia impacting on fetal heart development and elevated risk of heart disease of adult offspring is poorly understood. We present a dataset integrating DNA methylome and transcriptome analyses of antenatal hypoxia affecting rat fetal and adult offspring hearts to understand hypoxia-mediated epigenomic reprogramming of the heart development. We showed that antenatal hypoxia not only induced DNA methylomic and transcriptomic changes in the fetal hearts, but also had a delayed and lasting effect on the adult offspring hearts. Of interest, antenatal hypoxia induced opposite changes in DNA methylation patterns in fetal and adult hearts, with a hypermethylation in the fetus and a hypomethylation in the adult. An extensive preprocessing, quality assessment, and downstream data analyses were performed on the genomic dataset so that the research community may take advantage of the public resource. These dataset could be exploited as a comprehensive resource for understanding fetal hypoxia-mediated epigenetic reprogramming in the heart development and further developmental programming of heart vulnerability to disease later in life. Figshare doi: 10.6084/m9.figshare.9948572

Effect of neonatal administration of the opioid peptide dalargin on long-term cerebral consequences of antenatal hypoxia

Цель исследования - анализ влияния d/m-агониста даларгина (Tyr - D-Ala - Gly - Phe - Leu - Arg) на морфофункциональные показатели головного мозга у половозрелых белых крыс Вистар, перенесших антенатальную гипоксию. Методика. Крысы-самки подвергались воздействию гипобарической гипоксии с 15-х по 19-е сут. гестации. Потомство было разделено на 2 группы: 1) животным группы «Антенатальная гипоксия» (n = 12) интраперитонеально вводили 0,1 мл физиологического раствора с 2-х по 6-е сут. жизни; 2) животным группы «Антенатальная гипоксия + даларгин» (n = 17) в те же сроки интраперитонеально вводили даларгин в дозировке 100 мкг/кг. Группа «Контроль» (n = 25) включала потомство крыс-самок, не подвергавшихся действию гипоксии в период гестации. В гистологических препаратах головного мозга 60-суточных крыс-самцов исследуемых групп определяли площадь ядер и ядрышек нейронов II и V слоев неокортекса и поля СА1 гиппокампа. Активность процессов свободнорадикального окисления в гомогенатах головного мозга определяли методом хемилюминисценции. Поведенческие реакции оценивали в тестах «Открытое поле» и «Приподнятый крестообразный лабиринт». Результаты. У животных группы «Антенатальная гипоксия» выявлено уменьшение массы тела и массы головного мозга; уменьшение числа ядрышек в нейронах II слоя неокортекса и гиппокампа, уменьшение площади ядер нейронов V слоя неокортекса и снижение площади ядрышек нейронов всех исследованных зон; повышение локомоторной активности; активация свободнорадикального окисления в гомогенатах мозга. Введение даларгина уменьшало морфофункциональные церебральные последствия антенатальной гипоксии. Заключение. Показан эффект даларгина для коррекции отдаленных церебральных последствий перенесенной антенатальной гипоксии в эксперименте. The aim of the study was to analyze the effect of d/m-agonist dalargin (Tyr-D-Ala-Gly-Phe-Leu-Arg) on brain morphology and function in mature albino rats exposed to antenatal hypoxia. Methods. Female rats were exposed to hypobaric hypoxia from gestation day 15 to day 19 day. The offspring was divided into 2 groups: 1) the first group, antenatal hypoxia (n = 12), where rats were injected with 0.1 ml of saline from 2 to 6 days of life, 2) the second group, antenatal hypoxia + dalargin (n = 17), where rats were injected with the peptide dalargin (100 mg/kg, i.p.) from 2 to 6 days of life. The control group (n = 25) included offspring of intact female rats. The size of neuronal nuclei and nucleoli in neocortical layers II and V and hippocampal area CA1 were measured on histological slides of the brain from 60-day old male rats. Intensity of free radical oxidation was determined by chemiluminescence in brain homogenates. Rat behavior was evaluated using the open field test and the elevated plus-maze test. Results. Antenatal hypoxia decreased body weight and weight of cerebral hemispheres in 60-day old male albino rats compared with the control. Antenatal hypoxia decreased the number of neuronal nucleoli in layer II of the neocortex and hippocampal area CA1, reduced neuronal nucleus size in layer V of the neocortex and the total area of neuronal nucleoli in all examined brain areas of 60-day-old male albino rats. Animals of this experimental group displayed increased motor activity. The chemiluminescence study of brain homogenates from 60-day-old animals showed increased free radical generation in brain tissues. Administration of dalargin reduced the morphofunctional cerebral consequences of antenatal hypoxia. Conclusion. Dalargin can be used for correcting long-term cerebral consequences of antenatal hypoxia.