Effect of maternal exercise on biochemical parameters in rats submitted to neonatal hypoxia-ischemia

Effects of Resuscitation and Simulation Team Training on the Outcome of Neonates with Hypoxic-Ischemic Encephalopathy in South Tyrol

Background/Objectives: Neonatal hypoxic-ischemic encephalopathy (HIE) due to perinatal complications remains an important pathology with a significant burden for neonates, families, and the healthcare system. Resuscitation and simulation team training are key elements in increasing patient safety. In this retrospective cohort study, we evaluated whether regular constant training of all personnel working in delivery rooms in South Tyrol improved the outcome of neonates with HIE. Methods: We retrospectively analyzed three groups of neonates with moderate to severe HIE who required therapeutic hypothermia. The first group included infants born before the systematic introduction of training and was compared to the second group, which included infants born after three years of regular training. A third group, which included infants born after the SARS-CoV-2 pandemic, was compared with the previous two to evaluate retention of skills and the long-term effect of our training program. Results: Over the three study periods, mortality decreased from 41.2% to 0% and 14.3%, respectively. There was also a significant reduction of patients with subclincal seizures detected only through EEG, from 47.1% in the first period to 43.7% and 14.3% in the second and third study periods, respectively. Clinical manifestations of seizures decreased significantly from 47.1% to 37.5% and 10.7%, respectively, as well as severe brain lesions in ultrasound (US) and MRI. Conclusions: In this study, constant and regular simulation training for all birth attendants significantly decreases mortality and improves the outcome in neonates with moderate to severe HIE. This positive effect seems to last even after a one-year period during which training sessions could not be performed due to the COVID-19 pandemic.

Transcranial Doppler Ultrasonography detection on cerebral infarction and blood vessels to evaluate hypoxic ischemic encephalopathy modeling

BACKGROUND

This study aimed to observe changes of rats' brain infarction and blood vessels during neonatal hypoxic ischemic encephalopathy (NHIE) modeling by Transcranial Doppler Ultrasonography (TCD) so as to assess the feasibility of TCD in evaluating NHIE modeling.

METHODS

Postnatal 7-days (d)-old Sprague Dawley (SD) rats were divided into the Sham group, hypoxic-ischemic (HI) group, and hypoxia (H) group. Rats in the HI group and H group were subjected to hypoxia-1 hour (h), 1.5 h and 2.5 h, respectively. Evaluation on brain lesion was made based on Zea-Longa scores, hematoxylin-eosin (HE) staining and Nissl staining. The brain infarction and blood vessels of rats were monitored and analyzed under TCD. Correlation analysis was applied to reveal the connection between hypoxic duration and infarct size detected by TCD or Nissl staining.

RESULTS

In H and HI modeling, longer duration of hypoxia was associated with higher Zea-Longa scores and more severe nerve damage. On the 1 d after modeling, necrosis was found in SD rats' brain indicated by HE and Nissl staining, which was aggravated as hypoxic duration prolonged. Alteration of brain structures and blood vessels of SD rats was displayed in Sham, HI and H rats under TCD. TCD images for coronal section revealed that brain infarct was detected at the cortex and there was marked cerebrovascular back-flow of HI rats regardless of hypoxic duration. On the 7 d after modeling, similar infarct was detected under TCD at the cortex of HI rats in hypoxia-1 h, 1.5 h and 2.5 h groups, whereas the morphological changes were deteriorated with longer hypoxic time. Correlation analysis revealed positive correlation of hypoxic duration with infarct size detected by histological detection and TCD.

CONCLUSIONS

TCD dynamically monitored cerebral infarction after NHIE modeling, which will be potentially served as a useful auxiliary method for future animal experimental modeling evaluation in the case of less animal sacrifice.

Impact of maternal physical exercise on inflammatory and hypothalamic-pituitary-adrenal axis markers in the brain and lungs of prenatally stressed neonatal mice

This study aimed to evaluate the effects of maternal exercise on alterations induced by prenatal stress in markers of the inflammatory process and the hypothalamic-pituitary-adrenal axis in the brain and lungs of neonatal mice. Female Balb/c mice were divided into three groups: control, prenatal restraint stress, prenatal restraint stress and physical exercise before and during the gestational period. On day 0 (PND0) and 10 (PND10), mice were euthanized for brain and lung analyses. The gene expression of GR, MR, IL-6, IL-10, and TNF in the brain and lungs and the protein expression of MMP-2 in the lungs were analyzed. Maternal exercise reduced IL-6 and IL-10 gene expression in the brain of PND0 mice. Prenatal stress and maternal exercise decreased GR, MR, IL-6, and TNF gene expression in the lungs of PND0 mice. In the hippocampus of PND10 females, exercise inhibited the effects of prenatal stress on the expression of MR, IL-6, and IL-10. In the lungs of PND10 females, exercise prevented the decrease in GR expression caused by prenatal stress. In the hippocampus and lungs of PND10 males, prenatal stress decreased GR gene expression. Our findings confirm the effects induced by prenatal stress and demonstrate that physical exercise before and during the gestational period may have a protective role on inflammatory changes.

Maternal Swimming Exercise During Pregnancy Improves Memory Through Enhancing Neurogenesis and Suppressing Apoptosis via Wnt/β-Catenin Pathway in Autistic Mice

Purpose

Wnt pathway is closely related to neurodevelopmental process associated with cognitive function. After administration of valproic acid to the pregnant mice, the effect of swimming exercise of pregnant mice on the memory, neuronal production, and apoptosis of pups was studied in relation with Wnt/β-catenin signaling pathway.

Methods

On day 12 of pregnancy, mice were injected subcutaneously with 400-mg/kg valproic acid. The pregnant mice in the control with swimming exercise group and in the valproic acid injection with swimming exercise group were allowed for swimming for 30 minutes one time per a day, repeated 5 days per a week, during 3 weeks. Step-through avoidance task and Morris water maze task for memory function, immunohistochemistry for 5-bromo-2’-deoxyuridine (BrdU)-positive cells and western blot for brain-derived neurotrophic factor (BDNF), Wnt, β-catenin, Bcl-2 related X protein (Bax), B-cell lymphoma 2 (Bcl-2), cleaved caspase-3 were carried out.

Results

Maternal swimming exercise during pregnancy improved memory function, increased BDNF expression, and neuronal proliferation in the valproic acid injected pups. Maternal swimming exercise during pregnancy suppressed Wnt expression and phosphorylation of β-catenin in the valproic acid injected pups. Maternal swimming exercise inhibited Bax and cleaved caspase-3 expression and increased Bcl-2 expression in the valproic acid injected pups.

Conclusions

Maternal swimming exercise during pregnancy improved memory function by increasing cell proliferation and inhibiting apoptosis through Wnt/β-catenin signaling cascade activation in the valproic acid injected pups. Maternal swimming exercise during pregnancy may have a protective effect on factors that induce autism in the fetus.

Effect of Maternal Exercise on Diet-induced Redox Imbalance in Hippocampus of Adult Offspring

Physical exercise practice has been increasingly recommended in the prevention and treatment of chronic diseases, causing a positive effect from body weight/fat loss to improved cognitive function. Maternal exercise seems to induce the same positive lifelong adaptations to the offspring. We hypothesized that maternal exercise can prevent redox imbalance in adult offspring's hippocampus exposed to a high-fat diet (HFD). Female Wistar rats were divided into three groups before and during pregnancy: (1) sedentary, (2) swimming exercise, and (3) swimming exercise with overload. On 60 days of age, the male pups were divided into standard diet or HFD for one month, yielding normal and HFD subgroups for each maternal condition. Maternal interventions did not alter gestational parameters, birth outcomes, and offspring weight gain from weaning to 90 days of age. The HFD consumption increased body fat, which was not prevented by maternal exercise. Serum glucose levels were increased by HFD, an effect that was prevented by unload maternal exercise. In the hippocampus, both maternal exercise intensities could increase antioxidant defense. Hippocampal redox homeostasis was impaired by HFD, causing increased superoxide levels, which was prevented by exercise without load, while overload caused only a reduction of the effect. In summary, the practice of swimming exercise without overload during pregnancy seems to be more beneficial when evaluated in animal model, preventing HFD induced redox imbalance and increasing antioxidant defense while overload swimming exercise during pregnancy demonstrated a negative effect on offspring submitted to HFD consumption.

Sex-dependent metabolic effects of pregestational exercise on prenatally stressed mice

Stressful events during the prenatal period have been related to hyperactive hypothalamic-pituitary-adrenal (HPA) axis responses as well as metabolic changes in adult life. Moreover, regular exercise may contribute to the improvement of the symptoms associated with stress and stress-related chronic diseases. Therefore, this study aims to investigate the effects of exercise, before the gestation period, on the metabolic changes induced by prenatal stress in adult mice. Female Balb/c mice were divided into three groups: control (CON), prenatal restraint stress (PNS) and exercise before the gestational period plus PNS (EX + PNS). When adults, the plasmatic biochemical analysis, oxidative stress, gene expression of metabolic-related receptors and sex differences were assessed in the offspring. Prenatal stress decreased neonatal and adult body weight when compared to the pregestational exercise group. Moreover, prenatal stress was associated with reduced body weight in adult males. PNS and EX + PNS females showed decreased hepatic catalase. Pregestational exercise prevented the stress-induced cholesterol increase in females but did not prevent the liver mRNA expression reduction on the peroxisome proliferator-activated receptors (PPARs) α and γ in PNS females. Conversely, PNS and EX + PNS males showed an increased PPARα mRNA expression. In conclusion, pregestational exercise prevented some effects of prenatal stress on metabolic markers in a sex-specific manner.

Pathophysiology of hypoxic-ischemic encephalopathy: a review of the past and a view on the future

Hypoxic-ischemic encephalopathy, also referred as HIE, is a type of brain injury or damage that is caused by a lack of oxygen to the brain during neonatal period. The incidence is approximately 1.5 cases per 1000 live births in developed countries. In low and middle-income countries, the incidence is much higher (10‒20 per 1000 live births). The treatment for neonatal HIE is hypothermia that is only partially effective (not more than 50% of the neonates treated achieve an improved outcome). HIE pathophysiology involves oxidative stress, mitochondrial energy production failure, glutaminergic excitotoxicity, and apoptosis. So, in the last years, many studies have focused on peptides that act somewhere in the pathway activated by severe anoxic injury leading to HIE. This review describes the pathophysiology of perinatal HIE and the mechanisms that could be the target of innovative HIE treatments.

Neurological impairments in hypoxic neonates and lactate levels

INTRODUCTION

Metabolic acidosis with increasing lactate concentration develops due to the lack of oxygen in the tissues.

OBJECTIVES

The effect of lactic acidosis on neurological development in the first year of life.

MATERIALS AND METHODS

Our study included 50 newborns with perinatal hypoxia requiring oxygen therapy and 50 healthy newborns. pH, pCO2, pO2, base excess (BE) and lactates from arterialized capillary blood were determined in both groups of newborns, in the first and second hours after birth, and neurological development in the first year of life was estimated.

RESULTS

pH, pCO2, pO2, BE and lactates differed significantly between the groups in the first and second hours after birth p < 0.01. Hypotonia was recorded in 20/50 cases and hypertonia was recorded in 10/50 cases in the first year of life.

CONCLUSION

Lactate concentration may be an indicator of neurological damage in neonates with perinatal hypoxia.

Pregnancy as a valuable period for preventing hypoxia-ischemia brain damage

Neonatal brain Hypoxia-Ischemia (HI) is one of the major causes of infant mortality and lifelong neurological disabilities. The knowledge about the physiopathological mechanisms involved in HI lesion have increased in recent years, however these findings have not been translated into clinical practice. Current therapeutic approaches remain limited; hypothermia, used only in term or near-term infants, is the golden standard. Epidemiological evidence shows a link between adverse prenatal conditions and increased risk for diseases, health problems, and psychological outcomes later in life, what makes pregnancy a relevant period for preventing future brain injury. Here, we review experimental literature regarding preventive interventions used during pregnancy, i.e., previous to the HI injury, encompassing pharmacological, nutritional and/or behavioral strategies. Literature review used PubMed database. A total of forty one studies reported protective properties of maternal treatments preventing perinatal hypoxia-ischemia injury in rodents. Pharmacological agents and dietary supplementation showed mainly anti-excitotoxicity, anti-oxidant or anti-apoptotic properties. Interestingly, maternal preconditioning, physical exercise and environmental enrichment seem to engage the same referred mechanisms in order to protect neonatal brain against injury. This construct must be challenged by further studies to clearly define the main mechanisms responsible for neuroprotection to be explored in experimental context, as well as to test their potential in clinical settings.

Experimental neonatal hypoxia ischemia causes long lasting changes of oxidative stress parameters in the hippocampus and the spleen

Neonatal hypoxia ischemia (HI) is the main cause of mortality and morbidity in newborns. The mechanisms involved in its progression start immediately and persist for several days. Oxidative stress and inflammation are determinant factors of the severity of the final lesion. The spleen plays a major part in the inflammatory response to HI. This study assessed the temporal progression of HI-induced alterations in oxidative stress parameters in the hippocampus, the most affected brain structure, and in the spleen. HI was induced in Wistar rat pups in post-natal day 7. Production of reactive oxygen species (ROS), and the activity of the anti oxidant enzyme superoxide dismutase and catalase were assessed 24 h, 96 h and 38 days post-HI. Interestingly, both structures showed a similar pattern, with few alterations in the production of ROS species up to 96 h often combined with an increased activity of the anti oxidant enzymes. However, 38 days after the injury, ROS were at the highest in both structures, coupled with a decrease in the activity of the enzymes. Altogether, present results suggest that HI causes long lasting alterations in the hippocampus as well as in the spleen, suggesting a possible target for delayed treatments for HI.

Pregnancy swimming causes short- and long-term neuroprotection against hypoxia-ischemia in very immature rats

BackgroundHypoxia-ischemia (HI) is a major cause of neurological damage in preterm newborn. Swimming during pregnancy alters the offspring's brain development. We tested the effects of swimming during pregnancy in the very immature rat brain.MethodsFemale Wistar rats (n=12) were assigned to the sedentary (SE, n=6) or the swimming (SW, n=6) group. From gestational day 0 (GD0) to GD21 the rats in the SW group were made to swim for 20 min/day. HI on postnatal day (PND) 3 rats caused sensorimotor and cognitive impairments. Animals were distributed into SE sham (SESH), sedentary HIP3 (SEHI), swimming sham (SWSH), and swimming HIP3 (SWHI) groups. At PND4 and PND5, Na⁺/K⁺-ATPase activity and brain-derived neurotrophic factor (BDNF) levels were assessed. During lactation and adulthood, neurological reflexes, sensorimotor, anxiety-related, and cognitive evaluations were made, followed by histological assessment at PND60.ResultsAt early stages, swimming caused an increase in hippocampal BDNF levels and in the maintenance of Na⁺/K⁺-ATPase function in the SWHI group. The SWHI group showed smaller lesions and the preservation of white matter tracts. SEHI animals showed a delay in reflex maturation, which was reverted in the SWHI group. HIP3 induced spatial memory deficits and hypomyelination in SEHI rats, which was reverted in the SWHI group.ConclusionSwimming during pregnancy neuroprotected the brains against HI in very immature neonatal rats.

Homage to the ‘H’ in developmental origins of health and disease

Abundant evidence exists linking maternal and paternal environments from pericopconception through the postnatal period to later risk to offspring diseases. This concept was first articulated by the late Sir David Barker and as such coined the Barker Hypothesis. The term was then mutated to Fetal Origins of Adult Disease and finally broadened to developmental origins of adult health and disease (DOHaD) in recognition that the perinatal environment can shape both health and disease in resulting offspring. Developmental exposure to various factors, including stress, obesity, caloric-rich diets and environmental chemicals can lead to detrimental offspring health outcomes. However, less attention has been paid to date on measures that parents can take to promote the long-term health of their offspring. In essence, have we neglected to consider the ‘H’ in DOHaD? It is the ‘H’ component that should be of primary concern to expecting mothers and fathers and those seeking to have children. While it may not be possible to eliminate exposure to all pernicious factors, prevention/remediation strategies may tip the scale to health rather than disease. By understanding disruptive DOHaD mechanisms, it may also illuminate behavioral modifications that parents can adapt before fertilization and throughout the neonatal period to promote the lifelong health of their male and female offspring. Three possibilities will be explored in the current review: parental exercise, probiotic supplementation and breastfeeding in the case of mothers. The ‘H’ paradigm should be the focus going forward as a healthy start can indeed last a lifetime.

Behavioral benefits of maternal swimming are counteracted by neonatal hypoxia-ischemia in the offspring

Hypoxia-ischemia (HI) represents one of the most common causes of neonatal encephalopathy. The central nervous system injury comprises several mechanisms, including inflammatory, excitotoxicity, and redox homeostasis unbalance leading to cell death and cognitive impairment. Exercise during pregnancy is a potential therapeutic tool due to benefits offered to mother and fetus. Swimming during pregnancy elicits a strong metabolic programming in the offspring's brain, evidenced by increased antioxidant enzymes, mitochondrial biogenesis, and neurogenesis. This article aims to evaluate whether the benefits of maternal exercise are able to prevent behavioral brain injury caused by neonatal HI. Female adult Wistar rats swam before and during pregnancy (30min/day, 5 days/week, 4 weeks). At 7(th) day after birth, the offspring was submitted to HI protocol and, in adulthood (60(th) day), it performed the behavioral tests. It was observed an increase in motor activity in the open field test in HI-rats, which was not prevented by maternal exercise. The rats subjected to maternal swimming presented an improved long-term memory in the object recognition task, which was totally reversed by neonatal HI encephalopathy. BDNF brain levels were not altered; suggesting that HI or maternal exercise effects were BDNF-independent. In summary, our data suggest a beneficial long-term effect of maternal swimming, despite not being robust enough to protect from HI injury.