Sensorimotor development of male and female rats subjected to neonatal anoxia

Abstract

Neonatal hypoxic‐ischemic encephalopathy (HIE) is one of the most important reasons for morbidity and mortality in term‐born infants. HIE impacts early somatic, neurological, and motor development including social. To illustrate the damages in the sensorimotor system, an adapted and validated model of neonatal anoxia is used. This study evaluated the sex differences in Wistar rats, neurological reflex, and motor development at the suckling period. Short‐ and long‐term impairments associated with sex differences were observed. In general, anoxic males were more affected in comparison to their control group and to anoxic females. Long‐lasting effects of the injury in adolescent rats predominately affected males. Similar to previous studies, we also found a decrease in the number of the substantia nigra cells in both sexes, compared to their control. So far, the results indicate that HIE caused neurobehavioral alterations and asymmetrical motor behavior with brain damage, possibly related to cognitive impairments previously observed at adolescence. These alterations may represent a useful endpoint for studying the efficacy of potential strategies that may improve the developmental consequences of a perinatal asphyxia insult in humans.

Neonatal Anoxia Impacts Rats’ Maternal Behavior and Offspring Development due to Ultrasonic Vocalization’s Impairment

“…Despite this knowledge, assessing sex differences in basic neuroscience and preclinical studies is relatively scarce. Previous research in our laboratory evaluated Wistar rats, considering sex differences, the ontogeny of reflexes onset, the sensorimotor development [7, 13, 14], and allodynia sensibility [16]. Nevertheless, it might be necessary not only to focus on the changes that emerge at a given chronological age across groups but to examine whether those changes emerge earlier or later as a function of the quantity or quality of mother-infant interactions [17, 18, 22, 43, 83, 84].…”

“…Our model opted to expose the pups at postpartum day 2 (P2) because it resembles the developmental stage of a 25-27-week gestation (preterm infant) [9][10][11][12]. We observed sex differences in the ontogeny of reflexes and development [7,[13][14][15] and interesting outcomes of NA in pain perception, insular damage, and increased astrocitary response [16]. Other models such as Rice-Vannucci of hypoxia-ischemia [9], hypoxia only, and preterm inflammatory have their value and are magnificently reviewed in Millar et al [1].…”

Pathophysiological aspects of neonatal anoxia and temporal expression of S100β in different brain regions

“…The outcomes of this condition were explored in our laboratory with a neonatal anoxia model adapted and validated for rats [3] The anoxic stimulus used, by being global and noninvasive, simulates the preterm baby of 6 months who experienced lack of oxygen [3,4]. The research data found with this model revealed cell death, by necrosis and apoptosis in hippocampus [5]; behavioral alterations in spatial memory [6]; in neonates' vocalization [7]; and in nociceptive responses [8]; sex-dependent sensorimotor impairments [9], as well as metabolic disturbances due to the anoxic condition [10]. Among others, these results and the prevalence of the neonatal anoxic injury in neonatal clinics claims for research exploring suitable biomarkers along with strategies to avoid or minimize its deleterious effects.…”