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Updated: Jun 22, 2026
Neurobehavioral Assessments in a Mouse Model of Neonatal Hypoxic-ischemic Brain Injury
Published on: November 24, 2017
Different effects of anoxia and hind-limb immobilization on sensorimotor development and cell numbers in the
Simone Marcuzzo1, Márcio Ferreira Dutra, Felipe Stigger
1Programa de Pós-Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, RS, Brazil.
Insights
Early sensorimotor restriction (SR) and perinatal anoxia (PA) in rats impair sensorimotor development. SR alone reduced neurons, while PA increased glial cells in the developing brain, impacting motor skills.
Area of Science:
- Neuroscience
- Developmental Biology
- Neurodevelopmental Disorders
Background:
- Cerebral palsy (CP) involves movement and posture disorders from developmental brain insults.
- CP-like motor deficits in rats are modeled using sensorimotor restriction (SR) and/or perinatal anoxia (PA).
Purpose of the Study:
- To investigate the effects of early hind-limb SR, PA, or their combination on sensorimotor development in rats.
- To determine histological changes in the developing brain following these interventions.
Main Methods:
- Assessed developmental milestones (P3-P14) and motor skills (P31-P52) in rat pups.
- Measured cortical thickness and quantified neuronal/glial cell numbers in the somatosensory cortex (S1) at P52.
- Analyzed the impact of SR, PA, and combined SR+PA on sensorimotor and histological outcomes.
Main Results:
- SR significantly delayed postural stability and impaired motor skills, while hastening reflex development.
- PA (alone or with SR) increased glial cell counts in S1; SR alone decreased neuronal counts.
- Combined PA and SR led to increased neuronal soma size in S1; no significant differences in cortical thickness were observed.
Conclusions:
- Early sensorimotor restriction impairs developmental milestones and motor skill acquisition.
- Both sensorimotor restriction and perinatal anoxia induce S1 cortical histological alterations, potentially contributing to sensorimotor deficits observed in cerebral palsy models.
Abstract:
Cerebral palsy (CP) is a group of movement and posture disorders attributed to insults in the developing brain. In rats, CP-like motor deficits can be induced by early hind-limb sensorimotor restriction (SR; from postnatal days P2 to P28), associated or otherwise with perinatal anoxia (PA; on P0 and P1). In this study, we address the question of whether PA, early SR or a combination of both produces alterations to sensorimotor development. Developmental milestones (surface righting, cliff aversion, stability on an inclined surface, proprioceptive placing, auditory startle, eye opening) were assessed daily from P3 to P14. Motor skills (horizontal ladder and beam walking) were evaluated weekly (from P31 to P52). In addition, on P52, the thickness of the somatosensory (S1) and cerebellar cortices, and corpus callosum were measured, and the neuronal and glial cell numbers in S1 were counted. SR (with or without PA) significantly delayed the stability on an inclined surface and hastened the appearance of the placing reflex and impaired motor skills. No significant differences were found in the thickness measurements between the groups. Quantitative histology of S1 showed that PA, either alone or associated with SR, increased the number of glial cells, while SR alone reduced neuronal cell numbers. Finally, the combination of PA and SR increased the size of neuronal somata. We conclude that SR impairs the achievement of developmental milestones and motor skills. Moreover, both SR and PA induce histological alterations in the S1 cortex, which may contribute to sensorimotor deficits.
