Systemic inflammation combined with neonatal cerebellar haemorrhage aggravates long-term structural and functional outcomes in a mouse model

Brain Behav Immun. 2017 Nov:66:257-276. doi: 10.1016/j.bbi.2017.07.013. Epub 2017 Jul 27.

Abstract

Background: Despite the increased recognition of cerebellar injury in survivors of preterm birth, the neurodevelopmental consequences of isolated cerebellar injury have been largely unexplored and our current understanding of the functional deficits requires further attention in order to translate knowledge to best practices. Preterm infants are exposed to multiple stressors during their postnatal development including perinatal cerebellar haemorrhage (CBH) and postnatal infection, two major risk factors for neurodevelopmental impairments.

Methods: We developed a translational mouse model of CBH and/or inflammation to measure the short- and long-term outcomes in cerebellar structure and function.

Results: Mice exposed to early combined insults of CBH and early inflammatory state (EIS) have a delay in grasping acquisition, neonatal motor deficits and deficient long-term memory. CBH combined with late inflammatory state (LIS) does not induce neonatal motor problems but leads to poor fine motor function and long-term memory deficits at adulthood. Early combined insults result in poor cerebellar growth from postnatal day 15 until adulthood shown by MRI, which are reflected in diminished volumes of cerebellar structures. There are also decreases in volumes of gray matter and hippocampus. Cerebellar microgliosis appears 24h after the combined insults and persists until postnatal day 15 in the cerebellar molecular layer and cerebellar nuclei in association with a disrupted patterning of myelin deposition, a delay of oligodendrocyte maturation and reduced white matter cerebellar volume.

Conclusions: Together, these findings reveal poor outcomes in developing brains exposed to combined cerebellar perinatal insults in association with cerebellar hypoplasia, persistence of microgliosis and alterations of cerebellar white matter maturation and growth.

Keywords: Brain development; Cerebellar haemorrhage; Inflammation; Microgliosis; Preterm; White matter alterations.

MeSH terms

  • Animals
  • Anxiety / complications
  • Behavior, Animal*
  • Cerebellar Diseases / complications
  • Cerebellar Diseases / pathology*
  • Cerebellar Diseases / physiopathology*
  • Disease Models, Animal
  • Female
  • Inflammation / complications*
  • Intracranial Hemorrhages / complications*
  • Male
  • Maze Learning
  • Mice, Inbred C57BL
  • Mice, Inbred ICR
  • Microglia / metabolism
  • Motor Activity
  • White Matter / pathology