Limits...
Complex pattern of interaction between in utero hypoxia-ischemia and intra-amniotic inflammation disrupts brain development and motor function.

Jantzie LL, Corbett CJ, Berglass J, Firl DJ, Flores J, Mannix R, Robinson S - J Neuroinflammation (2014)

Bottom Line: At postnatal day 15, myelin basic protein expression is reduced by 31% in TSHI + LPS pups compared to shams (P < 0.05).Both myelin basic protein expression (P < 0.01) and the phosphoneurofilament/neurofilament ratio, a marker of axonal dysfunction, are reduced in postnatal day 28 TSHI pups (P < 0.001).Both injuries cause significant gait deficits.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departments of Neurology and Neurosurgery, F,M, Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA. Shenandoah.Robinson@childrens.harvard.edu.

ABSTRACT

Background: Infants born preterm commonly suffer from a combination of hypoxia-ischemia (HI) and infectious perinatal inflammatory insults that lead to cerebral palsy, cognitive delay, behavioral issues and epilepsy. Using a novel rat model of combined late gestation HI and lipopolysaccharide (LPS)-induced inflammation, we tested our hypothesis that inflammation from HI and LPS differentially affects gliosis, white matter development and motor impairment during the first postnatal month.

Methods: Pregnant rats underwent laparotomy on embryonic day 18 and transient systemic HI (TSHI) and/or intra-amniotic LPS injection. Shams received laparotomy and anesthesia only. Pups were born at term. Immunohistochemistry with stereological estimates was performed to assess regional glial loads, and western blots were performed for protein expression. Erythropoietin ligand and receptor levels were quantified using quantitative PCR. Digigait analysis detected gait deficits. Statistical analysis was performed with one-way analysis of variance and post-hoc Bonferonni correction.

Results: Microglial and astroglial immunolabeling are elevated in TSHI + LPS fimbria at postnatal day 2 compared to sham (both P < 0.03). At postnatal day 15, myelin basic protein expression is reduced by 31% in TSHI + LPS pups compared to shams (P < 0.05). By postnatal day 28, white matter injury shifts from the acute injury pattern to a chronic injury pattern in TSHI pups only. Both myelin basic protein expression (P < 0.01) and the phosphoneurofilament/neurofilament ratio, a marker of axonal dysfunction, are reduced in postnatal day 28 TSHI pups (P < 0.001). Erythropoietin ligand to receptor ratios differ between brains exposed to TSHI and LPS. Gait analyses reveal that all groups (TSHI, LPS and TSHI + LPS) are ataxic with deficits in stride, paw placement, gait consistency and coordination (all P < 0.001).

Conclusions: Prenatal TSHI and TSHI + LPS lead to different patterns of injury with respect to myelination, axon integrity and gait deficits. Dual injury leads to acute alterations in glial response and cellular inflammation, while TSHI alone causes more prominent chronic white matter and axonal injury. Both injuries cause significant gait deficits. Further study will contribute to stratification of injury mechanisms in preterm infants, and guide the use of promising therapeutic interventions.

Show MeSH

Related in: MedlinePlus

Prenatal injury significantly impacts motor function in juvenile rats. Digigait analyses at postnatal day 28 demonstrate significant motor impairment and gait abnormalities in both forelimbs and hindlimbs of lipopolysaccharide (LPS; n = 13), transient systemic hypoxia-ischemia (TSHI; n = 14) and TSHI + LPS (n = 21) rats, compared to shams (n = 18). Impairment includes (A) decreased stride length, (B) increased stride variation, (C) decreased time in the propel phase, (D) decreased paw area at peak stride, consistent with toe-walking, and (E) increased stride frequency, which all culminate in (F) increased ataxia coefficients. *P < 0.05, ** P < 0.01, *** P < 0.001, versus shams. CV, Coefficient of variation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4128546&req=5

Figure 6: Prenatal injury significantly impacts motor function in juvenile rats. Digigait analyses at postnatal day 28 demonstrate significant motor impairment and gait abnormalities in both forelimbs and hindlimbs of lipopolysaccharide (LPS; n = 13), transient systemic hypoxia-ischemia (TSHI; n = 14) and TSHI + LPS (n = 21) rats, compared to shams (n = 18). Impairment includes (A) decreased stride length, (B) increased stride variation, (C) decreased time in the propel phase, (D) decreased paw area at peak stride, consistent with toe-walking, and (E) increased stride frequency, which all culminate in (F) increased ataxia coefficients. *P < 0.05, ** P < 0.01, *** P < 0.001, versus shams. CV, Coefficient of variation.

Mentions: Consistent with the clinical picture of cerebral palsy and spasticity in children suffering perinatal brain injury, LPS (n = 13), TSHI (n = 14) and TSHI + LPS (n = 21) rats showed functional gait abnormalities and postural instability, including significant impairments in stride, cadence, consistency and coordination compared to shams (n = 18; Figure 6). Cumulatively, movement of the forelimbs and hindlimbs were abnormal, and most rats with prenatal injury with all lesion types had difficulty with coordinated stepping, as indicated by the reduced stride length (Figure 6A), an increased coefficient in stride length variation (Figure 6B), stride frequency (Figure 6E) and ataxia (Figure 6F). Also, hindlimb time in the propel phase was reduced in TSHI and TSHI + LPS pups (Figure 6C). Interestingly, TSHI and TSHI + LPS pups exhibited evidence of toe walking consistent with spastic gait hallmarked by significantly decreased paw area at peak stance (Figure 6D). Similar to children with spasticity from prematurity, the hindlimbs were affected more severely than the forelimbs for most parameters, including the paw area (Figure 6D). While all injuries markedly affected the gait, the presence of TSHI, with or without LPS, produced more abnormalities. Subgroups analyses for sex did not reveal sex-specific differences in the deficits, except that females did not have decreased time in the propel phase, and males did not have decreased paw area at peak stance for any of the injury groups. Together, these gait studies in juvenile rats demonstrate that prenatal injury induces persistent gait abnormalities with similarities to the gait abnormalities found in children with spasticity from preterm birth. More importantly, these functional studies suggest that the various types of prenatal injuries result in different gait abnormalities.


Complex pattern of interaction between in utero hypoxia-ischemia and intra-amniotic inflammation disrupts brain development and motor function.

Jantzie LL, Corbett CJ, Berglass J, Firl DJ, Flores J, Mannix R, Robinson S - J Neuroinflammation (2014)

Prenatal injury significantly impacts motor function in juvenile rats. Digigait analyses at postnatal day 28 demonstrate significant motor impairment and gait abnormalities in both forelimbs and hindlimbs of lipopolysaccharide (LPS; n = 13), transient systemic hypoxia-ischemia (TSHI; n = 14) and TSHI + LPS (n = 21) rats, compared to shams (n = 18). Impairment includes (A) decreased stride length, (B) increased stride variation, (C) decreased time in the propel phase, (D) decreased paw area at peak stride, consistent with toe-walking, and (E) increased stride frequency, which all culminate in (F) increased ataxia coefficients. *P < 0.05, ** P < 0.01, *** P < 0.001, versus shams. CV, Coefficient of variation.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4128546&req=5

Figure 6: Prenatal injury significantly impacts motor function in juvenile rats. Digigait analyses at postnatal day 28 demonstrate significant motor impairment and gait abnormalities in both forelimbs and hindlimbs of lipopolysaccharide (LPS; n = 13), transient systemic hypoxia-ischemia (TSHI; n = 14) and TSHI + LPS (n = 21) rats, compared to shams (n = 18). Impairment includes (A) decreased stride length, (B) increased stride variation, (C) decreased time in the propel phase, (D) decreased paw area at peak stride, consistent with toe-walking, and (E) increased stride frequency, which all culminate in (F) increased ataxia coefficients. *P < 0.05, ** P < 0.01, *** P < 0.001, versus shams. CV, Coefficient of variation.
Mentions: Consistent with the clinical picture of cerebral palsy and spasticity in children suffering perinatal brain injury, LPS (n = 13), TSHI (n = 14) and TSHI + LPS (n = 21) rats showed functional gait abnormalities and postural instability, including significant impairments in stride, cadence, consistency and coordination compared to shams (n = 18; Figure 6). Cumulatively, movement of the forelimbs and hindlimbs were abnormal, and most rats with prenatal injury with all lesion types had difficulty with coordinated stepping, as indicated by the reduced stride length (Figure 6A), an increased coefficient in stride length variation (Figure 6B), stride frequency (Figure 6E) and ataxia (Figure 6F). Also, hindlimb time in the propel phase was reduced in TSHI and TSHI + LPS pups (Figure 6C). Interestingly, TSHI and TSHI + LPS pups exhibited evidence of toe walking consistent with spastic gait hallmarked by significantly decreased paw area at peak stance (Figure 6D). Similar to children with spasticity from prematurity, the hindlimbs were affected more severely than the forelimbs for most parameters, including the paw area (Figure 6D). While all injuries markedly affected the gait, the presence of TSHI, with or without LPS, produced more abnormalities. Subgroups analyses for sex did not reveal sex-specific differences in the deficits, except that females did not have decreased time in the propel phase, and males did not have decreased paw area at peak stance for any of the injury groups. Together, these gait studies in juvenile rats demonstrate that prenatal injury induces persistent gait abnormalities with similarities to the gait abnormalities found in children with spasticity from preterm birth. More importantly, these functional studies suggest that the various types of prenatal injuries result in different gait abnormalities.

Bottom Line: At postnatal day 15, myelin basic protein expression is reduced by 31% in TSHI + LPS pups compared to shams (P < 0.05).Both myelin basic protein expression (P < 0.01) and the phosphoneurofilament/neurofilament ratio, a marker of axonal dysfunction, are reduced in postnatal day 28 TSHI pups (P < 0.001).Both injuries cause significant gait deficits.

View Article: PubMed Central - HTML - PubMed

Affiliation: Departments of Neurology and Neurosurgery, F,M, Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA 02115, USA. Shenandoah.Robinson@childrens.harvard.edu.

ABSTRACT

Background: Infants born preterm commonly suffer from a combination of hypoxia-ischemia (HI) and infectious perinatal inflammatory insults that lead to cerebral palsy, cognitive delay, behavioral issues and epilepsy. Using a novel rat model of combined late gestation HI and lipopolysaccharide (LPS)-induced inflammation, we tested our hypothesis that inflammation from HI and LPS differentially affects gliosis, white matter development and motor impairment during the first postnatal month.

Methods: Pregnant rats underwent laparotomy on embryonic day 18 and transient systemic HI (TSHI) and/or intra-amniotic LPS injection. Shams received laparotomy and anesthesia only. Pups were born at term. Immunohistochemistry with stereological estimates was performed to assess regional glial loads, and western blots were performed for protein expression. Erythropoietin ligand and receptor levels were quantified using quantitative PCR. Digigait analysis detected gait deficits. Statistical analysis was performed with one-way analysis of variance and post-hoc Bonferonni correction.

Results: Microglial and astroglial immunolabeling are elevated in TSHI + LPS fimbria at postnatal day 2 compared to sham (both P < 0.03). At postnatal day 15, myelin basic protein expression is reduced by 31% in TSHI + LPS pups compared to shams (P < 0.05). By postnatal day 28, white matter injury shifts from the acute injury pattern to a chronic injury pattern in TSHI pups only. Both myelin basic protein expression (P < 0.01) and the phosphoneurofilament/neurofilament ratio, a marker of axonal dysfunction, are reduced in postnatal day 28 TSHI pups (P < 0.001). Erythropoietin ligand to receptor ratios differ between brains exposed to TSHI and LPS. Gait analyses reveal that all groups (TSHI, LPS and TSHI + LPS) are ataxic with deficits in stride, paw placement, gait consistency and coordination (all P < 0.001).

Conclusions: Prenatal TSHI and TSHI + LPS lead to different patterns of injury with respect to myelination, axon integrity and gait deficits. Dual injury leads to acute alterations in glial response and cellular inflammation, while TSHI alone causes more prominent chronic white matter and axonal injury. Both injuries cause significant gait deficits. Further study will contribute to stratification of injury mechanisms in preterm infants, and guide the use of promising therapeutic interventions.

Show MeSH
Related in: MedlinePlus