Background and aims Preterm birth is associated with an increased risk of brain injury, smaller brain volume and cognitive deficits. To gain insight into how premature birth affects brain development in a pig model of preterm birth, we evaluated the growth of the neocortex and cerebellum using designed based stereology.
Methods Piglets born preterm or at term (postconceptional age (PA) 106 and 118, respectively) were euthanized on postnatal day 0, 5 or 26 (n = 1–22). The left cerebral and cerebellar hemipheres were fixed in formalin, embedded in agar, and sectioned coronally. The grey and white matter volumes were estimated using the Cavalieri method. Data were analysed by ANCOVA including PA, postnatal age, weight, litter, and gender as covariates.
Results Cerebral and cerebellar grey and white matter volumes increased significantly with PA and postnanal age (p < 0.05). Interestingly, the cerebral white matter volume increased by 127% during the last 12 days of fetal life (p < 0.001) and by 37% (p < 0.001) from birth to postnatal day 26 in term piglets. The preterm piglets had smaller cerebral white matter and cerebellar grey and white matter volumes compared to term piglets of same postnatal age (p < 0.05).
Conclusions The large increase in white matter volume during the last 12 days of fetal life suggests that this is a very sensitive period for brain growth in the piglet. These data are in agreement with human studies and thus supports the use of the preterm pig as a model for brain development in premature human infants.