Autism-like behaviours with transient histone hyperacetylation in mice treated prenatally with valproic acid

Int J Neuropsychopharmacol. 2013 Feb;16(1):91-103. doi: 10.1017/S1461145711001714. Epub 2011 Nov 18.

Abstract

Maternal use of valproic acid (VPA) during pregnancy has been implicated in the aetiology of autism spectrum disorders in children, and rodents prenatally exposed to VPA showed behavioural alterations similar to those observed in humans with autism. However, the exact mechanism for VPA-induced behavioural alterations is not known. To study this point, we examined the effects of prenatal exposure to VPA and valpromide, a VPA analog lacking histone deacetylase inhibition activity, on behaviours, cortical pathology and histone acetylation levels in mice. Mice exposed to VPA at embryonic day 12.5 (E12.5), but not at E9 and E14.5, displayed social interaction deficits, anxiety-like behaviour and memory deficits at age 4-8 wk. In contrast to male mice, the social interaction deficits (a decrease in sniffing behaviour) were not observed in female mice at age 8 wk. The exposure to VPA at E12.5 decreased the number of Nissl-positive cells in the middle and lower layers of the prefrontal cortex and in the lower layers of the somatosensory cortex at age 8 wk. Furthermore, VPA exposure caused a transient increase in acetylated histone levels in the embryonic brain, followed by an increase in apoptotic cell death in the neocortex and a decrease in cell proliferation in the ganglionic eminence. In contrast, prenatal exposure to valpromide at E12.5 did not affect the behavioural, biochemical and histological parameters. Furthermore, these findings suggest that VPA-induced histone hyperacetylation plays a key role in cortical pathology and abnormal autism-like behaviours in mice.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation / drug effects
  • Animals
  • Autistic Disorder / chemically induced*
  • Autistic Disorder / metabolism*
  • Autistic Disorder / psychology
  • Cell Movement / drug effects
  • Cell Movement / physiology
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / metabolism
  • Female
  • Histones / metabolism*
  • Interpersonal Relations*
  • Male
  • Maze Learning / drug effects
  • Maze Learning / physiology
  • Mice
  • Mice, Inbred ICR
  • Pregnancy
  • Prenatal Exposure Delayed Effects / chemically induced*
  • Prenatal Exposure Delayed Effects / metabolism*
  • Prenatal Exposure Delayed Effects / psychology
  • Valproic Acid / adverse effects*

Substances

  • Histones
  • Valproic Acid