Oxytocin ameliorates impaired social behavior in a Chd8 haploinsufficiency mouse model of autism.

Background: Autism spectrum disorder (ASD) is characterized by the core symptoms of impaired social interactions. Increasing evidence suggests that ASD has a strong genetic link with mutations in chromodomain helicase DNA binding protein 8 (CHD8), a gene encoding a chromatin remodeler. It has previously been shown that Chd8 haplodeficient male mice manifest ASD-like behavioral characteristics such as anxiety and altered social behavior. Along with that, oxytocin (OT) is one of the main neuropeptides involved in social behavior. Administration of OT has shown improvement of social behavior in genetic animal models of ASD. The present study was undertaken to further explore behavioral abnormalities of Chd8 haplodeficient mice of both sexes, their link with OT, and possible effects of OT administration. First, we performed a battery of behavioral tests on wild-type and Chd8 ^+/∆SL female and male mice. Next, we measured plasma OT levels and finally studied the effects of intraperitoneal OT injection on observed behavioral deficits.
Results: We showed general anxiety phenotype in Chd8 ^+/∆SL mice regardless of sex, the depressive phenotype in Chd8 ^+/∆SL female mice only and bidirectional social deficit in female and male mice. We observed decreased level of OT in Chd ^+/∆SL mice, possibly driven by males. Mice injected by OT demonstrated recovery of social behavior, while reduced anxiety was observed only in male mice.
Conclusions: Here, we demonstrated that abnormal social behaviors were observed in both male and female Chd8 ^+/∆SL mice. The ability of peripheral OT administration to affect such behaviors along with altered plasma OT levels indicated a possible link between Chd8 + /∆SL and OT in the pathogenesis of ASD as well as the possible usefulness of OT as a therapeutic tool for ASD patients with CHD8 mutations.