Parental pre-conception stress status and risk for anxiety in rat offspring: specific and sexdependent maternal and paternal effects

Prenatal stressful events have long-lasting consequences on behavioral responses of offspring. While
the effects of gestational and maternal stress have been extensively studied on psychological alterations
in the progeny, little is known about effects of each parent’s pre-conception life events on emotional
responses in offspring. Here, the effect of maternal and/or paternal pre-conception stress was
investigated on anxiogenic responses of offspring. Male and female adult rats were subjected to predatory
stress (contactless exposure to a cat for 1þ1 h per day) for 50 (male, n: 12) and 15 (female, n: 24)
consecutive days; controls were not exposed. After the stress procedure, the control and stressed rats
were mated to create four types of breeding pairs: control female/control male, stressed female/control
male, control female/stressed male, and stressed female/stressed male. On postnatal days 30–31, the
offspring were tested on the elevated plus maze and plasma corticosterone concentration was measured.
Half of the pups were exposed to acute predatory stress before the elevated plus maze test. In
most subgroups, corticosterone and anxiety-like behaviors in the offspring with both or only one parent
exposed to pre-gestational stress increased compared to their control counterparts. However, under
acute stress conditions, a different sex-dependent pattern of anxiety responses emerged. The combined
effects of maternal and paternal stress were not additive. Hence, individual offspring behaviors can be
influenced by the former life stress experiences of either parent. Incorporation of genetic and epigenetic
aspects in development of neurobehavioral abnormalities and reprograming of the hypothalamicpituitary-
adrenal axis may contribute to this phenomenon.
LAY SUMMARY
Early life stress (including during pregnancy) is known to have long-lasting effects on offspring, including
emotional behaviors. Whether individual anxiety behaviors can be influenced by stress experiences
of each parent even before a pregnancy is less well-understood. Our findings from this study on rats
exposed to predator stress before mating suggest that maternal or paternal adult life events prior to
pregnancy can lead to maladaptive behavior in their offspring later in life.