Infant maltreatment enhances emotional reactivity to novelty and induces depressive-like behavior in juvenile rats

AILEN ALBA COLAPIETRO; JASMIN GRILLO BALBOA; MARIANELA CEOL RETAMAL; ANDREA PECILE; MERCEDES OLIVERA; MARTA ANTONELLI; MARIA EUGENIA PALLARES

BELEM

Congreso; 3 FALAN CONGRESS 2022; 2022

FALAM

Infant maltreatment enhances emotional reactivity to novelty andinduces depressive-like behavior in juvenile ratsAILEN ALBA COLAPIETRO; JAZMÍN GRILLO BALBOA; MARIANELA N. CEOL RETAMAL;ANDREA N. PECILE; MERCEDES OLIVERA; MARTA C. ANTONELLI; MARÍA EUGENIAPALLARÉS.INSTITUTO DE BIOLOGÍA CELULAR Y NEUROCIENCIAS / IBCN, CUIDAD AUTÓNOMA DEBUENOS AIRES - ARGENTINA.Infant maltreatment is a public health problem with long-term consequences on theindividual’s physical and mental health. In Argentina, 7 out of 10 infants between theages of 2 to 4 are subjected to violent methods of discipline, which include physicaland psychological aggression. Infant maltreatment predisposes individuals to developemotional disorders, including depression and anxiety, which might be mediated bydysregulation of the stress system response. Although the current evidence on thisproblem focuses mainly on adults, to date, little studies have examined the effects ofinfant maltreatment on younger individuals, and its relevance for the early onset ofstress-related disorders. In here, we assessed the impact of infant maltreatment on ratoffspring stress system immediately after finishing the maltreatment protocol, and onthe emergence of anxiety-/depressive-like behaviors at juvenile age. We used ananimal model of early life maltreatment known as the “scarcity-adversity model” (SAM)in where the mother is given insufficient bedding for nest building during postpartumday (PND) 8 to 12. During SAM protocol we tested patterns of maternal behaviortowards her pups. After finishing SAM exposure at PND 13, we analyze offspring bodyweight and adrenal glands weight. We further measured pups’ corticosterone levels inserum. From PND 24 to 28, offspring were exposed to a behavioral test battery toevaluate stress-related behaviors. Mothers exposed to SAM had enhancedfragmented and violent behavior towards their offspring than Control dams (regularbedding conditions). In PND 13 pups, SAM did not affect their body weight gain.However, both female and male SAM offspring had increased corticosterone levels inserum than control pups. At juvenile age SAM offspring of both sexes spent more timeand did a greater amount of rearing without wall (unsupported) in the Open field test,a behavior that has been associated with greater emotionality. In the Forced swimmingtest, both SAM males and females presented greater depressive-like behaviorscompared to controls, spending less time swimming and climbing and more timeimmobile. In conclusion, infant maltreatment generates stress in the offspring due tothe increase in corticosterone levels and this modifies their coping strategies whenfaced with a novel environment or an environment with no escape such as Open-fieldtest and Forced swimming test at juvenile age. These results provide us with moreinformation about emerging behaviors at an early age as a consequence of infantmaltreatment, which may be useful for the development of anticipated interventionsthat prevent the establishment of psychopathologies later in life.