Efeitos de diferentes protocolos de estresse por separação maternal no comportamento de camundongos juvenis

Abstract

Introduction: The postnatal period is characterized by a high level of synaptic plasticity and being important for the development of the hippocampus. It is known that traumatic experiences during this period increase the incidence of psychiatric disorders in adulthood. The most used protocol to study this type of stress in an animal model is the maternal separation protocol. There are studies showing that the maternal separation protocol generates type-depressive behavior in male adolescent mice, but is not capable of generating type-anxious behavior. On the other hand, there are studies with male adolescent animals in which it was possible to observe type-anxious, but not type-depressive behavior. This inconsistency in the data may be due to the use of different maternal separation protocols, which are causing different types of stress and / or intensity of stress. Objective: To assess whether different maternal separation protocols are capable of generating type-anxious and type-depressive behaviors in male and female prepubertal animals. In addition, assess whether there is an influence of Physical Isolation and Time on the animals' behavior. Materials and Methods: Five experimental groups were used: a control group, which did not undergo the maternal separation protocol; a group that went through the separation at the same time every day with the litter brothers; a group that went through the separation at the same time every day isolated from the brood brothers; a group that underwent separation at variable time with the litter brothers and a group that underwent separation at variable time isolated from the litter brothers. Maternal separation occurred from the 2nd to the 14th day of birth, lasting 180 min / day. The behavior of the animals was evaluated from 28 ° to 31 ° postnatal. Results: The maternal separation protocols altered the locomotor behavior and generated type-anxious behavior in prepubertal male animals compared to the control group. The parameters analyzed in the females suffered less changes compared to the control group. The Isolated Variable Time protocol was responsible for the largest number of changes in behavioral parameters. We observed the influence of the hourly factor and the physical isolation factor, in addition to the interaction between both in the animals' behavior. Conclusion: Different types of stress protocol due to maternal separation have different effects on the behavior of male and female prepubertal mice. Key words: Stress; maternal separation protocol, behavior, sexual dimorphism, prepubertal.