Activity of glial cells in the spinal cord and the hippocampus after sciatic nerve injury in rats

摘要

The effects of acute stress over microglial dependent neuroinflammations in hippocampal structures, and its effects on emotional and spatial memory consolidation Microglial cells are the main regulatory cells inside the brain, in charge of maintaining environmental homeostasis and defense. Stressful conditions lead to an increased microglial neuroinflam- mation and phagocytosis. Under uncontrollable stress, microglial cells tend to dysregulate and accelerate their inflammatory and cytotoxic processes in the hippocampus leading to long term memory impairment and the development of stress-related dis- eases. In this paper, we present evidence of how inescapable stress increases levels of pro-inflammatory microglia and emo- tional and memory consolidation in the Carioca high and low freezing animal models (CHF and CLF) developed in the labora- tory of neuroscience of PUC-Rio, Brazil. These animals present respectively high and low vulnerability to develop stress related pathologies. Here, we observed that stressed CHF exhibited higher levels of pro-inflammatory microglia in the DG and CA1 in com- parison with non-stressed animals and their respective controls. High neuroinflammation was related with poor performance in the spatial memory task, but also a persistent fear response during the emotional memory task. Interestingly, animals of low freezing tendencies exhibited higher microglial concentration in the hip- pocampus and had the tendency to forget. We here propose that high increased neuroinflammatory agents may be affecting mem- ory consolidation after stress in the vulnerable animals, but chronic states of neuroinflammation are also causing cognitive impair- ments in the non-vulnerable strain.