Microglial Activation and Neurological Outcomes in a Murine Model of Cardiac Arrest

Title: Microglial Activation and Neurological Outcomes in a Murine Model of Cardiac Arrest

Journal: Neurocritical Care (2021) in press

Link: https://link.springer.com/article/10.1007/s12028-021-01253-w

Comments:

Neurological injury following successful resuscitation from sudden cardiac arrest (CA) is common. The role of microglia in post-CA injury is unclear. In this study, the authors investigated neurological deficits of mice resuscitated from a brief CA and, using confirmatory methods, determined the extent of microglial activation in this model.

KCl-induced asystolic CA model was created under anesthesia and ventilation followed by successful cardiopulmonary resuscitation. To quantify the neurological assessments, standardized neurological scoring, video motion tracking and sensory/motor testing were adopted. Further, neuronal degeneration and neuroinflammation were assessed using Fluoro-Jade C staining and Iba1 staining, respectively.

The study revealed three important discoveries. First, brief CA induced neuroinflammatory activation in central nervous system using Iba1 staining and microglial morphometric analysis. Second, motor injuries were particularly more prevalent than sensory deficits in the post-CA animals. Third, neuronal degeneration in the hippocampus was not limited to the CA1 region but was also prevalent in the dentate gyrus.

There is abundant evidence that activated microglia can be harmful to neurons. Microglia can mediate synapse loss by engulfment of synapses, secrete inflammatory factors that can injure neurons directly or via activation of neurotoxic astrocytes. Further investigation was needed to guide essential therapeutic target to improve post-CA prognosis regarding to inflammatory response.