The Kinetics of Intestinal Permeability in a Mouse Model of Traumatic Brain Injury

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality among trauma patients. Increased intestinal permeability plays an important role in the inflammatory process that accompanies TBI, and therapies that prevent this permeability change may improve outcomes in TBI patients. Different animal models have been developed to test permeability changes, but there has been no agreement on when permeability should be tested after TBI. Here, we describe a method for creating the TBI mouse model and for measuring intestinal permeability. We also detail our permeability measurements at different time points after TBI to help guide future experimental design. The TBI is made using a controlled cortical impact model with the cortical impactor set to speed 6 m/s, depth 3 mm, dwell time 0.2 s, and tip size 3 mm to produce a severe TBI. Permeability is measured at 2, 4, 6, and 24 hr after TBI by removing a piece of terminal ileum, tying the ends, filling the lumen with FITC-labeled dextran, and then measuring how much of the dextran moves into the surrounding solution bath over time using a fluorescent plate reader. Our results show that peak permeability occurs between 4 and 6 hr after TBI. We recommend that future experiments incorporate permeability measurements 4 to 6 hr after TBI in order to take advantage of this peak permeability. © 2020 Wiley Periodicals LLC. Basic Protocol: Mouse CCI traumatic brain injury model and intestinal permeability measurement.