This protocol validates a reliable, easy-to-perform and reproducible rodent model of brain diffuse axonal injury (DAI) that induces widespread white matter damage without skull fractures or contusions.
Traumatic brain injury is one of the major causes death and disability. Diffuse axonal brain injury is a widespread axonal damage develop after TBI. In this research, I would like to present our model about induction diffuse axonal brain injury based on rotational acceleration mechanism result TBI.
Select adult male Sprague-Dawley rats weighing 300 to 350 gram. Provide rat chow and water ad libitum. Perform all experiment between 6:00 AM and 12:00 PM.The device was placed on a heavy, stable laboratory table.
The device consists of the following components:a cylinder, an iron weight, a rotational mechanism consisting of a cylindrical tube, and head fixation pins. The weight is attached to a string and elevated to the height of 120 centimeters. The freely falling weight hits the bolt activating the rotational mechanism.
The rat lateral head rotation device was used to turn the head rapidly from zero to 90 degrees. After induction, diffuse axonal brain injury, rat was moved to the recovery room. F is the force applied to the animal's head in kilograms.
Capital M is the moment of the force, K for kinetic energy. Little m is the mass of the falling weight, g for gravitational acceleration, h for height in centimeters, and D is the distance between the ear pins in centimeters. For assessment of neurological deficit and grade model deficits, we used Neurological Severity Score in rats.
We evaluate mobility, hemiplegia, beam walking task, failure in beam walking task. Failure of beam balancing task wide 1.5 centimeters. Stability and beam balancing, effort on beam balance 1.5 centimeter wide and reflexes.
48 hours post-injury, all rats, injury and control group, were deeply anesthetized and transcardiacally perfused with 0.9%heparinized saline followed by 500 milliliters of 4%formaldehyde in 0.1 M phosphate buffer saline. After perfusion, decapitation was produced and the brains were immediately removed, then fixed in a 4%formaldehyde solution for 48 hours. The brains were then blocked into five millimeter coronal sections from the olfactory bulb face to the visual cortex while the cerebellum and brain stems were dissected.
Following paraffin embedding, coronal and sagittal sections were made from the thalamus. Produce the immunochemical staining of beta-amyloid precursor protein. The various groups of rats at different times are shown on the scheme.
Diffuse axonal brain injury at the beginning of the experiment. At time 48 hours, Neurological Severity Score was examined. At time 48 hours, immunochemical staining of beta-APP was performed at all two groups.
Illustrated neurological deficit 48 hours following diffuse axonal brain injury for two study groups. A Mann-Whitney test indicated that neurological deficit was significantly greater for 15 diffuse axonal brain injury rats compared to 15 naive rats at 48 hours following intervention. Representative photomicrographs revealing axonal and neuronal immunoreactivities following isolated diffuse axonal brain injury in rats 48 hours post-injury.
Smaller cellular strings are detected with beta-amyloid precursor protein. In sham group, it wasn't detected. In our work, we developed a simple, reproducible, and reliable new model for diffuse axonal brain injury based on rotational acceleration mechanism.
Such a model will enable a better understanding of pathophysiology of diffuse axonal brain injury and development of more effective treatments. Thank you very much for your attention.
