Reproducible Motor Deficit Following Aortic Occlusion in a Rat Model Of Spinal Cord Ischemia

The overall goal of this procedure is to present the technique to make a spinal cord ischemia model in a rat. Demonstrating the procedure will be done by Mi-Sun Lim. The catheter placed in tail artery is used for monitoring of arterial pressure.

After completing the catheterization, advance the Fogarty catheter through the femoral artery into the descending thoracic aorta. To induce spinal cord ischemia, inflate the Fogarty catheter and drain the blood flow from the carotid artery into the external blood reservoir for controlling proximal arterial pressure. After the scheduled occlusion time, deflate the Fogarty catheter balloon, reinfuse the drained blood and remove the femur catheter.

Once the rat is anesthetized, place the rat in the operating table in the ventral position and maintain anesthesia with spontaneous respiration using a facial mask of inhaled isoflurane Make a horizontal skin incision on the right inguinal area. Using a 4.0 black silk suture, place a loose tie on both proximal and distal ends of the artery to maximize the exposure. While monitoring the arterial pressure through the tail artery, remove the catheters from the femoral and carotid arteries and close the wound with silk sutures.

Hind-limb motor function can be assessed using the motor deficit index. The motor deficit index is defined as the sum of the scores in relation with the lower extremities plus placing/stepping reflex and the maximum deficit is indicated by a score of six. At the assessment of hind-limb motor function at 24 hour after surgery, rats that underwent nine minutes of aortic occlusion showed mild and reversible motor impairment in the hind-limb.

Rats subjected to 10 minutes of aortic occlusion presented moderate motor deficit, but not complete paralysis. Rats that underwent 11 minutes of occlusion time, displayed complete and persistent paralysis. You can induce various degrees of hind-limb motor deficit by controlling the aortic occlusion time using this spinal cord ischemia model.

Once mastered, this technique can be performed within 40 minutes. Thank you for watching and good luck with your experiment.