The Mouse Stroke Unit Protocol with Standardized Neurological Scoring for Translational Mouse Stroke Studies

The mouse stroke model with intravascular occlusion translates well current thrombectomy and reperfusion treatments, however, it does not translate the effective clinical stroke unit routines. Here in this video, we demonstrate our proven translational mouse stroke unit concept and standardized neurological assessment scale. The first method of our protocol refers to the mouse stroke unit.

Assess animal's clinical status daily and calculate its risk certification score by summing points as shown here. Adapt frequency and intensity of support according to RSS and animal's post-stroke phase. For active nutritional support, grasp and hold the mouse gently but firm from its neck fur.

Stabilize its cheek with a middle finger and slide the middle finger towards the mouse's nose against its cheek and hold position. Place the tip of the syringe between its teeth towards the interior side of its cheek. Give approximately 40 or 50 microliters of gel food each time.

Return the mouse gently to the cage and repeat feeding after one to two minutes. Next, the focal component of the Experimental Stroke Scale is demonstrated. Start with test one for forelimb paresis.

Raise the mouse gently from its tail base and examine the forelimbs. Score zero for symmetric forward extension and mobility of forelimbs. Score one for mild flexion and reduced movement of contralesional limb.

Score two for mild flexion of the contralesional limb. Score three for adherence of the contralesional limb to the trunk, and score four for plegic limb with no limb or body movement. Now assess the hindlimb paresis.

Continue holding the mouse by its tail base as per test one. Examine the hind limbs, score zero for symmetric extension and movement of the hindlimbs. Score one for hindlimb asymmetry with significantly decreased movement and asymmetric position of the contralesional hindlimb.

Continue holding the mouse by its tail base to assess its trunk symmetry. Score zero for normal symmetric trunk flexion to both sides and no persistent trunk flexion over 30 degrees to the vertical axis. Score one for marked trunk flexion over 30 degrees to the vertical axis with contralesional predominance.

Now test for circling behavior. Place the mouse gently on a flat surface and leave it to move freely for at least one minute. Observe its movement pattern.

Score zero when the mouse moves fast and linearly. Score one for tendency to turn to one side but not in close circles. Score two for closed inconstant circles to one side.

Score three for constant close circles to one side and score four for pivoting, swaying, or no movement at all. Now test for body symmetry. Continue from test four and let the mouse move freely on the flat surface.

Observe its nose to tail axis. Score zero for normal posture, elevated trunk from the bench and straight tail. Score one for slight asymmetry when the body bends slightly to one side and the tail is distally bent.

Score two for moderate asymmetry when the body leans or bends to the contralesional side and the tail is proximally bent. Score three for prominent asymmetry when the body is bent, one side lies on the bench and the tail is clearly bent. And score four for extreme asymmetry when the body is bent and one side constantly lies on the bench.

Now for test six, continue from test five and observe its gait. Check for gait motor deficits. Score zero for normal gait when the limbs are flexible, symmetric, and quick.

Score one for stiff, inflexible, and slower gait without limping. Score two for clear limping with asymmetric movements. Score three for trembling, drifting, or falling after a gentle push.

Score four for no spontaneous walk. Now test for compulsory circling. Hold the mouse by its tail base and elevate it slightly from the surface so that it walks on its forelimbs.

Observe its movement. Score zero for normal linear movement. Score one for tendency to turn to one side.

Score two when the mouse circles to one side at complete closed circles. Score three when it pivots and its movement is sluggish. And score four when the mouse does not advance and the front part of the trunk lies on the bench.

Here we describe how to execute the posture test. Place the mouse on your palm as shown in the video and gently swing it backwards and forwards. Note how the mouse retains its upright position and balances against lateral forces, its body does not contact the palm or fingers.

Footage of different scores of that test is not helpful as its scoring heavily relies on detecting swift and subtle movements of the mouse that are felt by the hand and visual cues are not sufficient for scoring. We describe each score in the form of text for your convenience. Now assess the forelimb placing.

Hold the mouse from its back or from its tail base and direct it towards the beam as a target to reach. Observe for symmetric reach out. Then once it grabs the beam, pull it gently away and observe for symmetric release of the forelimbs.

Score zero for symmetric reach out and release. Score one for any asymmetry. Now test for sensorimotor deficit of the forelimbs.

Hold the mouse by its back as demonstrated and stimulate the forepaws successively with a fine tip. Score zero for normal prompt grasping movements. Score one for absent or clearly delayed grasping of the contralesional forepaw.

Next, test its beam walking. Place the mouse on the beam with its nose-tail axis parallel to it and allow it to balance or walk on the beam. Observe balance, limb paresis, and falls.

Always keep your hand below the animal in case it falls off. Score zero when the mouse balances with steady posture and walks towards one side of the beam. Score one when it grasps the side of the beam and does not walk on it.

Be aware that it may need some time to balance still on the beam. Score two when one limb falls off the beam. Score three when two limbs fall off the beam.

Score four when the mouse attempts to balance on the beam but falls off after 40 seconds. Be aware that in this test the mouse should be observed for up to 60 seconds. Score five when there is a fall that occurs between 20 and 40 seconds.

And score six when it makes no attempt to balance or hang on the beam. Assess whisker sensation. Place the mouse on an open benchtop and successfully stimulate its whiskers with a thin long tip cotton swab.

Coming from a blind angle, observe its turning response. Score zero for normal quick turning upon bilateral stimulation. Score one for slower contralesional response.

Score two for absent contralesional response. Score three for absent contralesional and slower ipsilesional response. And score four for bilateral absent response.

Test for climbing ability. Place the mouse in the center of a rubber coated surface at the 45 degree angle and observe its response while it tries to climb. Score zero when the mouse climbs quickly to the top of the surface.

Score one when it climbs with strain and limb weakness is present. Score two when it holds on to slope and does not slips nor climbs. Score three when it slides down the slope despite effort to prevent fall.

And score four when it slides with no effort to prevent fall. The mouse stroke unit protocol has reproducibly supported the survival of mice following the filamentous middle cerebral artery occlusion, maintaining a survival rate of 80%The focal ESS excels in detecting neurologic deficits, capturing recovery, and maintaining sensitivity for up to six months post-stroke. Complementary to the focal ESS, you can use a ladder-rung test to detect and quantify both fore and hindlimb weakness for up to six months.