Locomotor activity is a predictive test after global ischemia-reperfusion in Mongolian gerbils

The Mongolian gerbil is one of the main animal species used for the study of global ischemia, due to its specific Circle of Willis. Because of their anatomic variations, a large number of animals is needed. On account of the specific vulnerability of the hippocampus, striatum and neocortex, it is possible to evaluate the severity of the ischemic damage through an analysis of locomotor activity. The tests support the sensitvity of the experimental sample and compensate the interanimal variability.

The locomotor pattern of 30 male Mongolian gerbils was recorded before they were subjected to experimental bilateral carotid clippage for 15 minutes followed by reperfusion. A transparent 75x50x90 cm acrylic box was filmed in order to determine the total distance covered by the animals in five minutes, for three consecutive days. The locomotor activity of the animals was also examined in an open field at 24 hours and seven days after ischemia. Serum neurospecific enolase (NSE) was measured in the ischemic group and compared with that of an intact control group.

The recording for normal animals was uniformly similar (average 200 squares in periphery), in the first trial of 3 consecutive days (188+/-6.7 S.D.). After ischemia, the numbers increased to 388 (+/- 40 S.D.), indicating that they were sensitive to the ischemic episode. Seven days later they returned to basal values. Serum NSE was high in the ischemic group versus the intact control group (S=<0.001).

Locomotor activity in an open field is a useful reference as a predictive test to determine the sensitivity of experimental animals to ischemia. It is also associated to the degree of cerebral damage in global ischemia-reperfusion, and this behavior is representative of the expression of selective ischemic injury. The determination of NSE is useful as an associated parameter of ischemic injury.