Correlation of locomotor activity and brain infarction in rats with transient focal ischemia

Occlusion of middle cerebral artery (MCAo) is commonly used to generate stroke in experimental animals. Different behavioral assays have been used to evaluate the severity of lesions or recovery after treatment in this model. In this study, we examined the correlation between the size of infarction and locomotor activity after transient MCAo in adult Sprague-Dawley rats. The right middle cerebral artery was occluded for 30–90-min by ligation with a 10-O suture. At 2 days after MCAo, animals were individually placed in a 3-D infrared activity chamber for 1 h to measure their horizontal, vertical, stereotypic and rotational activity. Body asymmetry was examined using an elevated body swing test. Volume of infarction was measured by triphenyltetrazolium chloride staining. We found that there is a significant correlation between the volume of infarction and vertical movement, such as vertical activity, vertical movement number and vertical movement time. There is also a significant correlation between the infarction volume and body asymmetry. In conclusion, our data suggest that vertical locomotor activity and body asymmetry are useful behavioral indices to estimate the size of lesioning in rodents after MCAo.