Growth factor stimulated functional improvement following cortical ischemia.

摘要

The current study investigates the use of a growth factor treatment (epidermal growth factor (EGF) followed by erythropoietin (EPO)) to treat motor impairment following cortical ischemia in the rat. Treatment with EGF+EPO following ischemic damage of the primary motor cortex resulted in are-growth of tissue within the lesion site concomitant with functional motor improvements of the forepaw. Investigation of the functional improvement resulted in the finding that EGF+EPO treated rats engaged in behavioural compensation when completing a skilled forepaw task; whereas control treated rats did not. In order to understand the role of the new tissue in functional improvements intracortical microstimulation and aspiration of the new tissue was performed. Direct stimulation of the new tissue did not result in observable functional output, indicating that the new tissue is not directly responsible for functional improvement. Tissue adjacent to the lesion site, in EGF+EPO treated rats, did show significant reorganization compared to control treated rats. Thus, EGF+EPO may playa role in functional improvement by increasing cortical plasticity. Aspiration of the new tissue following functional improvement led to a delayed reinstatement of the functional deficit, alongside a shrinking of cortical forepaw representation. These data confirm that the new tissue is not directly responsible for functional improvements following cortical ischemia. Finally, EGF+EPO treatment appears to improve motor learning and increase cortical reorganization in the absence of cortical injury. Taken together, these data show that EGF+EPO may facilitate motor learning and cortical plasticity, both of which are imperative for functional recovery following injury of the motor cortex.