Behavioural recovery correlated with MRI in a rat experimental stroke model

Primary objective : To characterize a necrotic lesion using MRI and motor recovery using behavioural methods. Research design : Stroke model based on two steps: (1) development of a lesion using MR-imaging parameters and (2) behavioural recovery. Methods and procedures : Seventy male Sprague-Dawley rats were used. A focal lesion of the right sensorimotor cortex was induced photochemically. Main outcomes and results : The maximum volume of oedema and the lesion damage was reached by 6 hours. In the lesion area, the apparent diffusion coefficient (ADC) increased from 6 hours, then decreased from 24 hours. All animals spontaneously recovered motor function by day 10, despite the continued presence of the cortical lesion. Conclusions : The results show that this model mimics a core lesion, as well as the late phase in a human stroke episode. This model might be used for longitudinal study of the basic mechanisms of motor recovery.