ROCK inhibition prevents tau hyperphosphorylation and p25/CDK5 increase after global cerebral ischemia

International audience; Rho-kinase (ROCK) is a downstream effector of RhoA, which has been associated with growth cone collapse and retraction in neurons. ROCK inhibition has been shown to protect against ischemic damage, thereby improving short-term collateral flow, inhibiting platelet aggregation, leukocyte adhesion, and preventing neuronal death. However, little is known about the long-term effects of ROCK inhibition on behavior and neuroprotection. The consequence of ROCK inhibition on ischemic rats' learning and spatial memory after 30 days of intracerebroventricular treatment was evaluated. It was found that Y27632 (ROCK inhibitor) reduced neurodegenerative markers, such as Fluoro-Jade, PHF (paired helicoidal filaments) immunoreactivity, and p25 protein levels, in the hippocampus of ischemic animals and improved learning and spatial memory tasks. However, Y27632 alone impaired sham animals' long-term memory. These findings demonstrated the beneficial impact of ROCK inhibition on tauopathy and altered p25 protein levels following global cerebral ischemia.