Neuroserpin extends the time window of tPA thrombolysis in a rat model of middle cerebral artery occlusion.

Tissue-type plasminogen activator (tPA) is characterized as an effective drug for early thrombolytic therapy in acute cerebral infarction (ACI). However, tPA will increase the risk of hemorrhage if it is used beyond the treatment time window. The study aims to explore the effects of neuroserpin (NSP) on the time window of tPA thrombolysis in ACI and the underlying mechanism. The middle cerebral artery occlusion (MCAO) model was constructed in rats, which were randomly divided into six groups: sham operation group, infarction group, 1-hour thrombolysis group, 1-hour thrombolytic + NSP intervention group, 4-hour thrombolytic group, and 4-hour thrombolysis + NSP intervention group. The neurological changes in rats were evaluated by modified neurological severity scores and rota-rod test. The brain edema and cerebral infarction area were evaluated by dry-wet method and triphenyl tetrazolium chloride staining. The blood-brain barrier (BBB) integrity was examined by Evans blue method. The expressions of malondialdehyde, superoxide dismutase, and glutathione peroxidase in brain were also investigated. The expression of caspase-3 and Bcl-2 in brain tissue and apoptosis of neurons were examined by Western blot analysis and toluidine blue staining. tPA thrombolysis significantly attenuated the neurological impairment in rats with MCAO at 1 hour. Conversely, the effect of tPA thrombolysis at 4 hours after MCAO did not significantly help the recovery of neurological function. However, a combination of tPA treatment and NSP treatment at 4 hours after MCAO markedly ameliorated the neurological impairment, cerebral edema, cerebral infarction volume, BBB injury, oxidative stress products, and neuron apoptosis. NSP can probably expand the time window for tPA treatment to reduce neurological impairment in ACI.