Therapeutic effect and mechanism of super time window venous thrombolysis on thromboembolic middle cerebral artery occlusion in rats

ObjectiveTo investigate the effects of super time window venous thrombolysis on thrombotic middle cerebral artery occlusion in rats.

MethodsEighty rats were divided into the control group, cerebral infarction group, 4.5 h thrombolysis group and 6 h thrombolysis group according to random number method(20 rats each group).The control group rats were treated with the sham operation, and the middle cerebral artery occlusion model was established in cerebral infarction group, 4.5 h thrombolysis group and 6 h thrombolysis group.The 4.5 h thrombolysis group and 6 h thrombolysis group were intravenously treated with the recombinant tissue plasminogen activator(r-tPA) after 4.5 h and 6 h of modeling.The cerebral infarction volume, microvessel density, contents of nitric oxide(NO) and malondialdehyde(MDA), and activity of superoxide dismutase(SOD) in the cortical brain tissue were measured.

ResultsThe volume of cerebral infarction in 4.5 h thrombolytic group and 6 h thrombolytic group on the third day and seventh day was significantly lower than that in cerebral infarction group(P < 0.01).The microvessel densities in 4.5 h thrombolytic group and 6 h thrombolytic group were significantly higher than that in cerebral infarction group(P < 0.01), and which in 6 h thrombolytic group were significantly lower than that in 4.5 h thrombolytic group on the third day and seventh day(P < 0.05).The microvessel densities in 4.5 h thrombolytic group and 6 h thrombolytic group on the seventh day were significantly higher than that on the third day(P < 0.01).Compared with the cerebral infarction group, the levels of NO and MDA significantly increased, and the SOD level significantly decreased in cortical brain tissue in control group, 4.5 h thrombolysis group and 6 h thrombolysis group on the third day and seventh day(P < 0.05 to P < 0.01).The level of MDA in cortical brain tissue in 6 h thrombolysis group was higher than that in 4.5 h thrombolysis group on the third day and seventh day(P < 0.05 to P < 0.01).The level of SOD in cortical brain tissue in 6 h thrombolysis group was lower than that in 4.5 h thrombolysis group on the third day and seventh day(P < 0.05).The levels of NO in cortical brain tissue in 4.5 h thrombolysis group and 6 h thrombolysis group on the seventh day were higher than that on the third day(P < 0.05).

ConclusionsThe super time window thrombolytic therapy can reduce the infarct volume of thrombus middle cerebral artery embolization in rats, and the mechanism of which may be related to the increasing of the microvessel density, decreasing of NO and MDA contents, and increasing of SOD activity in cortical brain tissue.