Objective: To observe the effects of minimally invasive removal of intracerebral hematoma on perihematomal matrix metalloproteinase (MMP)-9 expressions and permeability of blood-brain barrier (BBB).
Methods: Twenty-four rabbits of 2.8-3.4 kg body weight (regardless of male and female) were selected and randomly divided into a control group and a minimally invasive group, and the model of intracranial hemorrhage (ICH) was established in the two groups by injecting fresh autologous non-anticoagulant blood into the brain basal ganglia of rabbits. The minimally invasive procedures for removal of intracranial hematoma were performed 6 hours after the model of ICH was established successfully. All the animals were killed on the first, third, and seventh days after the model of ICH was established, and the perihematomal brain tissues were extracted to observe MMP-9 expressions by immunohistochemical methods. The permeability of BBB was detected by Evans blue (EB) as a tracer.
Results: The numbers of neurons with expression of MMP-9 in perihematomal brain tissues on the first, third, and seventh days after minimally invasive removal of hematoma were 5.00±2.94, 13.75±7.89, and 8±6.98 respectively, while in model control group were 25.25±6.85, 39.01±10.68, and 23.12±5.72 respectively. Expression of MMP-9 in the minimally invasive group decreased significantly as compared with that of model control group, and a significant difference was observed. The content of EB in perihematomal brain tissues on the first, third and seventh days was 28.41±0.72, 34.04±1.48, and 26.30±0.78 μg respectively in minimally invasive group, and 31.24±1.02, 37.13±1.57, and 28.72±0.23 μg in the control group. A significant decrease in EB content in minimally invasive group was observed in the brain tissue around the hematoma as compared with that of control group, suggesting that the BBB permeability was reduced.
Conclusions: The minimally invasive procedure for removal of intracranial hematoma could decrease the MMP-9 expression and BBB permeability in perihematomal brain tissues. It might be helpful in reducing secondary brain damages after intracerebral hemorrhage.