Bilateral jugular veins occlusion in mice: Clinical and histological findings

An impaired venous drainage from the brain and spinal cord as result of outflow obstruction in the extracranial venous system was considered as a possible contributing factor to the pathogenesis and clinical manifestations of neurodegenerative diseases. The aim of the study was to determine the contribution of impaired jugular veins to the status of the brain tissues insufficiently drained by extracranial veins. Thirty- eight mice were used for our experiments, 22 mice underwent to the bilateral ligation of the internal and external Jugular veins “(ligated group)”, 16 mice underwent to the same operative procedures and postoperative precautions but without jugular veins ligation ‘‘(sham-operated group)’’. Following the surgery, mice were monitored every day for the development of clinical symptoms. After 20 days and 3 months post-surgery, mice were sacrificed. Each brain was cut out sagittal to divide the two hemispheres. The samples were subjected to both histological and immunohistochemically staining using slides to define edema, inflammatory reaction, iron and fibrinogen deposit and demyelination. Of the 22 ligated group 7 showed a Grade 1 of clinical impairment. Histopathological assays showed the presence of brain edema and micro-hemorrhages. A significant higher number of positive inflammatory cells in the brains of ligated Group in comparison to sham group (p<0.05) was detected. No evidence of demyelination nor iron or fibrin deposition in Ligated group was demonstrated. In conclusion, jugular vein ligation altered cerebral hemodynamics without causing significant neurological symptoms. The outflow obstruction in the extracranial venous system in rodent models is able to elicit a mild inflammatory process.