Serum exosomes of rats with hepatic ischemia-reperfusion injury induce the damage of hippocampus and cerebral cortex / 生理学报

ABSTRACT

The paper was aimed to explore the role of serum exosomes induced by hepatic ischemia/reperfusion (I/R) injury in the damage of hippocampus and cerebral cortex of rats. The male Sprague-Dawley (SD) rats were randomly divided into 4 groups sham operation group (S), hepatic I/R injury group (I/R), serum exosomes from S group treatment group (ES) and serum exosomes from I/R group treatment group (EI). In ES group and EI group, 100 μL serum exosomes from S group and I/R group were injected into the normal rats through tail vein respectively. Another three normal rats were injected intravenously with serum exosomes labeled with PKH26 red fluorescence, and then the expression of fluorescence in the brain tissues was observed by immunofluorescence microscope. The morphology and size of exosomes were observed by transmission electron microscope, the expression of exosomes markers CD63 and CD9 was detected by Western blot, and the damage of liver and brain, levels of apoptosis and oxidative stress response in hippocampus and cerebral cortex were observed by serological and histological indexes. The results showed that the exosomes were a group of round or ovoid membranous vesicles, sized in 30-100 nm. Compared with that in S group, the content of serum exosomes in I/R group was increased (P < 0.05). Moreover, serum exosomes could go through the blood-brain barrier and enter the brain tissue freely through blood circulation. The index of liver function in I/R group was significantly higher than that in S group (P < 0.05). There was no significance in the degree of brain damage, apoptosis and oxidative stress in hippocampus and cerebral cortex between S group and ES group. Compared with those in S group and ES group, the serum levels of brain injury markers, apoptosis index (AI) and oxidative stress in hippocampus and cerebral cortex increased in I/R group and EI group (P < 0.05). Whereas, compared with those in I/R group, the above indicators in EI group decreased (P < 0.05). Therefore, hepatic I/R injury can lead to the damage of hippocampus and cerebral cortex, and the increased serum exosomes induced by hepatic I/R plays an important role.