Objective: To research the effects of moschus, borneol, styrax and benzoinum on the structure and function of blood brain barrier in cerebral ischemia-reperfusion injury model rats.
Method: Focal middle cerebral artery occlusion (MCAO) was introduced as an in vivo ischemic model in rats. After 2 h MCAO, nylon suture was pulled up 1 cm to give blood reperfusion. After 22 h reperfusion, all animals were decapitated. The ultramicrostructure of blood brain barrier of ischemia hemisphere side in fronto-parietal cortex region by transmission electron microscope, and the content of VEGF and MMP-9 in ischemia side brain tissue were measured by ELISA.
Result: In model and solvent group rats, the capillary endothelium cells, astro-glial cells and nerve cells in ischemia hemisphere side in fronto-parietal region were emerged in different degree compared with sham-operated groups, which exhibited tight junction between endothelial cells being opened, basal lamina being dissolved, and permeability increasing, and cellularedema. In borneol (0.2 g x kg(-1)) group rats, the structure of three kinds of cells were nearly normal, which tight junction structure was clear, rough endoplasmic reticulum and polyribosome could be found in cytoplasm. In moschus (66.6 mg x kg(-1)) group rats, the structure of capillary endothelium cells and astrocytes were nearly normal as well as the basal lamina, but the electrons in neurons was maldistribution. In styrax (1.332 g x kg(-1)) group rats, astrocytes were nearly normal, while capillary endothelial cells and neurons exhibited oedema in different degrees. And the basal lamina was discontinuous, augmentation of cell spaces in endothelial cells increased the permeability, some endoplasmic reticulum broadened and ribosome ablated. In benzoinum (1.0 g x kg(-1)) group rats, oedema of capillary endothelial cells and astrocytes was significant, basal lamina broke. Meanwhile endoplasmic reticulum broadened as vacuole, the number of ribosome in rough endoplasmic reticulum decreased, crista mitochondriales in some neurons disappeared as vacuole which hint oedema happened. Results also showed that borneol decrease the level of VEGF in ischemia side brain tissue significantly, while has little influence on the level of MMP-9. Moschus showed the tendency to decrease the level of VEGF and MMP-9 in ischemia side brain tissue.
Conclusion: Aromatic resuscitation drugs showed the protection effect on blood brain barrier in cerebral ischemia-reperfusion injury rats, which the protection effect of moschus and borneol were better than that of styrax and benzoinum. The mechanism of protection effect maybe related to decrease the level of VEGF and MMP-9.