Background: The induction of angiogenesis and maintain the integrity of the blood brain barrier (BBB) after stroke may enhance neurorestorative processes. Panaxatriol Saponins (PTS), extracted from traditional Chinese herb Panaxnotoginseng, could noticeably prevent BBB disruption and promote angiogenesis in rodent stroke model.
Methods: Middle cerebral artery occlusion (MCAO) model were applied to mimic acute stroke in vivo. Ischemic infarct volume and neurological functions were evaluated through 2,3,5-triphenyltetrazolium chloride (TTC) staining and Longa Scores (LS) respectively. The micro-PET scan was adopted to assess cerebral perfusion; evans blue extravasation assay was used to test BBB permeability; real time PCR and Western blot were used to evaluate the level of vascular growth factors, pro-inflammation factors, the components of Sonic hedgehog (Shh) pathway and NF-κB pathway. Enzyme Linked Immunosorbent Assay (ELISA) was used to detect the levels of pro-inflammation factors in the brain. The capillaries density in ischemic penumbra and tight junction in BBB were measured by immunofluorescence staining.
Results: PTS treatment improved neurological function and reduced infarct volume in MCAO-rats. The result of micro-PET scan indicated that PTS could significantly enhance cerebral perfusion after MCAO operation. Treatment of PTS significantly attenuated BBB destruction. PTS could significantly increase the VEGF, Ang-1, VEGFR-2, Tie-2, CD31 and α-SMA mRNA expression at 3 d and 7 d after MCAO compared to vehicle group. Moreover, the expression levels of inflammation factors were decreased after PTS treatment. The co-immunofluorescence staining of α-SMA and Brdu with CD31 respectively showed that PTS promotes angiogenesis and endothelial cell proliferation after MCAO. Meanwhile, co-immunofluorescence staining of Claudin-5, Occludin and ZO-1 with CD31 respectively showed that PTS could protect tight junction from ischemia/reperfusion injury. PTS could also activate Shh pathway and inhibited NF-κB pathway.
Conclusions: PTS alleviated ischemic stroke injury through attenuates blood-brain barrier disruption and promotes angiogenesis. PTS could be a potential medication for combating ischemic brain injury.