Salvianolic acid for injection protected cerebral ischemia/reperfusion injury by autophagy regulation via PI3K/AKT/mTOR pathway in rats

In clinical, Salvianolic Acid for Injection (SAFI) is a traditional compound preparation used to treat cerebral ischemia/reperfusion (I/R). We aimed to research protective effect and mechanism of SAFI on cerebral I/R. The middle cerebral artery occlusion/reperfusion (MCAO/R) rats and oxygen-glucose deprivation/reperfusion (OGD/R) cell were used in this research. After treated with SAFI and DL-3-n-butylphthalide (NBP), modified neurological severity score (mNSS), histopathology, regional cerebral blood flow (rCBF), cerebral infarction size and the brain water content of rats were measured. Meanwhile, superoxide dismutase (SOD), the interleukine 1-beta (IL-1β), thromboxane B2 (TXB2), malondialdehyde (MDA), 6-keto-PGF1α and brain-derived neurotrophic factor (BDNF), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) of I/R tissue were measured by the ELISA kits. For the experiment in vitro, the cell viability, LC3II, beclin-1 and phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mTOR protein levels were confirmed by western blot. The results illustrated SAFI decreased the mNSS, cerebral infarct size, brain water content, IL-1β, TXB2, MDA, IL-6 and TNF-α levels of I/R rats obviously. SAFI also up-regulated the rCBF, 6-keto-PGF1α, BDNF and SOD levels of I/R rats. The in vitro experiments showed that SAFI could promote the PC12 cell proliferation. The down-regulated LC3II and beclin-1 expression in the SAFI treated cells showed that SAFI could proper regulate autophagy for the PC12 cells in OGD/R group. Finally, the autophagy inhibition caused by SAFI on OGD/R cells were reversed by LY294002 and rapamycin (RAPA). These results suggested the PI3K/AKT/mTOR activation played an essential role on the autophagy regulation caused by SAFI.