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Background:Tanshinone IIA is a key active ingredient of danshen, which is derived from the dried root or rhizome of Salviae miltiorrhizae Bge. The tanshinone IIA has protective effects against the focal cerebral ischemic injury. However, the underlying mechanisms remain unclear.Methods:An in vitro model of cerebral ischemia was established by subjecting cultures of hippocampal neuronal cells to oxygen-glucose deprivation followed by reperfusion (OGD/R). The probes of 5-(and-6)-chloromethyl-2’,7’-dichlorodihydrofluorescein diacetate, acetyl ester (CM-H2DCFDA) and 5’,6,6’-tetrachloro-1,1’,3,3’-tetraethylbenzimidazolylcarbocyanine,iodide (JC-1) were used to determine the mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) production. Western-blot was used to detect the expression of proteins in HT-22 cells.Results:The results of cell proliferative assays showed that the tanshinone IIA attenuated OGD/R-mediated neuronal cell death, with the evidence of increased cell viability. In addition, OGD/R exposure led to increase the levels of intracellular reactive oxygen species (ROS), which were significantly suppressed by tanshinone IIA treatment. Furthermore, tanshinone IIA treatment inhibited elevations in MMP and autophagy following exposure to OGD/R. Additionally, OGD/R promoted cell death with concomitant inhibiting phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/ mammalian target of Rapamycin (mTOR) pathway, which was reversed by tanshinone IIA.Conclusion:These results suggest that the tanshinone IIA protects against OGD/R-mediated cell death in HT-22 cells, in part, due to activating PI3K/Akt/mTOR pathway.

The aims of the present study were to investigate the protective effect of tanshinone IIA on the brain and its therapeutic time window in a rat model of cerebral ischemia-reperfusion. The rat model of cerebral ischemia-reperfusion was established by suture occlusion. In an initial experiment, male Sprague-Dawley (SD) rats were randomly divided into control cerebral ischemia-reperfusion rat model, tanshinone IIA1 (TSA1), tanshinone IIA4 (TSA4), tanshinone IIA6 (TSA6) and tanshinone IIA12 (TSA12) groups (n=8 per group). The rats in the control group were given 4 ml phosphate-buffered saline (PBS) intraperitoneally following suture occlusion. The other groups were respectively treated with 25 mg/kg tanshinone IIA intraperitoneally at 1, 4, 6 and 12 h following the initiation of reperfusion and once a day for a total of three days. The grades of neurologic impairment and volume of cerebral infarction of each group were measured 72 h after suture occlusion. In another experiment, 16 male SD rats were randomly divided into a 6 h reperfusion group and a 24 h reperfusion group following drug administration. The rats in each group were further divided into a control subgroup (4 ml PBS) and a tanshinone IIA subgroup (25 mg/kg). The rats were immediately administered their respective treatments following the establishment of the model. The rats were decapitated 6 and 24 h after the initiation of reperfusion. The expression levels of cytoplasmic thioredoxin (Trx-1) and mitochondrial thioredoxin (Trx-2) in the ischemic penumbra were determined by western blot analysis. The nitric oxide (NO) levels, and total NO synthase (tNOS) and inducible NO synthase (iNOS) activities in the rat blood were measured using a reagent kit. The changes in cerebral blood flow were evaluated by Doppler imaging. The grade of neurological impairment of the TSA1 group was statistically lower than that of the other groups (P<0.05). The cerebral infarction volume results showed that the volumes of infarction in the TSA1 and TSA4 groups were lower than those in the other groups (P<0.05). Tanshinone IIA significantly increased cerebral blood flow compared with that of the control group (P<0.05). Moreover, tanshinone IIA significantly increased the expression levels of Trx-1 and Trx-2 compared with those in the control group (P<0.05). Tanshinone IIA significantly decreased the NO levels and iNOS and tNOS activities compared with those of the control group (P<0.05). However, the iNOS activity in the rats in the 6 h reperfusion group was not statistically significantly different from that of the respective control group (P>0.05). Tanshinone IIA has a protective effect on the cranial nerves when administered during the initial stages of cerebral ischemia. This protective effect is associated with an improvement of cerebral blood flow as well as an increase in anti-oxygen radical and anti-inflammatory activities.

The aim of the present study was to explore the role of suture diameter and vessel insertion position in the preparation of the middle cerebral artery occlusion (MCAO) rat model. A total of 84 Sprague-Dawley rats (weighing 250–300 g) were randomly divided to three groups: group A (type 1.0, suture diameter 0.16–0.17 mm and tip 0.21–0.22 mm); group B (type 2.0; suture diameter, 0.22–0.23 mm; tip, 0.27–0.28 mm); and group C (type 3.0; suture diameter, 0.28–0.29 mm; and tip, 0.33–0.34 mm). The animals in each group were then subdivided into two subgroups, one of which received a nylon line inserted through the external carotid artery (ECA insertion), while the other received the nylon line through the common carotid artery (CCA insertion) subsequent to a middle or lateral neck incision. The neurological deficit score was evaluated at 4, 8, 24, 48 and 72 h post-surgery. The ischemic brain tissue was stained by 2,3,5-triphenyltetrazolium chloride (TTC) to evaluate the extent of the infarct volume. The cerebral edema rate, cerebral infarction volume rate, relative standard deviation (RSD) of the cerebral infarction rate and the success rate were also assessed. The rectal temperature, PaO2, PaCO2, pH, blood pressure and blood glucose levels were controlled and did not vary between the group types. The results suggested that suture diameter and insertion route affected the infarct volume and success rate in the establishment of the suture MCAO rat model. Furthermore, the MCAO model with a 0.22–0.23 mm diameter suture and CCA insertion route provided the highest success rate in the SD rats.