Schisandrin B protects against myocardial ischemia/reperfusion injury via the PI3K/Akt pathway in rats.

The natural medicinal monomer, schisandrin B (Sch B), has been shown to exert cardioprotective effects; however, the underlying mechanisms of these effects remain to be fully elucidated. Therefore, the aim of the present study was to investigate whether Sch B attenuated myocardial ischemia/reperfusion (I/R) injury via the phosphoinositide 3­kinases (PI3K)/Akt signaling pathway. To confirm this, I/R models were established in rats by ligation of the left anterior descending coronary artery. A group of animals were administered with Sch B (60 mg/kg, lavage) and/or the PI3K inhibitor, LY294002 (0.3 mg/kg, intraperitoneal). Myocardial infarct size, myocardial infarct serum markers, myocardial apoptotic index and the expression of Akt were measured in each group. The results demonstrated that the administration of Sch B reduced the size of the myocardial infarct, and this effect was eliminated following LY294002 treatment. In addition, the administration of Sch B decreased the apoptotic index and the serum markers of myocardial infarction. Sch B administration also increased the expression of phosphorylated Akt, and Sch B treatment decreased the B­cell lymphoma 2 (Bcl­2)­like protein 4/Bcl­2 ratio and the expression of cleaved caspase­3. Therefore, Sch B may protect myocardial tissue from I/R injury via the PI3K/Akt signaling pathway in rats.

Salvianolic acid A protects against myocardial ischemia/reperfusion injury by reducing platelet activation and inflammation.

The aim of the present study was to investigate the protective effect of salvianolic acid A (SAA) on myocardial ischemia/reperfusion injury in rats. SAA (10 mg/kg) or Tirofiban (60 µg/kg) was administered to rats by jugular vein injection 10 min before the initiation of reperfusion. After 3 h of reperfusion, platelet aggregation was measured using an aggregometer and levels of nitric oxide (NO) were detected using an ultraviolet spectrophotometer. Serum levels of cardiac troponin T (cTnT), creatine kinase isoenzyme MB (CK-MB), p-selectin, interleukin-1ß (IL-1ß) and tumor necrosis factor-α (TNF-α) were also measured 3 and 24 h after reperfusion. Furthermore, morphology of the ischemic myocardium was histopathologically analyzed by hematoxylin and eosin staining, and the infarct area was evaluated by Evans blue and triphenyltetrazolium chloride staining. In rats subjected to reperfusion, it was observed that pretreatment with SAA significantly increased the survival rate (P<0.05), and that increased survival rate was due to a significant decrease in infarct size, as evidenced by significantly reduced serum levels of cTnT and CK-MB (P<0.05). In addition, decreases in infarct size occurred through the inhibition of platelet aggregation and inflammation associated with reperfusion-induced myocardial cell damage, as indicated by reduced serum levels of p-selectin, TNF-α, IL-1ß and NO. In conclusion, SAA was protective against myocardial ischemia/reperfusion injury in rats by serving antiplatelet and anti-inflammation roles.

Schisandrin B Prevents Hind Limb from Ischemia-Reperfusion-Induced Oxidative Stress and Inflammation via MAPK/NF-κB Pathways in Rats.

Schisandrin B (ScB), isolated from Schisandra chinensis (S. chinensis), is a traditional Chinese medicine with proven cardioprotective and neuroprotective effects. However, it is unclear whether ScB also has beneficial effects on rat hind limb ischemia/reperfusion (I/R) injury model. In this study, ScB (20 mg/kg, 40 mg/kg, and 80 mg/kg) was administered via oral gavage once daily for 5 days before the surgery. After 6 h ischemia and 24 h reperfusion of left hind limb, ScB reduced I/R induced histological changes and edema. ScB also suppressed the oxidative stress through decreasing MDA level and increasing SOD activity. Moreover, above changes were associated with downregulated TNF-α mRNA expression and reduced level of IL-1ß in plasma. Meanwhile, ScB treatment downregulated activation of p38MAPK, ERK1/2, and NF-κB in ischemic skeletal muscle. These results demonstrate that ScB treatment could prevent hind limb I/R skeletal muscle injury possibly by attenuating oxidative stress and inflammation via p38MAPK, ERK1/2, and NF-κB pathways.

Thymoquinone attenuates monocrotaline-induced pulmonary artery hypertension via inhibiting pulmonary arterial remodeling in rats.

BACKGROUND: Pulmonary artery remodeling induced by excess proliferation, migration and apoptosis resistance of pulmonary arterial smooth muscle cells (PASMCs) is a key component in pulmonary artery hypertension (PAH). Thymoquinone (TQ) triggers cancer cells apoptosis through multiple mechanisms. In addition, TQ inhibits migration of human nonsmall-cell lung cancer cells and human glioblastoma cells. OBJECTIVES: In the current study, we investigated effects of TQ on MCT-induced PAH in rats and its underlying mechanisms. METHODS: After 2weeks of monocrotaline injection (MCT, 60mg/kg), Male Sprague-Dawley rats received TQ (8mg/kg, 12mg/kg, 16mg/kg) or olive oil per day for 2weeks. Hemodynamic changes, right ventricular hypertrophy, and lung morphological features were examined 4weeks later. In addition, TUNEL, PCNA, α-SMA, Bax and Bcl-2 were detected by immunohistochemistry staining. Bax, Bcl-2, cleaved caspase-3, cleaved poly (ADP-ribose) polymerase (PARP) MMP2, MMP9 and activation of p38MAPK and NF-κB were assessed by Western blot. RESULTS: MCT-induced an increase in pulmonary blood pressure and right ventricular hypertrophy, which were attenuated by TQ treatment. TQ also blocked MCT-induced pulmonary arterial remodeling, proliferation of PASMCs, elevation of MMP2 and downregulation of ratio of Bax/Bcl-2, cleaved caspase-3 and cleaved PARP. Furthermore, TQ inhibited MCT-induced activation of p38MAPK and NF-κB. CONCLUSIONS: TQ ameliorates MCT-induced pulmonary artery hypertension by inhibiting pulmonary arterial remodeling partially via p38MAPK/NF-κB signaling pathway in rats.