Ginkgo biloba extract (EGb-761) confers neuroprotection against ischemic stroke by augmenting autophagic/lysosomal signaling pathway.

Ginkgo biloba extract (EGb-761) is well-recognized to have neuroprotective properties. Meanwhile, autophagy machinery is extensively involved in the pathophysiological processes of ischemic stroke. The EGb-761 is widely used in the clinical treatment of stroke patients. However, its neuroprotective mechanisms against ischemic stroke are still not fully understood. The present study was conducted to uncover whether the pharmacological effects of EGb-761 can be executed by modulation of the autophagic/lysosomal signaling axis. A Sprague-Dawley rat model of ischemic stroke was established by middle cerebral artery occlusion (MCAO) for 90 min, followed by reperfusion. The EGb-761 was then administered to the MCAO rats once daily for a total of 7 days. Thereafter, the penumbral tissues were acquired to detect proteins involved in the autophagic/lysosomal pathway including Beclin1, LC-3, SQSTM1/p62, ubiquitin, cathepsin B, and cathepsin D by western blot and immunofluorescence, respectively. Subsequently, the therapeutic outcomes were evaluated by measuring the infarct volume, neurological deficits, and neuron survival. The results showed that the autophagic activities of Beclin1 and LC3-II in neurons were markedly promoted by 7 days of EGb-761 therapy. Meanwhile, the autophagic cargoes of insoluble p62 and ubiquitinated proteins were effectively degraded by EGb-761-augmented lysosomal activity of cathepsin B and cathepsin D. Moreover, the infarction size, neurological deficiencies, and neuron death were also substantially attenuated by EGb-761 therapy. Taken together, our study suggests that EGb-761 exerts a neuroprotective effect against ischemic stroke by promoting autophagic/lysosomal signaling in neurons at the penumbra. Thus, it might be a new therapeutic target for treating ischemic stroke.

Tanshinone IIA regulates the TGF-ß1/Smad signaling pathway to ameliorate non-alcoholic steatohepatitis-related fibrosis.

Tanshinone IIA (TIIA) is a major component extracted from the traditional herbal medicine Salvia miltiorrhiza and has been indicated to play a role in the treatment of organ fibrosis. However, the evidence supporting its antifibrotic effect is insufficient and the underlying mechanism is unclear. To investigate the therapeutic effect of TIIA on non-alcoholic steatohepatitis-related fibrosis (NASH-F), the present study used a methionine choline deficiency diet to induce NASH-F in rats, and explored the effect of TIIA on the transforming growth factor-ß1 (TGF-ß1)/Smad signaling pathway. Wistar rats were randomly divided into control, NASH-F and TIIA groups. After 8 weeks of treatment, the levels of serum markers associated with liver function and fibrosis were measured, liver fat vacuoles and inflammation were assessed by haematoxylin and eosin staining, and liver fibrosis was assessed by Masson's trichrome staining. TGF-ß1, Smad2, Smad3, Smad7 and α-smooth muscle actin (α-SMA) mRNA expression, and TGF-ß1, Smad2/3, phosphorylated (p)-Smad2/3, Smad7 and α-SMA protein levels were determined. The results revealed that TIIA could remarkably ameliorate liver fat vacuoles and inflammation in NASH-F rats, and could decrease the levels of serum aspartate aminotransferase, alanine aminotransferase, total bilirubin, total bile acid, hyaluronic acid, type Ⅳ collagen, laminin and type III collagen, while increasing the levels of total cholesterol and triglycerides; however, this was not statistically significance. TIIA markedly suppressed the increased TGF-ß1, Smad2, Smad3 and α-SMA mRNA expression levels observed in the liver of NASH-F rats, while it increased the mRNA expression level of Smad7. Similarly, TIIA suppressed the increased TGF-ß1, p-Smad2/3 and α-SMA protein levels observed in the liver of NASH-F rats, while it increased the protein expression level of Smad7 in vitro and in vivo. TIIA had no significant cytotoxic effect at 10, 20, 40 and 80 µmol/l on human LX-2 cell. In conclusion, the findings of the present study indicated that TIIA alleviated NASH-F by regulating the TGF-ß1/Smad signaling pathway. TIIA may be a useful tool in the prevention and treatment of NASH-F.