Background: Brain-derived nerve growth factor (BDNF) is a promising effective target for the treatment of Alzheimer's disease (AD). BDNF, which has a high molecular weight, has difficulty in crossing the blood-brain barrier (BBB). The study aimed to prepare microbubbles loading brain-derived nerve growth factor (BDNF) retrovirus (MpLXSN-BDNF), to verify the characteristics of the microbubbles, and to study the therapeutic effect of the microbubbles combined with ultrasound on the opening of the blood-brain barrier in an AD rat model. Methods: 32 adult male SD rats were randomly divided into four groups: control group, ultrasound + pLXSN-EGFP microbubble group (U + MpLXSN-BDNF), ultrasound + pLXSN-BDNF microbubble group, and ultrasound + microbubble + pLXSN-BDNF virus group (U + MpLXSN-BDNF), with eight rats in each group. At the same time, the left hippocampus of rats was irradiated with low-frequency focused ultrasound guided by MRI to open the blood-brain barrier (BBB). The effects of BDNF overexpression on AD rats were evaluated behaviorally before and 1 month after the treatment. The number of acetylcholinesterase (ChAT)-positive cells and the content of acetylcholine (ACh) in brain tissues were determined by immunohistochemistry and high-performance liquid chromatography (HPLC), respectively. IF staining of synaptic spines and Western blot of synaptophysin presented herein detected synaptic density recovery. Results: Signal intensity enhancement at the BBB disruption sites could be observed on the MR images. The behavioral evaluation showed that the times of crossing the original platform in the U + MpLXSN-BDNF group increased significantly after treatment. Immunohistochemistry and HPLC revealed that the number of ChAT-positive neurons and the contents of ACh in the brain were significantly decreased in the treated groups compared with the controls. IF staining of synaptic spines and Western blot data of synaptophysin showed that the U + MpLXSN-BDNF group can recover the synaptic loss better by BDNF supplementation than the other treatment groups. Conclusion: Ultrasound combined with viral microbubbles carrying BDNF can increase the transfection efficiency of brain neurons, promote the high expression of exogenous gene BDNF, and play a therapeutic role in the AD model rats.

Our previous studies have shown that chlorogenic acid (CGA) could significantly improve acute and chronic liver injury through antioxidant and anti-inflammatory activities. However, its effect on non-alcoholic fatty liver disease (NAFLD) are not entirely clear. This study aims to explore the effect of CGA on NAFLD induced by high-fat diet (HFD) and whether it regulates the gut microbiota and Glucagon-like peptide-1 (GLP-1). NAFLD mice were established by HFD and treated with or without CGA. Serum transaminase, fasting blood glucose (FBG), blood lipids, insulin, GLP-1 and lipopolysaccharide (LPS) were detected. Liver histology was evaluated with Hematoxylin-eosin staining. Toll like receptor 4 (TLR4) signaling pathway was analyzed with western blot and inflammatory cytokines were detected with real-time PCR. The content of gut microbiota were determined with real-time PCR of the bacterial 16S rRNA gene. Expressions of intestine tight junctional protein were examined with immunohistochemistry. CGA could alleviate HFD-induced hepatic steatosis and inflammation, reduce serum transaminase, FBG and blood lipids, increase insulin sensitivity. CGA also could reverse HFD-induced activation of TLR4 signaling pathway and expression of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in liver. Meanwhile, CGA increased the content of Bifidobacterium and reduced the content of Escherichia coli in feces. Furthermore, CGA could increase the expression of tight junction proteins Occludin and zonula occludens-1 (ZO-1) in intestinal tissue. Moreover, CGA could the level of LPS and increased the level of GLP-1 in portal vein. These results indicated that CGA protected against HFD-induced hepatic steatosis and inflammation probably through its anti-inflammatory effects associated with regulation of gut microbiota and an increase of GLP-1 secretion and thus could be used as a potential drug for prevention and treatment of NAFLD.

Diabetes mellitus is a clinical syndrome characterised by hyperglycaemia; its complications lead to disability and even death. Semen Cassiae is a traditional Chinese medicine, which has anti-hypertensive, anti-hyperlipidaemia, anti-oxidation, and anti-ageing properties. Our study was designed to evaluate the action of total anthraquinones of Semen Cassiae extract (SCE) on the improvement of glucose metabolism in diabetic rats and to elucidate the underlying mechanism. First, we evaluated the effect of SCE on normal rats. Next, we observed the effect of SCE using a rat model of diabetes, which was established by feeding rats with high-energy diet for 4 weeks and a single intraperitoneal injection of streptozotocin (STZ; 30 mg/kg) 3 weeks after starting the high-energy diet. Rats in different SCE groups (administered 54, 108, and 324 mg/kg/day of SCE) and metformin group (162 mg/kg/day, positive control drug) were treated with the corresponding drugs 1 week before starting high-energy diet and treatment continued for 5 weeks; meanwhile, rats in the control group were administered the same volume of sodium carboxymethyl cellulose solution (vehicle solution). One week after STZ injection, fasting blood glucose (FBG), oral glucose tolerance (OGT), fasting serum insulin (FSI) and serum lipids were quantified. Finally, the expression of proteins in the phosphatidylinositol-3-kinase (PI3K)-Akt-AS160-glucose transporter isoform 4 (GLUT4) signalling pathway was detected by western blotting. The data indicated that the levels of FBG and serum lipids were significantly lowered, and OGT and FSI were markedly increased in diabetic rats treated with SCE (108 mg/kg/day); however, SCE did not cause hypoglycaemia in normal rats. The molecular mechanisms were explored in the skeletal muscle. SCE markedly restored the decreased translocation of GLUT4 in diabetic rats. Moreover, the protein expressions of phosphorylated-AS160 (Thr642), phosphorylated-Akt (Ser473) and PI3K were significantly increased after SCE treatment in the skeletal muscle. These results indicate that SCE exerts an anti-hyperglycaemic effect by promoting GLUT4 translocation through the activation of the PI3K-Akt-AS160 signalling pathway. Our findings suggest that treatment with SCE, containing anthraquinones, could be an effective approach to enhance diabetes therapy.