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Diabetes mellitus (DM) is often accompanied by clinical complications such as sarcopenia. Previous studies have indicated that oxidative stress and insulin resistance (IR) are highly associated with the pathogenesis of diabetic myopathy. α‐lipoic acid (ALA), a potent biological antioxidant, exists abundantly in a variety of plants and vegetables. This study aimed to investigate the ameliorative effect of ALA on muscle atrophy in type 2 diabetic rats induced by high‐fat diet feeding (HFD) plus streptozotocin (STZ) injection. The HFD/STZ‐induced diabetic rats were orally administered 50, 100, or 200 mg/kg body weight ALA once a day for 13 weeks. The results showed that ALA at the tested concentrations significantly increased the soleus muscle mass and muscle fibers in diabetic rats. Proinflammatory cytokines, such as tumor necrosis factor (TNF)‐α, were found to decrease in both the serum and muscle of ALA‐treated diabetic rats. ALA significantly reduced the protein‐expression levels of phosphorylated c‐Jun N‐terminal kinase (pJNK)/JNK, forkhead box O3 (FOXO3), and muscle ring‐finger protein‐1 (Murf1); whereas, it enhanced the protein‐expression levels of phosphoinositide 3‐kinase (PI3K), phosphorylated protein kinase B (pAKT)/AKT, myogenin determination gene D (MyoD), the mechanistic target of rapamycin (mTOR), and myosin heavy chain (MyHC) in the soleus muscle of diabetic rats. The results from this study suggested that ALA treatment may preserve soleus muscle mass, alleviate muscle atrophy by suppressing the TNF‐α/JNK pathway, and ameliorate the PI3K/AKT pathway in HFD/STZ‐induced type 2 diabetic rats. [ABSTRACT FROM AUTHOR]

Background and objectives: This study aimed to investigate the enhancing effect of vitamin-like alpha-lipoic acid (ALA) on phagocytosis of oligomeric beta-amyloid (oAβ)1–42 in BV-2 mouse microglial cells. Methods: An in vitro model was established to investigate phagocytosis of oAβ1–42 in BV-2 cells. Transmission electron microscopy images indicated that the morphology of prepared oAβ1–42 was spherical particles. BV-2 cells treated with ALA were incubated with 5(6)-carboxyfluorescein-labeled oAβ1–42 (FAM-oAβ1–42) for 24 h, followed by flow cytometer analysis, western blotting, real-time quantitative PCR, and immunocytochemistry (ICC) analysis to assess the in vitro phagocytosis ability of oAβ1–42. Results: Alpha-lipoic acid significantly increased messenger RNA (mRNA) expression of the CD36 receptor in BV-2 cells. ICC analysis showed that ALA significantly elevated CD36 protein expression in BV-2 cells both with and without oAβ1–42 treatment. Results from the flow cytometry analysis indicated that the CD36 receptor inhibitor significantly attenuated ALA-promoted phagocytosis of FAM-oAβ1–42 in BV-2 cells. Moreover, ICC analysis revealed that ALA caused the translocation of peroxisome proliferator-activated receptor-γ (PPAR-γ), which is known to regulate the expression of CD36 mRNA in BV-2 cells. ALA also elevated both the mRNA and protein expression of cyclooxygenase-2 (COX-2), which is a key enzyme involved in the synthesis of 15-deoxy-Δ12,14-prostaglandin J2 in BV-2 cells. Conclusion: We postulated that ALA enhances oAβ1–42 phagocytosis by upregulating the COX-2/15-deoxy-Δ12,14-prostaglandin J2/PPAR-γ/CD36 pathway in BV-2 cells. Finally, future studies should be conducted with an in vivo study to confirm the findings. [ABSTRACT FROM AUTHOR]

Ruellia tuberosa L. (RTL) exhibits a wide range of phytochemical activities, for example, on treatment of diabetes mellitus (DM), in Orient. There is, however, few study regarding the effect of RTL on glycemic‐related homeostasis in type 2 DM (T2DM). We investigated the effect of RTL aqueous and ethanolic extracts on hypoglycemia in high‐fat diet (HFD)‐fed plus streptozotocin (STZ)‐induced T2DM rats, and examined the effect of RTL on glucose uptake in tumor necrosis factor‐α‐induced insulin‐resistant mouse C2C12 myoblasts, a mouse skeletal muscle cell line. The administration of 100 or 400 mg kg BW−1 day−1 of RTL aqueous or ethanolic extracts once a day for 4 weeks significantly ameliorated hyperglycemia, hyperinsulinemia, and the insulin resistance (IR) index in diabetic rats. RTL either aqueous or ethanolic extract at a concentration of 25–800 μg/ml significantly improved glucose uptake in insulin‐resistant mouse C2C12 myoblasts, indicating inhibiting the IR in skeletal muscles. These evidences suggest that RTL ameliorates hyperglycemia in HFD/STZ‐induced T2DM rats may be attributed to the alleviation of IR in skeletal muscles. Ruellia tuberosa L. (RTL) may improve glucose uptake in tumor necrosis factor‐α‐induced insulin‐resistant mouse C2C12 myoblasts. RTL aqueous or ethanolic extract once a day for 4 weeks could ameliorate hyperglycemia and insulin resistance (IR) index in high‐fat diet plus streptozotocin‐induced type 2 diabetes mellitus (T2DM) rats. RTL ameliorates hyperglycemia may be attributed to the suppression of IR in skeletal muscles, and subsequently prevent the progression of T2DM. [ABSTRACT FROM AUTHOR]

This study investigated the ameliorative effect of gallic acid (GA) on hypertriglyceridemia and fat accumulation in perirenal adipose tissues of high-fructose diet (HFD)-induced diabetic rats. The previous results showed that orally administered GA (30 mg/kg body weight) for four weeks significantly reduced the levels of plasma glucose and triglyceride (TG) in HFD rats. GA also markedly decreased the perirenal adipose tissues weight of HFD rats in present study (p < 0.05). Western blot assay indicated that GA restored expression of insulin signaling-related proteins, such as insulin receptor (IR), protein kinase C-zeta (PKC-ζ), and glucose transporter-4 (GLUT4) in the perirenal adipose tissues of HFD rats. Moreover, GA enhanced expression of glycolysis-related proteins, such as phosphofructokinase (PFK) and pyruvate kinase (PK), and increased the expression of lipolysis-related proteins, such as adipose triglyceride lipase (ATGL), which is involved in lipolysis in the perirenal adipose tissues of HFD rats. This study revealed that GA may alleviate hypertriglyceridemia and fat accumulation through enhancing glycolysis and lipolysis pathways in perirenal adipose tissues of HFD rats. These findings also suggest the potential of GA in preventing the progression of diabetes mellitus (DM) complications. [ABSTRACT FROM AUTHOR]

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