scholarly journals Neuroprotective Effect of Salvianolic Acid A against Diabetic Peripheral Neuropathy through Modulation of Nrf2

2020 ◽  
Vol 2020 ◽  
pp. 1-22 ◽  
Author(s):  
Chunyang Xu ◽  
Biyu Hou ◽  
Ping He ◽  
Peng Ma ◽  
Xinyu Yang ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Sciatic Nerve ◽  
Mrna Expression ◽  
Mitochondrial Function ◽  
Diabetic Peripheral Neuropathy ◽  
Nuclear Translocation ◽  
Related Factor ◽  
Inflammatory Factor ◽  
Salvianolic Acid ◽  
Salvianolic Acid A

Oxidative stress has been recognized as the contributor to diabetic peripheral neuropathy (DPN). Antioxidant strategies have been most widely explored; nevertheless, whether antioxidants alone prevent DPN still remains inconclusive. In the present study, we established an in vitro DPN cell model for drug screening using Schwann RSC96 cells under high glucose (HG) stimulation, and we found that salvianolic acid A (SalA) mitigated HG-induced injury evidenced by cell viability and myelination. Mechanistically, SalA exhibited strong antioxidative effects by inhibiting 1,1-diphenyl-2-picrylhydrazyl (DPPH) and reducing reactive oxygen species (ROS), malondialdehyde (MDA), and oxidized glutathione (GSSG) content, as well as upregulating antioxidative enzyme mRNA expression. In addition, SalA significantly extenuated neuroinflammation with downregulated inflammatory factor mRNA expression. Furthermore, SalA improved the mitochondrial function of HG-injured Schwann cells by scavenging mitochondrial ROS, decreasing mitochondrial membrane potential (MMP), and enhancing ATP production, as well as upregulating oxidative phosphorylation gene expression. More importantly, we identified nuclear factor-E2-related factor 2 (Nrf2) as the upstream regulator which mediated protective effects of SalA on DPN. SalA directly bound to the Kelch domain of Kelch-like ECH-associated protein 1 (Keap1) and thus disrupted the interaction of Nrf2 and Keap1 predicted by LibDock of Discovery Studio. Additionally, SalA significantly inhibited Nrf2 promoter activity and downregulated Nrf2 mRNA expression but without affecting Nrf2 protein expression. Interestingly, SalA upregulated the nuclear Nrf2 expression and promoted Nrf2 nuclear translocation by high content screening assay, which was confirmed to be involved in its antiglucotoxicity effect by the knockdown of Nrf2 in RSC96 cells. In KK-Ay mice, we demonstrated that SalA could effectively improve the abnormal glucose and lipid metabolism and significantly protect against DPN by increasing the mechanical withdrawal threshold and sciatic nerve conduction velocity and restoring the ultrastructural impairment of the injured sciatic nerve induced by diabetes. Hence, SalA protected against DPN by antioxidative stress, attenuating neuroinflammation, and improving mitochondrial function via Nrf2. SalA may be prospective therapeutics for treating DPN.

scholarly journals Protection of Trigonelline on Experimental Diabetic Peripheral Neuropathy

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Ji-Yin Zhou ◽  
Shi-Wen Zhou
Keyword(s):  
Peripheral Neuropathy ◽  
Sciatic Nerve ◽  
Nerve Conduction ◽  
Diabetic Peripheral Neuropathy ◽  
Nerve Conduction Velocity ◽  
Diabetic Rats ◽  
Beneficial Effects ◽  
Mitogen Activated Protein ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1

The mechanisms leading to diabetic peripheral neuropathy are complex and there is no effective drug to treat it. As an active component of several traditional Chinese medicines, trigonelline has beneficial effects on diabetes with hyperlipidemia. The protective effects and the mechanism of trigonelline on diabetic peripheral neuropathy were evaluated in streptozotocin- and high-carbohydrate/high-fat diet-induced diabetic rats. Rats were divided into four groups at the end of week 2: control, diabetes, diabetes + trigonelline (40 mg/kg), and diabetes + sitagliptin (4 mg/kg). After 48-week treatment, technologies of nerve conduction, cold and hot immersion test, transmission electron microscopy, real-time PCR, and Western blotting were applied. Serum glucose, serum insulin, insulin sensitivity index, lipid parameters, body weight, sciatic nerve conduction velocity, nociception, glucagon-like peptide-1 receptor mRNA and protein, total and phosphorylated p38 mitogen-activated protein kinases protein expression, malonaldehyde content, and superoxide dismutase activity were altered in diabetic rats, and were near control levels treated with trigonelline. Slight micropathological changes existed in sciatic nerve of trigonelline-treated diabetic rats. These findings suggest that trigonelline has beneficial effects for diabetic peripheral neuropathy through glucagon-like peptide-1 receptor/p38 mitogen-activated protein kinases signaling pathway, nerve conduction velocity, antioxidant enzyme activity, improving micropathological changes of sciatic nerve and decreasing lipid peroxidation.

Liraglutide Ameliorates Lipotoxicity-Induced Oxidative Stress by Activating the NRF2 Pathway in HepG2 Cells

2020 ◽  
Vol 52 (07) ◽  
pp. 532-539 ◽  
Author(s):  
Chong-gui Zhu ◽  
Ying Luo ◽  
Hao Wang ◽  
Jun-Yi Li ◽  
Jie Yang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Antioxidant Enzymes ◽  
Mrna Expression ◽  
Hepg2 Cells ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Thiobarbituric Acid ◽  
Related Factor ◽  
Protective Effects ◽  
Alcoholic Fatty Liver

AbstractAlthough glucagon-like peptide-1 (GLP-1) analogue has been reported to suppress oxidative stress in non-alcoholic fatty liver disease (NAFLD), an effective therapeutic agent for NAFLD is currently unavailable. Therefore, in this study, we aimed to investigate the protective effects of the GLP-1 analogue liraglutide against lipotoxicity-induced oxidative stress in HepG2 cells and to elucidate the underlying mechanisms. HepG2 cells were cultured for 48 hours and treated with a free fatty acid (FFA) mixture: FFA mixture and liraglutide or FFA mixture, liraglutide, and exendin (9–39). Lipid accumulation was examined by oil red O staining. Oxidative stress was assessed by measuring the levels of intracellular reactive oxygen species using 2′,7′-dichlorofluorescein diacetate and thiobarbituric acid-reactive substances, whereas antioxidant capacity was assessed by measuring the activity of superoxide dismutase and catalase. Expression of the nuclear factor erythroid-2-related factor 2 (NRF2) gene and the genes encoding antioxidant enzymes was analyzed using quantitative RT-PCR. Cellular and nuclear NRF2 expression levels were assessed using immunofluorescence cell staining and western blotting. Liraglutide treatment reduced high fat-induced lipid formation and the levels of oxidative stress markers and increased antioxidant enzyme activity in HepG2 cells. Liraglutide treatment increased the mRNA expression of NRF2 target genes, induced NRF2 nuclear translocation, and increased nuclear NRF2 levels without altering NRF2 mRNA expression. Collectively, these results indicate that liraglutide exhibits a protective effect against lipotoxicity-induced oxidative stress, possibly via modulation of NRF2 and expression of antioxidant enzymes in liver cells.

scholarly journals Modulating molecular chaperones improves sensory fiber recovery and mitochondrial function in diabetic peripheral neuropathy

2012 ◽  
Vol 235 (1) ◽  
pp. 388-396 ◽  
Author(s):  
Michael J. Urban ◽  
Pan Pan ◽  
Kevin L. Farmer ◽  
Huiping Zhao ◽  
Brian S.J. Blagg ◽  
...  
Keyword(s):  
Peripheral Neuropathy ◽  
Mitochondrial Function ◽  
Molecular Chaperones ◽  
Diabetic Peripheral Neuropathy ◽  
Sensory Fiber
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