Exercise May Increase Oxidative Stress in the Sciatic Nerve in Streptozotocin-Induced Diabetic Rats

Mitigative effect of sodium alginate on streptozotocin (STZ)-induced diabetic neuropathy through regulation of redox status and miR-146a in the rat sciatic nerve

Diabetic peripheral neuropathy (DPN) is a significant complication of diabetes with limited effective therapeutic options. Sodium alginate (SA), a natural polysaccharide from brown algae, has demonstrated health benefits, however, whether it can treat streptozotocin (STZ)-induced DPN remains unclear. The present experiment aimed to test the preventive role of SA on STZ-induced DPN in rats and explored the possible mechanisms. The DPN rat model was established in rats by intraperitoneal injection of a single dose of 40 mg/kg b.w. STZ, and SA (200 mg/kg b.w./day) was orally administered for 28 days after type 2 diabetes mellitus (T2DM) induction. The obtained findings revealed that STZ significantly increased serum levels of FBG, HOMA-IR, TC, TG, VLDL-C, and LDL-C, while decreased serum insulin, incretin GLP-1, HDL-C, and lipase activity. In the sciatic nerves, STZ significantly increased proinflammatory cytokine levels (IL-1β, IL-6, and TNF-α), caspase-3 (a pro-apoptotic protein), markers of oxidative stress (MDA and NO), and AGEs. In parallel, STZ induced a significant decline in the activities of enzymatic antioxidants, viz., SOD, CAT, and GPx, and non-enzymatic GSH. These changes were accompanied by a low expression of miR-146a in the sciatic nerves of DPN rats. Except for HOMA-IR, SA treatment to STZ injected rats significantly improved these parameters and helped to rescue the neurological morphology of the sciatic nerve fibers. In conclusion, SA mitigated experimental DPN, and this might be due to its ability to suppress hyperglycemic-hyperlipidemic effects, counteract the overactivation of inflammatory molecules, increase miR-146a expression, modulate oxidative dysregulation, and reduce cell apoptosis.

Network Pharmacology Combined With Metabolomics Reveals the Mechanism of Yangxuerongjin Pill Against Type 2 Diabetic Peripheral Neuropathy in Rats

Purpose

This study aims to explore the mechanism of Yangxuerongjin pill (YXRJP) in the treatment of diabetic peripheral neuropathy (DPN) by network pharmacology and metabolomics technology combined with animal experiments, and to provide scientific basis for the treatment of DPN.

Methods

In this study, network pharmacology analysis was applied to identify the active compounds, core targets and signal pathways, which might be responsible for the effect of DPN. The DPN model was established by high-fat diet combined with streptozotocin (STZ) injection, and the rats were given administration for 12 weeks. The body weight, thermal withdrawal latency (TWL), sciatic motor nerve conduction velocity (MNCV), biochemical indexes, pathological sections of sciatic nerve, oxidative stress factors and the expression levels of neuroprotection-related proteins were detected. Metabolomics technology was used to analyze the potential biomarkers and potential metabolic pathways in DPN treated with YXRJP.

Results

The results of network pharmacology showed that YXRJP could treat DPN through baicalin, β-sitosterol, 7-methoxy-2-methylisoflavone, aloe-emodin and luteolin on insulin resistance, Toll-like receptor (TLR), tumor necrosis factor (TNF) and other signaling pathways. YXRJP can prolong the TWL, increase the MNCV of the sciatic nerve, alleviate the injury of the sciatic nerve, reduce the levels of triglyceride (TG), improve the expression of Insulin-like growth factor 1 (IGF-1) protein in the sciatic nerve, and reduce the expression of protein kinase B (AKT) protein. Metabolomics results showed that the potential metabolic pathways of YXRJP in the treatment of DPN mainly involved amino acid metabolism such as arginine, alanine, aspartic acid, lipid metabolism and nucleotide metabolism.

Conclusion

YXRJP can effectively improve the symptoms of DPN rats and reduce nerve damage. The effects are mainly related to reducing oxidative stress injury, promoting the expression of neuroprotection-related proteins, reducing the expression of inflammation-related proteins, and affecting amino acid metabolism, lipid metabolism, and nucleotide metabolism pathways. Our findings revealed that YXRJP has a good therapeutic potential for DPN, which provides a reference for further studies on YXRJP.

Moderate aerobic training counterbalances the deleterious effect of undernutrition on oxidative balance and mitochondrial markers

The state of Maternal Protein Malnutrition (MPM) is associated with several deleterious effects, including inflammatory processes and dysregulation in oxidative balance, which can promote neurodegeneration. On the other hand, it is known that aerobic exercise can promote systemic health benefits, combating numerous chronic diseases. Therefore, we evaluate the effect of aerobic exercise training (AET) on indicators of mitochondrial bioenergetics, oxidative balance, endoplasmic reticulum stress, and neurotrophic factor in the prefrontal cortex of malnourished juvenile Wistar rats. Pregnant Wistar rats were fed with a diet containing 17% or 8% casein during pregnancy and lactation. At 30 days of life, male offspring were divided into 4 groups: Low-Protein Control (LS), Low-Protein Trained (LT), Normoprotein Control (NS), and Normoprotein Trained (NT). The trained groups performed an AET for 4 weeks, 5 days a week, 1 h a day per session. At 60 days of life, the animals were sacrificed and the skeletal muscle, and prefrontal cortex (PFC) were removed to evaluate the oxidative metabolism markers and gene expression of ATF-6, GRP78, PERK and BDNF. Our results showed that MPM impairs oxidative metabolism associated with higher oxidative and reticulum stress. However, AET restored the levels of indicators of mitochondrial bioenergetics, in addition to promoting resilience to cellular stress. AET at moderate intensity for 4 weeks in young Wistar rats can act as a non-pharmacological intervention in fighting against the deleterious effects of a protein-restricted maternal diet.