Anti-angiogenesis and anti-inflammatory effects of Moringa oleifera leaf extract in the early stages of streptozotocin-induced diabetic nephropathy in rats

Objective:To investigate the effect of Moringa oleifera leaf extract on angiogenesis and inflammatory process in a rat model of streptozotocin-induced diabetic nephropathy.Methods:Four weeks after a single injection of 50 mg/kg streptozotocin,rats were treated with 100 or 200 mg/kg/day Moringa oleifera leaf extract,1 mg/kg/day dapagliflozin,or a combination of Moringa oleifera leaf extract and dapagliflozin for further eight weeks.Renal function,kidney histology,and gene expression were evaluated at the end of the experiment.Results:Renal function of diabetic rats was significantly impaired as evidenced by increased blood urea nitrogen,albuminuria,24-h proteinuria,and high creatinine clearance which indicated glomerular hyperfiltration.In addition,diabetic rats showed an increase in gene expressions of vascular endothelial growth factor-A(VEGF-A),angiopoietin-2(Ang2),the Ang2/Ang1 ratio,tumor necrosis factor-α,interleukin-1βand monocyte chemoattractant protein-1.Immunohistochemical staining demonstrated a significant increase in the density of glycoprotein CD34.Moringa oleifera leaf extract markedly improved all renal dysfunction markers and modulated the upregulated expression of angiogenic factors and inflammatory genes.Conclusions:Moringa oleifera leaf extract could suppress abnormal angiogenesis and inflammatory processes possibly by downregulating gene expression of angiogenesis factors and proinflammatory cytokines.

Anti-insulin resistant effect of ferulic acid on high fat diet-induced obese mice

Objective: To evaluate the insulin sensitivity action of ferulic acid(FA) in skeletal muscle and hypothalamus of high-fat diet(HFD)-induced obese mice. Methods: Obese mouse model was induced by HFD(45 kcal% lard fat) for 16 weeks. After 8 weeks of HFD feeding, these obese mice were orally treated with FA at doses of 25 and 50 mg/kg/day for 8 weeks. At the end of all treatments, the epididymal fat, pancreas, skeletal muscle and hypothalamus were removed for biochemical parameter and protein expression examinations. Results: FA treatment significantly decreased leptin level in fat tissue and insulin level in pancreas(P < 0.05). Interestingly, obese mice treated with FA increased the protein expressions of insulin receptor substrate-1, phosphatidylinositol 3-kinase, and phosphorylated-protein kinase B in both muscle and brain(P < 0.05). The phosphorylations of adenosine monophosphate-activated protein kinase and acetyl-CoA carboxylase in muscle, and leptin receptor protein in hypothalamus were also increased(P < 0.05). The pancreatic islets histology showed smaller size in obese mice treated with FA compared to untreated obese mice. Conclusions: These findings indicate the beneficial effect of FA in improving insulin resistance in HFD-induced obese mice. These effects are probably mediated via modulating the insulin receptor substrate/phosphatidylinositol 3-kinase/protein kinase B or adenosine monophosphate-activated protein kinase pathways.

Effect of Thunbergia laurifolia water extracts on hepatic insulin resistance in high-fat diet-induced obese mice

Objective:To examine the effect of water extract of Thunbergia laurifolia on hepatic insulin resistance in high-fat diet-induced obese mice.Methods:High-fat diet with 45 kcal%lard fat was used for obesity induction in ICR mice.The mice were fed with high-fat diet for 16 weeks,and during the last 8 weeks,they were treated with 200 mg/kg/day of water extracts from Thunbergia laurifolia leaf,stem and flower.Serum biochemistry,liver histology,and protein expression were examined after the treatment.Results:Extracts from all of the three parts of Thunbergia laurifolia significantly alleviated hyperglycemia,hyperlipidemia,hyperinsulinemia,and hyperleptinemia.The stem and flower extracts improved glucose tolerance.All of the extracts significantly reduced serum TNFαand monocyte chemoattractant protein-1 levels.Liver weight,triglyceride levels,and lipid accumulation were also decreased.Moreover,hepatic glucose-6-phosphatase level was significantly decreased,while the levels of PPARα,phosphorylated AMPK,and phosphorylated Akt were significantly increased with treatment of Thunbergia laurifolia extracts.Conclusions:Thunbergia laurifolia extracts can ameliorate hepatic insulin resistance in high-fat diet-induced obese mice by improving glucose and lipid homeostasis,which may be associated with stimulating phosphorylation of AMPK and Akt pathways.