Insulin Treatment Forces Arteriogenesis in Diabetes Mellitus by Upregulation of the Early Growth Response-1 (Egr-1) Pathway in Mice.

The process of arteriogenesis is severely compromised in patients with diabetes mellitus (DM). Earlier studies have reported the importance of Egr-1 in promoting collateral outward remodeling. However, the role of Egr-1 in the presence of DM in outward vessel remodeling was not studied. We hypothesized that Egr-1 expression may be compromised in DM which may lead to impaired collateral vessel growth. Here, we investigated the relevance of the transcription factor Egr-1 for the process of collateral artery growth in diabetic mice. Induction of arteriogenesis by femoral artery ligation resulted in an increased expression of Egr-1 on mRNA and protein level but was severely compromised in streptozotocin-induced diabetic mice. Diabetes mellitus mice showed a significantly reduced expression of Egr-1 endothelial downstream genes Intercellular Adhesion Molecule-1 (ICAM-1) and urokinase Plasminogen Activator (uPA), relevant for extravasation of leukocytes which promote arteriogenesis. Fluorescent-activated cell sorting analyses confirmed reduced leukocyte recruitment. Diabetes mellitus mice showed a reduced expression of the proliferation marker Ki-67 in growing collaterals whose luminal diameters were also reduced. The Splicing Factor-1 (SF-1), which is critical for smooth muscle cell proliferation and phenotype switch, was found to be elevated in collaterals of DM mice. Treatment of DM mice with insulin normalized the expression of Egr-1 and its downstream targets and restored leukocyte recruitment. SF-1 expression and the diameter of growing collaterals were normalized by insulin treatment as well. In summary, our results showed that Egr-1 signaling was impaired in DM mice; however, it can be rescued by insulin treatment.

Acute and sub-acute oral toxicity assessment of the hydroalcoholic extract of Withania somnifera roots in Wistar rats.

Withania somnifera is a widely used medicinal plant for several disorders. Toxicity studies on Withania somnifera are not available. Acute and sub-acute oral toxicities of Withania somnifera root extract in Wistar rats were evaluated in the present study. In the acute toxicity study, WSR extract was administered to five rats at 2000 mg/kg, once orally and were observed for 14 days. No toxic signs/mortality were observed. In the sub-acute study, WSR extract was administered once daily for 28 days to rats at 500, 1000 and 2000 mg/kg, orally. No toxic signs/mortality were observed. There were no significant changes (P < 0.05) in the body weights, organ weights and haemato-biochemical parameters in any of the dose levels. No treatment related gross/histopathological lesions were observed. The present investigation demonstrated that the no observed adverse effect level was 2000 mg/kg body weight per day of hydroalcoholic extract of W. somnifera in rats and hence may be considered as non-toxic.

Terminalia arjuna's antioxidant effect in isolated perfused kidney.

Standardization of induction of oxidative stress with Fenton mixture (FM) in isolated perfused rat kidney and the antioxidant effect of Terminalia arjuna bark in the isolated oxidatively stressed rat kidney has been evaluated. Six groups each containing eight isolated perfused rat kidneys were used for the present study and the oxidative stress was induced by perfusing the isolated kidneys with FM. The antioxidant effect of Terminalia arjuna at the dose of 250 and 500 mg/kg was evaluated in oxidative stress induced isolated kidneys. A significant (P<0.05) increase in lipid peroxidation, gluatamate pyruvate transaminase, glutamate oxaloacetate transaminase were observed in oxidative stress induced isolated kidney. On perfusion with extract, the oxidative stress was decreased with increasing in antioxidants while the marker enzymes were found to maintain the normal level. It was concluded from the present study that hydroalcholic extract of Terminalia arjuna bark at the dose of 250 and 500 mg/kg showed significant antioxidant potential in isolated perfused rat kidneys.