Resveratrol, a natural phytoalexin: A therapeutic promise for metabolic disorders in streptozotocin-nicotinamide induced type 2 diabetic rats

Resveratrol, a natural phytoalexin, has demonstrated a wide varietyof biological activities, which make it a good candidate for treatment ofdiabetes mellitus. The present study was aimed to evaluate the propertiesof resveratrol (RSV) as an antidiabetic agent in streptozotocinnicotinamide(STZ-NIC) induced Type2 diabetes model. Furthermore, theantidiabetic nature of resveratrol was compared with glyclazide, an oralstandard antidiabetic drug. This study includes 40 male albino rats dividedinto 5 groups: control, control+resveratrol, diabetic, diabetic+resveratroland diabetic+ glyclazide. The antidiabetic effect of oral administration ofRSV (5mg kg/b.wt) for 45days was evidenced from the improvement inthe levels of blood glucose, glycosylated hemoglobin and the calculatedhomeostasis model assessment of insulin resistance. The significantdecrease (

In Vivo and In Vitro Studies on the Antioxidant Activity of Sea Cucumber Aqueous Extract against Isoproterenol-Induced Myocardial Injury in a Rat Model

The present study was undertaken to evaluate the cardiopreventive activity of the aqueous extract of sea cucumber body wall against isoproterenol- induced cardiac injury in rats. Isoproterenol a synthetic catecholamine and β-adrenergic agonist, which causes severe oxidative stress-induced myocardial injury. HPLC analysis of the sea cucumber aqueous extract revealed the presence of some active phenolic components with antioxidant activity, such as pyrogallol, rutin, chlorogenic acid, ascorbic acid, catechin, coumaric acid, cinnamic acid and ellagic acid. Subchronic oral administration of sea cucumber extract (14.4mg/Kg b.w.) to normal rats thrice weekly for 8 consecutive weeks did not exert any toxic side effects, whereas enhanced the cardiac reduced glutathione level and catalase activity, and in contrast reduced serum low density lipoprotein-cholesterol level. On the other hand, pretreatment of rats with the sea cucumber extract for 8 weeks before being intoxicated with 2 subcutaneous injections of isoproterenol normalized serum levels of total CK, CK-MB activity, total cholesterol, triglycerides and high-density lipoprotein-cholesterol, as well as cardiac glutathione peroxidase and catalase activities. In vitro antioxidant studies on the sea cucumber extract have shown a moderate scavenging activity for NO. radical and iron chelating activity, as well as a weak inhibition of lipid peroxidation. In addition, histopathological examination of H&E-stained myocardium sections of the left ventricle showed that pretreatment of isoproterenol-intoxicated rats with sea cucumber extract caused a substantial attenuation in the degenerative cellular changes induced by isoproterenol.Keywords: Holothuria atra extract, HPLC analysis, Isoproterenol, Biochemical studies, In vitro antioxidant studies, Histological studie

Cardioprotective activity of polysaccharopeptides extracted from pleurotus ostreatus mycelium in a doxorubicin-rat model

The present study was undertaken to investigate the possibleabatement of doxorubicin-induced cardiomyopathy in the rat bypolysaccharopeptides extracted from the culture broth of Pleurotusostreatus mycelium. It was found that polysaccharopeptides given asprotection before doxorubicin intoxication normalized the levels of serumtotal creatine kinase, aspartate aminotransferase and lactatedehydrogenase activities, in addition to malondialdehyde, reducedglutathione, as well as superoxide dismutase and catalase activities in theheart tissue. Nitric oxide and tumor necrosis factor-á concentrations werepersistently reduced in the heart tissue, while interferon-ã concentrationwas insignificantly changed, compared to controls. Light microscopicexamination of haematoxylin and eosin-stained sections of the leftventricles showed normal structure of the cardiac myocytes, except for aslight but significant decrease in their thickness, compared to controls. Inconclusion, pretreatment with mycelial polysaccharopeptides provided apotential protective effect against doxorubicin-induced oxidative stress inrats.Keywords: Pleurotus ostreatus mycelium, Polysaccharopeptides,Doxorubicin, Heart function tests, Antioxidant enzymes, Nitric oxide,Interferon-ã, Tumor necrosis factor-á, Histological studies

Wound-healing defect of CD18(−/−) mice due to a decrease in TGF-β(1) and myofibroblast differentiation

We studied the mechanisms underlying the severely impaired wound healing associated with human leukocyte-adhesion deficiency syndrome-1 (LAD1) using a murine disease model. In CD18(−/−) mice, healing of full-thickness wounds was severely delayed during granulation-tissue contraction, a phase where myofibroblasts play a major role. Interestingly, expression levels of myofibroblast markers α-smooth muscle actin and ED-A fibronectin were substantially reduced in wounds of CD18(−/−) mice, suggesting an impaired myofibroblast differentiation. TGF-β signalling was clearly involved since TGF-β(1) and TGF-β receptor type-II protein levels were decreased, while TGF-β(1) injections into wound margins fully re-established wound closure. Since, in CD18(−/−) mice, defective migration leads to a severe reduction of neutrophils in wounds, infiltrating macrophages might not phagocytose apoptotic CD18(−/−) neutrophils. Macrophages would thus be lacking their main stimulus to secrete TGF-β(1). Indeed, in neutrophil–macrophage cocultures, lack of CD18 on either cell type leads to dramatically reduced TGF-β(1) release by macrophages due to defective adhesion to, and subsequent impaired phagocytic clearance of, neutrophils. Our data demonstrates that the paracrine secretion of growth factors is essential for cellular differentiation in wound healing