Treatment of protoscoleces with gamma radiation: Potential immunoprotective effect against experimental murine echinococcosis.

Cystic echinococcosis (CE) is one of the most important zoonotic diseases with a worldwide distribution. It is caused by the larval stage of the dog tapeworm "Echinococcus granulosussensu lato" and constitutes a major economic and public health problem in several countries. Protoscoleces are one component of this larval stage that can interact with both definitive and intermediate hosts. The aim of the present study was to investigate the potential role of using a radio-attenuated form of these protoscoleces for immunoprophylaxis against experimental murine echinococcosis. However, mice were immunized twice at 15-day intervals with gamma (γ) irradiated protoscoleces at doses of 0.4, 0.8, 1.2 and 1.4 kGy then challenged with the intact parasites. Macroscopic and histological analyses with cytokine measurements were performed in order to estimate the number and diameter of cysts, microscopic changes and cytokine profile. An improvement in protection against the challenge dose was observed with increasing dose, giving percentages of 47.7, 49, 55.23 and 70.6%, for the 0.4, 0.8, 1.2 and 1.4 kGy-groups respectively. These data suggest that immunization with radio-attenuated protoscoleces may induce satisfactory protective immunity by reducing successfully the formation of cysts, caused by challenge infection.

Subacute and subchronic methomyl exposure induced toxic effects on intestines via oxidative stress in male albino rats: biochemical and histopathological study.

The aim of the present study was to estimate the potential toxic effects of a subacute and a subchronic exposure to methomyl (MET) on some parts of the digestive system in male albino rats. Wistar rats were exposed daily by oral gavage to 4 mg/kg body weight (b.w.) of MET over 28 days in subacute experiments and to 1 mg/kg b.w. of MET for 90 consecutive days in subchronic exposure. Plasma levels of liver function indicators (ALT, AST, ALP and LDH) were significantly elevated after administration of MET to rats. MET had significant pro-oxidative effects on the intestines, as indicated by decreases in nonenzymatic (GSH) and enzymatic antioxidant (GPx, GST and CAT) parameters and significant increases in TBARS levels in both the duodenum and colon of rats. Microscopically, the duodenum and colon of rats exposed to MET showed severe pathological changes. It could be concluded that MET profoundly altered the structure and antioxidant status of intestinal rat tissue, which might lead to intestinal and digestive dysfunctions.

Circulating microparticles released during dyslipidemia may exert deleterious effects on blood vessels and endothelial function.

AIMS: To compare the bioactivity of circulating microparticles (MPs) isolated from dyslipidemic Psammomys obesus (P. obesus) fed a high-energy diet (HED) with those released from healthy P. obesus fed a normal diet (ND). METHODS: Vascular reactivity of aortic rings was evaluated by myography, after 24 h incubation in the absence or in the presence of circulating MPs isolated, by differential centrifugations, from the plasma of animals subjected to HED (MPsHED) or ND (MPsND) for 12 weeks. Human umbilical vein endothelial cells (HUVECs) were treated for 24 h with MPsHED or MPsND animals and subjected to immunofluorescence staining of caveolin-1 (cav-1), intercellular adhesion molecule-1 (ICAM-1), endothelial nitric oxide synthase (eNOS), F-actin and reactive oxygen species (ROS) detection. RESULTS: The HED exerted a distinctly pronounced hyperlipidemic effect marked by plasmatic increase of total cholesterol, low-density lipoprotein-cholesterol (LDL-C) and triglyceride (TG). Both MPsND and MPsHED induced a significant reduction of maximal relaxation induced by acetylcholine (ACh). Interestingly, MPsHED significantly decreased eNOS expression up to ~25% and increased ROS production up to ~75% on in vitro treated HUVECs. Moreover, in HUVECs, MPsHED significantly decreased cav-1 expression up to ~50% whereas significant increase of ICAM-1 expression by about 2-fold approximately was observed. CONCLUSION: Our experimental study demonstrated the dual role of MPs on vascular function by modulating endothelial cell function. Furthermore, MPs may be considered as vectors of a bioactive information contributing to inflammation and vascular damage.

Increased monocyte/neutrophil and pro-coagulant microparticle levels and overexpression of aortic endothelial caveolin-1ß in dyslipidemic sand rat, Psammomys obesus.

AIMS: To compare the effects of a high-energy diet (HED) with those of a low-energy diet (LED) on biochemical parameters, microparticle (MP) subpopulations and endothelial caveolin-1 (cav-1) protein expression in Psammomys obesus (P. obesus). METHODS: After 12weeks of feeding with either the HED or LED, fasting plasma glucose and lipid parameters were measured using an enzymatic colorimetric kit while serum insulin concentration was determined with radioimmunoassay kits. MP subpopulations and cav-1 protein expression were quantified using flow cytometry and western blot analysis, respectively. RESULTS: We observed that the HED caused a marked increase in lipid parameters, even in normoglycemic P. obesus. The total number of circulating MPs and the numbers of platelet-, leukocyte-, and erythrocyte-derived MPs were unaltered in the HED group. However, the HED induced increases in the numbers of monocytes/neutrophils and procoagulant MPs and a decrease in the endothelial MP levels. Cav-1ß protein expression and reactive oxygen species production were increased in the vascular endothelium of HED-treated P. obesus. CONCLUSION: From these findings, it is indicated that the HED exerts deleterious effects on the vascular system by increasing the monocyte/neutrophil and procoagulant MP levels, which may lead to cav-1ß protein overexpression in dyslipidemic P. obesus.