Acute cardiotoxicity induced by doxorubicin in right ventricle is associated with increase of oxidative stress and apoptosis in rats

Doxorubicin (DOX) is one of the most effective chemotherapeutic agents, but its efficiency is seriously limited by the risk of developing cardiomyopathy. The most recognized cardiotoxic effect is left ventricular (LF) dysfunction, but MRI and echocardiography data demonstrated significant right ventricle (RV) function impairment. In order to clarify this aspect, the present study investigated the potential of DOX to induce acute RV cardiotoxicity at the same time as LV impairment. Rats were intraperitoneally (i.p.) injected with a single dose of 15 mg/kg DOX. DOX-treated rats were characterized by decreased body and heart weights, elevated levels of creatine kinase (CK-MB) and lactate dehydrogenase (LDH) activities compared to controls. Biochemical analyses on RV tissue revealed that the level of malondialdehyde (MDA) was significant increased (p<0.05) and activities of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPX) antioxidant enzymes were decreased by 13%, 27% and 18%, respectively, compared to control. Histopathogical and electron microscopic studies revealed DOX-induced damage in both ventricles and an increase of interstitial collagen fibers compared to controls (p<0.001), whereas immunohistochemical analysis showed weak and irregular desmin expression. Furthermore, mitochondrion-induced apoptotic pathways were also activated in both ventricles, as reflected by the up-regulation of Bax/Bcl-2 mRNA expression ratio (p<0.001) and increase of Bax and caspase-3 protein expression, as well as by the significant elevation of TUNEL positive nuclei, compared to controls (p<0.001). The results showed that DOX exerted RV toxic effects at the same time as those reported in the LV, which might be mediated through the mitochondrial-dependent apoptosis.

Characterization of Gd loaded chitosan-TPP nanohydrogels by a multi-technique approach combining dynamic light scattering (DLS), asymetrical flow-field-flow-fractionation (AF4) and atomic force microscopy (AFM) and design of positive contrast agents for molecular resonance imaging (MRI)

Chitosan CS-tripolyphosphate TPP/hyaluronic acid HA nanohydrogels loaded with gadolinium chelates (GdDOTA ⊂ CS-TPP/HA NGs) synthesized by ionic gelation were designed for lymph node (LN) MRI. In order to be efficiently drained to LNs, nanogels (NGs) needed to exhibit a diameter ϕ < 100 nm. For that, formulation parameters were tuned, using (i) CS of two different molecular weights (51 and 37 kDa) and (ii) variable CS/TPP ratio (2 < CS/TPP < 8). Characterization of NG size distribution by dynamic light scattering (DLS) and asymetrical flow-field-flow-fractionation (AF4) showed discrepancies since DLS diameters were consistently above 200 nm while AF4 showed individual nano-objects with ϕ < 100 nm. Such a difference could be correlated to the presence of aggregates inherent to ionic gelation. This point was clarified by atomic force microscopy (AFM) in liquid mode which highlighted the main presence of individual nano-objects in nanosuspensions. Thus, combination of DLS, AF4 and AFM provided a more precise characterization of GdDOTA ⊂ CS-TPP/HA nanohydrogels which, in turn, allowed to select formulations leading to NGs of suitable mean sizes showing good MRI efficiency and negligible toxicity.

Hepatoprotective effects of a self-micro emulsifying drug delivery system containing Silybum marianum native seed oil against experimentally induced liver injury

The main purpose of this study was to certify the effect of native silymarin oil (SM-oil) formulated in a self-microemulsifying drug delivery system (SMEDDS). The optimal formulation was 25% of SM-oil, 33.3 % of Cremophor RH40, 20% of Transcutol HP, 16.6% of Labrasol and 5% of Capryol 90. In this novel formulation the SM-oil was the active substance and the lipid part. The in vivo study examined the preventive effects of SMEDDS containing SM native seeds oil against carbon tetrachloride (CC14) induced hepatotoxicity in mice. Determination of alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels and also liver histology investigations have been done. The liver antioxidant status was determined with the concentrations of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), glutathione reductase (GR), and glutathione (GSH) hepatic lipid peroxidation was examined and expressed in terms of malondialdehyde (MDA) content. The plasma levels of AST and ALT significantly diminished by pre-treatment with 500 mg/kg and 1000 mg/kg SMEDDS. The pre-treatment with 500 mg/kg and 1000 mg/kg SMEDDS increased GSH level by about 6% respectively 24% compared to the CC14 group. Due to preventive administration of 500 mg/kg and 1000 mg/kg of SMEDDS in the intoxicated animals, MDA levels were reduced by 22% respectively 58%. Also, an insignificant rise by almost 17% and 19% in the animals treated with the both doses of SMEDDS could be noticed. It can be concluded that hepatotoxicity may be avoided by the oral application of our formulation.

Structural properties of silver doped hydroxyapatite and their biocompatibility

The aim of this study was to obtain a novel hydroxyapatite-based material with high biocompatibility. The structural properties of the samples were well characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). The X-ray diffraction studies revealed the characteristic peaks of hydroxyapatite in each sample. Other phases or impurities were not observed. The scanning electron microscopy observations suggest that the doping components have no influence on the surface morphology of the samples, which reveals a homogeneous aspect of the synthesized particles for all samples. The presence of calcium (Ca), phosphor (P), oxygen (O) and silver (Ag) in the Ag:HAp is confirmed by energy dispersive X-ray (EDAX) and X-ray Photoelectron Spectroscopy analyses. Nanocrystalline silver doped HAp stimulated viability and potentiated the activation of murine macrophages.

Identification of sds22 as an inhibitory subunit of protein phosphatase-1 in rat liver nuclei

sds22 was originally identified in yeast as a regulator of protein phosphatase-1 that is essential for the completion of mitosis. We show here that a structurally related mammalian polypeptide (41.6 kDa) is part of a 260-kDa species of protein phosphatase-1. This holoenzyme, designated PP-1N(sds22), could be immunoprecipitated with sds22 antibodies and was retained by microcystin-Sepharose. PP-1N(sds22) is a latent phosphatase, but its activity could be revealed by the proteolytic destruction of the noncatalytic subunit(s). PP-1N(sds22) accounted for only 5-10% of the total activity of PP-1 in rat liver nuclear extracts. A synthetic 22-mer peptide, corresponding to a leucine-rich repeat of sds22, specifically inhibited the catalytic subunit of PP-1, showing that at least part of the latency stems from the interaction of the sds22 repeat(s) with PP-1C.

Research on some metabolic and enzymatic modifications in experimental hypertensive myocardium

This paper presents our research on metabolic and enzymatic changes in the experimental, Isoproterenol-induced (ISO) hypertensive myocardium of rats. We analyze the effects produced by the simultaneous administration of adenosinetriphosphate (fosfobion) (FOS) and Isoproterenol on the changes in the body weight/heart weight ratio, and on the biochemical changes of cardiac metabolism. We studied the following parameters in the myocardium tissue and blood: plasmatic and tissular creatinin-phosphokinase, Na+K+ ATP-ase in the sarcolemma and the sarcoplasmic reticulum, Ca+2 ATP-ase in the mitochondrial membrane, sarcoplasmic reticulum and sarcolemma, as well as plasmatic and tissular lactate. Our data show an increase of heart weight to 939 mg, compared to 752 mg in the control group, while the heart weight/body weight ratio (mg/g), which was 3.8 in the control group, increased to 5.8 in the group to which Isoproterenol (ISO) was administered, and to 5.2 when fosfobion was associated. Investigation of myocardial metabolism has also shown the fact that under the influence of Isoproterenol, plasma creatinin-phosphokinase rises by 20%, while the association of fosfobion reduces it, in the myocardium tissue, down to 73%, in comparison with the values in the control group. Significant changes were found in the myocardium lactate that decreased by 26% under ISO influence, in comparison with normal values, and that decreased by 90% when FOS and ISO were administered together. This study produces arguments about metabolism-induced cardiac changes under the action of ISO and also contributes to the identification of ways that lead to cardiac hypertrophy. The experiment also demonstrates that the ATP-ases responsible for ion transportation across the membrane are actively involved in myocardium hypertrophy. The disturbances occurring in the investigated enzymatic systems are closed related with the myocardial metabolic ones. Fosfobion does not prevent the appearance and development of Isoproterenol-induced myocardial hypertrophy, but diminishes the increase of myocardial lactate produced by this synthesised catecholamine. At the same time, fosfobion significantly decreases the activity of Ca+2 ATP-ase in the plasmalemma and increases the activity of the Na+ - K+ ATP-ase both in the plasmalemma and in the sarcoplasmic reticulum, indirectly favouring the mechanical processes of cardiac myocytes relaxation. The study of the enzymatic activity of Na+K+ and Ca+2 ATP-ases in our experimental conditions contributes to a better understanding of the mechanisms that produce myocardial and coronary disturbances in myocardial hypertrophy.

Influence of isoproterenol-induced cardiac hypertrophy on oxydative myocardial stress

The purpose of this research has been to assess the role of lipidic peroxides, the involvement of the superoxide radical and of sulfhydrylic groups in isoproterenol-induced myocardium hypertrophy in rats. The results of our investigations point to increased values by 25% of plasma lipidic peroxides and in the myocardium and to a decrease of sulfhydrylic groups and of superoxide dismutase in the groups with myocardial hypertrophy, 15% and 10% respectively, compared to the controls. The comparative analysis of the data enabled us to infer the consequences of lipidic peroxides and of free radicals presence in excess and to assess the protector role of fosfobion- an energising compound-against the structural lesions of the myocyte.

Cock seminal plasma acid phosphatase: active site directed inactivation, crystallization and in vitro denaturation-renaturation studies

1. Seminal plasma acid phosphatase from the mini Rock cocks was purified on a Sepharose 6B column and was not homogeneous on polyacrylamide gel electrophoresis in the presence of sodium dodecylsulfate. Its stability in time was also determined. 2. In the same time, the enzyme was crystallized in both ethanol and ammonium sulfate and this is also an evidence that this acid phosphatase was obtained in an advanced grade of purification but is present in a complex with some quantities of other proteins. 3. It was inactivated by iodoacetate to a degree consistent with the modification of an active site residue. DTNB and thiosulfate also inhibited this enzyme. 4. The enzyme was sensitive to 6 M guanidinum hydrochloride which in the presence and absence of 0.25 M mercaptoethanol produces a deep loss of activity. After dialysis the activity was increased during the first 10 days up to 66.2% of the initial one. 5. In the presence of molar concentration of mercaptoethanol, the enzyme activity is deeply decreased, but it is partially restored after 120 hr when 1 microM CuCl2 is added.

Correlations between the activities of semen acid phosphatase and Ca(2+)-dependent ATPase and age in different breeds of cocks

1. The present work aims to find a biochemical criterion for evaluating the evolution of sperm according to age through the study of the ATPase activity from the spermatozoa and the acid phosphatase from the seminal plasma of cocks from three different breeds. 2. The optimal parameters of action of the cock semen acid phosphatase and the Ca(2+)-dependent ATPase from the spermatozoa were studied. 3. The substrate specificity of the semen acid phosphatase and its inhibition by tartrate, fluoride, metavanadate, molybdate and Hg2+ were also studied. 4. The two enzymes were determined from the Sussex, Golden Cornish and Plymouth Rock breeds at different ages. 5. The data lead to the conclusion that some properties of bird spermatozoa are less influenced by breed while the acid phosphatase activity, secreted in the ductus deferens is a breed characteristic.