Effects of angiotensin-(1-7) on oxidative stress and functional changes of isolated rat hearts induced by ischemia-reperfusion / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of angiotensin (Ang)-(1-7) on oxidative stress and functional changes in isolated rat hearts with myocardial ischemia-reperfusion (IR) injury.</p><p><b>METHODS</b>IR injury was induced in isolated rat hearts with the Langendorff' apparatus. The left ventricular systolic pressure (LVSP) of the rat heart was measured using a pressure transducer. Malondialdehyde (MDA) level and superoxide dismutase (SOD) activity in the myocardium were detected using commercial kits.</p><p><b>RESULTS</b>Myocardial ischemia (15 min) and reperfusion (30 min) significantly increased myocardial levels of MDA, and reduced the SOD activity and LVSP (P<0.05). Pretreatment with Ang-(1-7) at 1.0 nmol/L 30 min before ischemia obviously inhibited IR-induced MDA increment and lowering of SOD activity and LVSP. Pretreatment of the rats with intraperitoneal injection of 5 mg/kg indomethacin 1 h before isolation of the heart markedly antagonized the effect of Ang-(1-7) on MDA production, SOD activity and LVSP.</p><p><b>CONCLUSION</b>Angiotensin-(1-7) can inhibit IR injury-induced oxidative stress and decrease in cardiac contractile function in isolated rat hearts. The mechanism underlying the effect of Ang-(1-7) may be associated with increased secretion of prostaglandin.</p>

Study on the preparation of resveratrol chitosan nanoparticles with free amino groups on the surface / 中国中药杂志

<p><b>OBJECTIVE</b>To prepare resveratrol chitosan nanoparticles with free amine groups on the surface so as to conjugate ligands, which will actively target to special tissues or organs.</p><p><b>METHOD</b>The chitosan nanoparticles with free amine on the surface was prepared by sodium chloride precipitation. Nanoparticles with different solidification degrees were studied on turbidity, in vitro release, encapsulation efficiency, drug loading and diameter.</p><p><b>RESULT</b>The turbidity of nanoparticles with various solidification degrees decreased at different rates after ultrasonic or water bath heating treatment. All nanoparticles mentioned above obviously shew sustained release. The rate of release was slowed down with the increase of solidification agents. Solidification had no obvious effects on the encapsulation efficiency and drug loading. The diameter of chitosan nanoparticles with 200 microL solidification agents was 487 nm. The polydispersion was 0.144.</p><p><b>CONCLUSION</b>The diameter of the prepared nanoparticles was relatively small. The amine on the surface was free, which offered the possibility of designing the acive target drug delivery system.</p>