Background/Aims: Renalase, a novel flavoprotein expressed in the kidney and heart, reduces renal tubular necrosis and apoptosis, which suggests that it might protect against necrosis and/or apoptosis in myocardial ischemia reperfusion injury (MIRI). The present study thus explored the effects of renalase on Sprague-Dawley (SD) rats subjected to MIRI. Methods: We used Lentivirus-mediated RNA interference (RNAi) to inhibit the renalase gene expression in the heart tissue via pericardial cavity injection. The MIRI animal modal was established by blocking the left anterior descending artery for 45mins followed by 4h of reperfusion. Real-time PCR and western blotting were used to detect renalase expression in the heart tissue. Double staining and TUNEL were used to detect the necrosis and apoptosis in the myocardial cells, respectively. Results: All rats subjected to MIRI exhibited lower levels of renalase in the heart tissue than did the sham-operated group (P<0.05, n=6). The (RNAi) group rats exhibited lower renalase levels than did the controls and also exhibited more serious necrosis (7.12±0.56% vs. 3.32±0.93%, P<0.05, n=6) and apoptosis (151.8±8.2% vs. 66.8±6.5%, P<0.05, n=6); however, pretreatment with the recombinant renalase significantly reduced myocardial cell necrosis (1.51±0.12% vs. 4.13±0.02%, P<0.05, n=6) and apoptosis (21.3±5.0% vs. 52.6±10.4%, P<0.05, n=6) relative to the control rats. Conclusions: Exogenous recombinant renalase protein reduced myocardial cell necrosis and apoptosis. Recombinant renalase protein might be a new cardiovascular drug for ischemia/IR injury.
Laser ektacytometry is a technique widely used for measuring the deformability of red blood cells (erythrocytes) in blood samples in vitro. In ektacytometer, a°ow of highly diluted suspension of erythrocytes in variable shear stress conditions is illuminated with a laser beam to obtain a di®raction pattern. The di®raction pattern provides information about the shapes (shear-induced elongations) of the cells under investigation. This paper is dedicated to developing the technique of laser ektacytometry so that it would enable one to measure the distribution of the erythrocytes in deformability. We discuss the problem of calibration of laser ektacytometer and test a novel data processing algorithm allowing to determine the parameters of the distribution of erythrocytes deformability. Experimentally, we examined 12 specimens of blood of rats under the action of 4 shear stresses. Analysis of the data shows that in conditions of a limited range of digitizing the di®raction patterns, the measurement errors for the mean deformability, deformability scatter and the skewness of erythrocytes distribution in deformability by our method are respectively 15%, 20% and 20%.
Activation of the sympathetic nervous system aggravates the course of myocardial infarction. Semax peptide moderated the degree of this activation and prevented the increase in the density of sympathetic endings in rat caudal artery in 28 days after ischemia or ischemia/reperfusion. The peptide reduced the density of α-adrenoreceptors in the caudal artery of rats with myocardial infarction. Semax produced no effect on β-adrenoreceptors in both experimental models. The experiments on isolated segments of the caudal artery revealed reduced vascular responsiveness to electrical stimulation and norepinephrine infusion in rats treated with Semax after ischemia/reperfusion injury.
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