GW4869 inhibits the release of exosomes from bone marrow mesenchymal stem cells / 中国组织工程研究

BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) and BMSCs-derived exosomes have similar functions, but the regulatory mechanism underlying the release of exosomes is still unclear. OBJECTIVE: To investigate the role of GW4869, an inhibition of neutral sphingomyelinase 2, in the release of exosomes in BMSCs and the influence of GW4869 on BMSCs proliferation. METHODS: Rat BMSCs were divided into three groups: normal control group, 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (24-hour GW4869 treatment followed by 24-hour successive culture with drug withdrawal). Cultured cells were collected to extract exosomes by ultracentrifugation. Western blot was used to detect exosome-associated proteins CD63 and tumor susceptibility gene 101 (TSG101). The concentration and size distribution of exosomes were measured using nanoparticle tracking analysis. BCA was used to test the level of total proteins in exosomes. Live cell imaging system was used to observe the influence of GW4869 on BMSCs proliferation. RESULTS AND CONCLUSION: (1) Western blot results showed that exosomes expressed marker proteins such as CD63, TSG101. (2) Findings from the nanoparticle tracking analysis confirmed that the size of released exosomes was about 114 nm. (3) Significantly reduced release of exosomes was found in the two treatment groups compared with the normal control group (P < 0.01), but there was no significant difference between 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (P > 0.05). (4) No significant difference in the proliferation of BMSCs was found among the three groups (P > 0.05). To conclude, 24-hour W4869 can inhibit the release of exosomes by BMSCs and this inhibitory effect is still sustained within 24 hours after drug withdrawal. However, GW4869 has no influence on the proliferation of BMSCs.

Effect of yiqi huoxue recipe on cardiac function and ultrastructure in regression of pressure overload-induced myocardial hypertrophy in rats / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of Yiqi Huoxue Recipe (YHR) on the cardiac function and ultrastructure during the regression of myocardial hypertrophy induced by pressure overload in rats.</p><p><b>METHODS</b>The model of myocardial hypertrophy was established by abdominal aortic banding. Eighty male Wistar rats were divided into six groups, the normal control group I (n=20), the normal control group II (n=12), the hypertension model group I (n=12), the hypertension model group II (n=12), the YHR group (n=12) and the Captopril group (n=12). The observation was carried out in the normal control group I and the hypertension model group I after 4 weeks of modeling, and the other four groups were observed after 16 weeks of modeling (12 weeks of administration). The cardiac function was measured with a multichannel biological signal analysis system, and the myocardium ultrastructure was observed by a transmission electron microscope.</p><p><b>RESULTS</b>(1) Compared with the normal control group I, the systolic blood pressure and cardiac coefficient (left ventricular weight/body weight) in the model I group was higher (P<0.05, P<0.01). (2) In the YHR group, cardiac coefficient and -dp/dt(max) were lower, left ventricular systolic pressure and +dp/dt(min) were higher when compared with the model group II and the Captopril group (P<0.05 or P<0.01). In the Captopril group, only cardiac coefficient was lower when compared with the mode group II (P<0.05). (3) Compared with the normal control group II, +dp/dt(max) was higher (P<0.01) -dp/dt(max) and isovolumetric contraction time (ICT) was lower (P<0.05, P<0.01) in both the YHR group and the Captopril group. (4) Results of the myocardium ultrastructure showed edema under myocardium plasmalemma, enlarged sarcoplasmic reticulum and T tube, and significantly enlarged intercalated disc of the cardiac muscle in the model groups. In the Captopril group, the extension of sarcoplasmic reticulum and T tube as well as the pathological changes of intercalated disc were lighter, with slight edema under the myocardium plasmalemma. In the YHR group, the expansion of the sarcoplasmic reticulum was less than in the Captopril group, part of the pathological changes of intercalated discs was slightly more severe than that in the Captopril group, the dissolution of nuclear chromatin was not found, which was similar to that of the Captopril group, and no injury of the nucleus was found, either.</p><p><b>CONCLUSION</b>YHR could reverse myocardial hypertrophy in rats with abdominal aortic banding and improve the systolic and diastolic function of the left ventricle. The ultrastructure of the myocardium such as arcoplasmic reticulum, intercalated disc, and cell nucleus in abdominal aortic banding rats could be partly reversed by the recipe.</p>

Study of correlation factors with left ventricular hypertrophy during cardiac hypertrophy induced hypertension and regression in rats / 中国应用生理学杂志

<p><b>AIM</b>To investigate the relations between left ventricular hypertrophy and systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), neuropeptide Y (NPY) during cardiac hypertrophy and regression.</p><p><b>METHODS</b>Blood pressure and heart rate were recorded with polygraph channel biologic message system. NPY in plasma and myocardium were measured with Radioimmunoassay. Correlation coefficient were calculated with SPSS software.</p><p><b>RESULTS</b>There were positive correlations between SBP, DBP, MAP, NPY in the cardiac tissue and cardiac coefficient (LVW/BW). There was no correlations between cardiac coefficient and heart rate (HR), NPY in plasma.</p><p><b>CONCLUSION</b>Hypertension is one of cardiac hypertrophy factors, SBP correlate better with LVW/ BW than DBP. SBP, DBP, MAP, NPY in cardiac tissue has correlative tendency with LVW/BW.</p>