Erythropoietin promotes myocardial infarction repair in mice by improving the function of Sca-1+ stem cells / 生理学报

Myocardial infarction (MI) is one of the leading causes of death in the world. With the improvement of clinical therapy, the mortality of acute MI has been significantly reduced. However, as for the long-term impact of MI on cardiac remodeling and cardiac function, there is no effective prevention and treatment measures. Erythropoietin (EPO), a glycoprotein cytokine essential to hematopoiesis, has anti-apoptotic and pro-angiogenetic effects. Studies have shown that EPO plays a protective role in cardiomyocytes in cardiovascular diseases, such as cardiac ischemia injury and heart failure. EPO has been demonstrated to protect ischemic myocardium and improve MI repair by promoting the activation of cardiac progenitor cells (CPCs). This study aimed to investigate whether EPO can promote MI repair by enhancing the activity of stem cell antigen 1 positive stem cells (Sca-1+ SCs). Darbepoetin alpha (a long-acting EPO analog, EPOanlg) was injected into the border zone of MI in adult mice. Infarct size, cardiac remodeling and performance, cardiomyocyte apoptosis and microvessel density were measured. Lin- Sca-1+ SCs were isolated from neonatal and adult mouse hearts by magnetic sorting technology, and were used to identify the colony forming ability and the effect of EPO, respectively. The results showed that, compared to MI alone, EPOanlg reduced the infarct percentage, cardiomyocyte apoptosis ratio and left ventricular (LV) chamber dilatation, improved cardiac performance, and increased the numbers of coronary microvessels in vivo. In vitro, EPO increased the proliferation, migration and clone formation of Lin- Sca-1+ SCs likely via the EPO receptor and downstream STAT-5/p38 MAPK signaling pathways. These results suggest that EPO participates in the repair process of MI by activating Sca-1+ SCs.

Role of autophagy in TXNIP overexpression-induced apoptosis of INS-1 islet cells / 生理学报

Thioredoxin (Trx) interacting protein (TXNIP) is a Trx-binding protein that inhibits the antioxidative function of Trx and is highly expressed in the serum and tissue samples from diabetes patients. This study was to explore whether TXNIP overexpression could cause INS-1 cell autophagy under normal glucose and lipid concentrations, and to analyze the role of autophagy in the apoptosis of INS-1 cells. The INS-1 cells cultured under normal conditions were divided into three groups: normal control, empty adenovirus vector (Ad-eGFP) and TXNIP overexpression (Ad-TXNIP-eGFP) groups. Forty-eight hours after transfection, the expression levels of TXNIP mRNA and protein were measured. Western blot was used to examine the protein expression levels of Beclin-1 and P62, as well as LC3-II/LC3-I ratio, which are associated with autophagy. IF/ICC was used to measure the autophagosome. In addition, the cleaved caspase-3/caspase-3 ratio, the apoptosis marker, was also measured, and the apoptotic rates were detected by flow cytometry (FCM). The results showed that the TXNIP mRNA and protein levels were significantly up-regulated in Ad-TXNIP-eGFP group, suggesting that TXNIP overexpression model was successfully established. In Ad-TXNIP-eGFP group, the protein levels of Beclin-1 and LC3-II/LC3-I ratio were increased, while the protein expression of P62 was decreased, compared with those in Ad-eGFP group. Red fluorescent intensity, representing autophagy level, was higher in Ad-TXNIP-eGFP group than that in Ad-eGFP group. These results suggested that TXNIP overexpression can significantly promote INS-1 cell autophagy. Meanwhile, cleaved caspase 3/caspase 3 ratio and the number of apoptotic cells were significantly increased in Ad-TXNIP-eGFP group. The inhibitor of autophagy, 3-MA, reduced TXNIP overexpression-induced apoptosis in INS-1 cells. Taken together, our data demonstrate that autophagy appears to be an important pathway in TXNIP overexpression-induced apoptosis in INS-1 cells.

A time series analysis on under 5 mortality rate in Zhejiang Province / 预防医学

Objective To study the temporal distribution regular pattern of under 5 mortality rate(U5MR)from 1 998 to 201 4 in Zhejiang Province,and to predict the under 5 mortality rate in 201 5.Methods A time series ARIMA (p,d,q) forecasting model for U5MR was conducted using IBM SPSS Statistics 20.0 statistical analysis software.Results The UMAR showed downward trend.The ARIMA(2,1 ,2)model of U5MR from 1 998 to 201 4 in Zhejiang Province is yt =-0.696 +0.636yt -1 +0.024yt -2 +0.340yt -3 +αt -0.003αt -1 +0.997αt -2 ,and the model fitting was good.Each of the actual mortality was consistent with the trend of model prediction,and was within the 95% confidence interval.The predicted value of U5MR was 4.08‰ (95% CI:1 .52‰ -6.64‰)in 201 5.Conclusion Time series analysis is an effective way to analyze the temporal distribution regular pattern of U5MR,which could be used for short -term prediction.

Cardiac ischemia in type 2 diabetes mellitus rats induced by high sucrose and high fat diet and STZ treated / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To build a type 2 diabetes mellitus rat model with cardiac ischemia.</p><p><b>METHODS</b>Male Wistar rats were fed high sucrose and high fat diet for four weeks and then injected with streptozoticin (STZ) (40 mg/kg .i.p.). The levels of fasting blood glucose and serum insulin were monitored every week. The body weights of rats were also measured every week. The blood levels of creatine kinase and lactate dehydrogenase (LDH) were measured following the electrocardiograph used BL-410 biological experiment system.</p><p><b>RESULTS</b>The serum insulin levels of diabetic rats were 4.05 ng/ml after four weeks high sucrose and high fat diet. The fasting blood glucose levels of diabetic rats were 17.9 mmol/L after injection. Compared with normal group, there was obvious change of S-T segment in the electrocardiograph of diabetic group at the fourteenth week. The levels of creatine kinase and lactate dehydrogenase in diabetic group significantly increased in comparison with those in normal group.</p><p><b>CONCLUSION</b>The cardiac ischemia of diabetic rats model is suitable for investigating cardiac disease of diabetes mellitus.</p>

Losartan reduced connexin43 expression in left ventricular myocardium of spontaneously hypertensive rats / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

<p><b>OBJECTIVE</b>To assess the effect of angiotensin II type 1 (AT(1)) receptor antagonist losartan on myocardium connexin43 (Cx43) gap junction (GJ) expression in spontaneously hypertensive rats (SHRs) and investigate possible mechanisms.</p><p><b>METHODS</b>Sixteen 9-week-old male SHRs and 8 age-matched male Wistar-Kyoto (WKY) rats were included in this study. SHRs were randomly divided into two groups to receive losartan at 30 mg/(kg x d) by oral gavage once daily for 8 weeks (SHR-L) or vehicle (0.9% saline) to act as controls (SHR-V); WKY rats receiving vehicle for 8 weeks served as normotensive controls. At the end of the experiment, rats were sacrificed and the hearts were removed. Expressions of Cx43 and nuclear factor-kappaB p65 (NF-kappaB p65) proteins in all three groups were observed and further investigations on the effect of angiotensin II type 1 receptor antagonist losartan (30 mg/(kg x d), 8 weeks) on Cx43 expression were conducted with Western blot and immunohistochemistry. NF-kappaB p65 protein in nuclear extracts was determined by Western blot.</p><p><b>RESULTS</b>Left ventricular (LV) hypertrophy was prominent in SHRs, Cx43 and NF-kappaB p65 protein expressions were obviously upregulated and Cx43 distribution was dispersed over the cell surface. Treatment with losarton reduced the over-expressions of Cx43 and NF-kappaB p65 in LV myocardium. The distribution of Cx43 gap junction also became much regular and confined to intercalated disk after losartan treatment.</p><p><b>CONCLUSION</b>Cx43 level was upregulated in LV myocardium of SHR during early stage of hypertrophy. Angiotensin II type 1 receptor antagonist losartan prevented Cx43 gap junction remodeling in hypertrophied left ventricles, possibly through the NF-kappaB pathway.</p>

Inhibition effect of topotecan on human myelodysplastic syndrome cells in vitro and in vivo / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effect of topotecan (TPT) on human myelodysplastic syndrome (MDS) cells in vitro and in vivo.</p><p><b>METHODS</b>Cell growth was measured by a MTT assay. The percentage of cells undergoing apoptosis was determined by flow cytometry after staining with annexin V-FITC and propidium iodide. The morphology of apoptotic cells was observed by transmission electron microscopy (TEM). Furthermore, the antitumor effect on MDS cells in xenotransplanted severe combined immunodeficiency (SCID) mice was evaluated by tumor volume and survival. Western blot was used for determining the expression of topoisomerase I (Top1) protein.</p><p><b>RESULT</b>The growth of Mutz-1 cells was suppressed by TPT treatment in a dose-dependent manner. The 50% inhibition in Mutz-1 cell growth (IC(50)) of TPT for 72 h was 272 ng/L. The percentage of apoptotic cells observed in the Mutz-1 cells after exposure to TPT (160 ng/L) in 48 h and 72 h was (54.16 +/-4.29)% and (72.97+/-6.12)%, respectively. TEM showed the characteristics of apoptosis in Mutz-1 cells treated with TPT. The xenotransplanted SCID mice treated with TPT showed inhibited tumor growth compared with control group. TPT treatment resulted in a longer survival as compared with the control group (P<0.001) and with the As2O3-treated group (P<0.001). The cells exposed to TPT exhibited a time-dependent decrease of Top1 protein expression.</p><p><b>CONCLUSION</b>TPT can inhibit Mutz-1 cell growth and induce apoptosis in vitro.The downregulation of Top1 may be involved in the apoptosis induced by TPT. TPT has a significant antitumor effect in vivo.</p>