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BACKGROUND@#Islet transplantation is currently considered the most promising method for treating insulin-dependent diabetes. The two most-studied artificial islets are alginate-encapsulated b cells or b cell spheroids. As three-dimensional (3D) models, both artificial islets have better insulin secretory functions and transplantation efficiencies than cells in twodimensional (2D) monolayer culture. However, the effects of these two methods have not been compared yet. Therefore, in this study, cells from the mouse islet b cell line Min6 were constructed as scaffold-free spheroids or alginate-encapsulated dispersed cells. @*METHODS@#MIN6 cell spheroids were prepared by using Agarose-base microwell arrays. The insulin secretion level was determined by mouse insulin ELISA kit, and the gene and protein expression status of the MIN6 were performed by Quantitative polymerase chain reaction and immunoblot, respectively. @*RESULTS@#Both 3D cultures effectively promoted the proliferation and glucose-stimulated insulin release (GSIS) of MIN6 cells compared to 2D adherent cells. Furthermore, 1% alginate-encapsulated MIN6 cells demonstrated more significant effects than the spheroids. In general, three pancreatic genes were expressed at higher levels in response to the 3D culture than to the 2D culture, and pancreatic/duodenal homeobox-1 (PDX1) expression was higher in the cells encapsulated in 1% alginate than that in the spheroids. A western blot analysis showed that 1% alginate-encapsulated MIN6 cells activated the phosphoinositide 3-kinase (PI3K)/serine/threonine protein kinase (AKT)/forkhead transcription factor FKHR (FoxO1) pathway more than the spheroids, 0.5% alginate-, or 2% alginate-encapsulated cells did. The 3D MIN6 culture, therefore, showed improved effects compared to the 2D culture, and the 1% alginate-encapsulated MIN6 cells exhibited better effects than the spheroids. The upregulation of PDX1 expression through the activation of the PI3K/AKT/FoxO1 pathway may mediate the improved cell proliferation and GSIS in 1% alginate-encapsulated MIN6 cells. @*CONCLUSION@#This study may contribute to the construction of in vitro culture systems for pancreatic islets to meet clinical requirements.
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AIM In this study, we observe the effects of SQS on contents of myocardial malondialdehyde(MDA)and activities of superoxide dismutase(SOD) and glutathione peroxidase(GSH Px) through adopting the model of myocardial ischemic injury induced by subcutaneous injection of isoprenaline(ISO 4 mg?kg -1 ?d -1 ?2 d) into rats. METHODS Four groups were divided, namely NS, I/R, SQS1 and SQS2 group. The contents of MDA and activities of SOD and GSH Px were examined after administering SQS for 3 days(1 time per day). RESULTS The results show the elevation of S T in ECG, increase of MDA contents and decrease of SOD and GSH Px activities in I/R group. SQS may antagonize the changes of MDA, SOD and GSH Px induced by ISO, revealing the relationship to dose dependence. CONCLUSION SQS is most likely to possess the capabilities of anti oxygen free radicals and anti lipoperoxidation to myocardial ischemic injury induced by ISO.
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AIM: To study protective effects as myocardial ischemic preconditioning of sasanquasaponin (SQS) and its relationship with K ATP channel. METHODS: The study adopted the model of myocardial ischemic injury induced by subcutaneous injection of isoproterenol (ISO) in rats, administering specific K ATP channel blocker gliberclamide (GLI 5 mg?kg -1 ). Four groups were set as NS group, I/R group, SQS group ( 0.2 mg?kg -1 ), and GLI group (5 mg?kg -1 ). Prior to injection of ISO, all agents were intraveneously injected into rats for 3 days, one time per day. Subsequently, ISO was subcutaneuously injected into rats by the ways of many different sites, and some indices were measured including ECG, serum creatine kinase (CK) activity, free fatty acid (FFA), and adenosine contents in rats. RESULTS: Preconditioningly intravenous injection of SQS could effectively protect myocardium from ischemic injury induced by ISO. With GLI injected prior to SQS, the cardioprotective effects of SQS were significantly attenuated. CONCLUSION: SQS can protect myocardium from ischemic injury induced by ISO, and the protection may be mediated by K ATP channel.
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Object To study the protective effect and pharmacological ischemic preconditioning of sasanquasaponin (SQS) on intact rat heart and its relationship with NO Methods A model of rat myocardial ischemia induced by sc injection of isoproterenol (ISO) was prepared, and after the administration of selective NO synthesis inhibitor methylene blue (MET), the ECG, serum creatine kinase (CK) activity, free fatty acid (FFA) and adenosine contents were determined Results Preconditioning iv injection of SQS can effectively protect the myocardium from ischemia induced by ISO The cardio protective effect was significantly attenuated when the NO synthesis inhibitor MET were injected prior to SQS Conclusion SQS can effectively protect myocardium ischemia induced by ISO and the protection is most likely to be mediated by NO