Protection And Mechanism Of Muscle-deirved Stem Cells Transplation In Pancreatic Islets Of Diabetic Mice

ObjectiveCultured SD rat muscle-derived stem cells in vitro, intravenous injectionof streptozotocin to diabetic rat model. Study protective effect of residual isletcells after MDSCs transplanted in diabetic rats, and to explore the possiblemechanisms of this protective effect.Methods1, Use the hybrid enzyme digestion method to extract the SD rat muscle-derived stem cells, differential adherence purified, observe cell morphology underan inverted microscope, and desmin immunocytochemistry Identification of muscle-derived stem cells.2, Make diabetic rat model with intravenous injection of streptozotocin. Themodel was established, were randomly divided into three groups, respectively,for the STZ group (pancreatic capsule injection of PBS); MDSCsa group (pancreatic capsule injection of muscle-derived stem cells); MDSCsb group(pancreatic capsule injection of muscle-derived stem cells+Ly294002).monitoring of blood glucose after transplantation weekly, immunohistochemistrywas observed in pancreatic tissue phosphorylation of Akt protein expression inislet,cell apoptosis by TUNEL staining, Western blot semi-quantitative detectionof pancreatic islet tissues of pAkt and Bcl-2/Bax the expression changes, IGF-1mRNA expression was detected by RT-PCR. Results1, After differential adhesion, successfully cultured muscle-derived stemcells of high purity, Desmin immunocytochemistry was positive.2, blood glucose change: STZ group blood glucose gradually showed anincreasing trend; MDSCsb group,1week after transplantation (23.0±2.4mmol/L) blood glucose decline is not significant to the first four weeks (22.5±3.5mmol/L) changes in blood sugar is not obvious, respectively, with the STZ grou p(25.3±3.2mmol/L,26.4±2.8mmol/L) have no significant difference; bloodglucose have a significant drop in the first week after transplantati in MDSCsagroup (18.5±3.4mmol/L),with STZ group and MDSCsb group was statistically significant (P <0.05, P <0.05), blood glucose continued to drop to transplantation after4weeks (13.5±1.3mmol/L), with STZ group and MDSCsb group was statistically significant(P <0.05, P <0.05).3, pAkt in pancreatic tissue was observed with immunohistochemistry,pAkt protein positive for yellow or brown particles, diffuse distribution, positioning in the nuclear membrane, cytoplasm. protein expression of STZ group wassmall, protein expression of MDSCsb group relative increase, MDSCsa histoneexpression was significantly increased. TUNEL staining: the detection of morepositive cells in the STZ group and MDSCsb group in the rat pancreas, isletapoptotic cells increases, fewer positive cells in the MDSCsa group of islets,that is, fewer apoptotic cells. Western blot analysis found that, compared withthe STZ group and MDSCsb group, Bcl-2and pAkt protein expression ofMDSCsa group corresponding enhanced, expression of Bax protein decreased.RT-PCR found that, compared with the STZ group and MDSCsb group, IGF-1electrophoretic bands of MDSCsa group deep, IGF-1mRNA expression issignificantly increased. Conclusions1, Get high purity, vitality rat MDSCs step by mixing enzyme digestionmethod, Desmin Immunohistochemistry of their early identification.2, IGF-1gene relative expression level significantly increased islet cellapoptosis was significantly reduced, indicating that the MDSCs the paracrineplays a protective role of MDSCs transplanted diabetic rat islets.3, pAkt expression was significantly enhanced, indicating that the PI3K/Aktsignaling pathway regulate this protective effect.