| Objective:With HE staining to oberseve the pathological changes of pancreanic islet,the concentration of serum NO,the levels of expression of Insulin,Bax,Bcl-2,Pdx-1 and Ngn-3 were detected by immunohistochemistry in different blood glucose levels in pancreatic tissue of tree shrews induced by STZ, to explore the relationship of Bax, Bcl-2 and Pdx-1,Ngn-3 in pancreatic tissue of tree shrews between different blood glucose. To confirm the presence of pancreatic regeneration and possible mechanisms.Method:32 tree shrews were divided into STZ and control groups,The STZ group was observed 10 days after intraperitoneal injection of STZ (120mg/kg) of three times in two weeks.The STZ group was divided into four sub-groups according to the blood glucose:group A (normal blood glucose), Group B (the blood glucose first increased and then decreased to normal),group C(blood glucose increased but did not meet diagnosticcriteria for diabetes: blood glucose <11.1mmol/l),group D(diabetic group: blood glucose≥11.1mmol/l). The normal control group were given intraperitoneal injection of acidified saline treatment 5ml/kg.With HE staining to oberseve the pathological changes of pancreanic islet,The concentration of serum NO were detected by nitrate reductase,the levels of expression of Insulin,Bax,Bcl-2,Pdx-1 and Ngn-3 were detected by immunohistochemistry.Results:1.The islets of control group have clearly border, forms complete and regular,in larger quantities,uniform distribution in pancreas acinar.Group A, Group B remained normal islet morphology,cell volume compared to normal,relatively full island-shaped,the islet morphology of group C was basically normal,Boundaries are clear,size smaller than usual, the isletβcells are reduce, the islet of group D appeared different degrees of atrophy,the isletβcells were significantly reduce. 2.the levels of serum NO content in tree shrew group: group D>group C >group B>group A>control group.Group B compared with group C, group D were significantly(P<0.05),but with the group A and control group differences between groups were not significant(P>0.05). 3.Insulin expression in STZ treatment group was loewr than in the control group(P <0.05),group B was significantly higher than group C and group D,the difference was statistically significant(P<0.05),but compared with the group A have no significant differe-nce(P>0.05). 4.the expression of Pdx-1 and Ngn-3 in STZ treatment group was lower than the control group(P<0.05),group B was significantly higher than group C,group D,the difference was statistically significant(P<0.05),compared with the group A difference was not significant(P>0.05). 5.Bax expression in pancreatic islets:group D>group C>group B>control group>group A.Group C,D compared with the control group significantly(P<0.05), group B compared with group C,group D were significantly(P<0.05),but with the group A and control group differences between groups was not significant (P>0.05);Bcl-2 expression in STZ treatment group was loewr than in the control group,group B, group C, group D compared with the control group were significantly(P<0.05),group B compared with group C,group D is significantly(P<0.05),but with the group A is not signifi- cant(P>0.05). 6.Pancreatic Pdx-1,Ngn3 expression was negatively correlated with Bax and Bcl-2 was positively correlated(P<0.05).Conclution:1.The small dose of intraperitoneal injection many times of STZ-induced tree shrews models are stability,low mortality,can form different blood glucose levels,and conducive to observation of isletβcell regeneration. 2. Through the trees hrew isle tpathology,insulin,Pdx-1 expression and Ngn-3 confirmed the presence of islet regeneration in the tree shrew of blood glucose after STZ treatment remission on their own. 3.STZ treated tree shrew was possibly through the expression of Pdx-1,Ngn-3,affecting the expression of Bcl-2/Bax in tree shrew,playing a role in promoting residualβcell proliferation and regeneration,to some extentto promote restoration of islet function,improve glucose metabolism and insulin sensitivity.
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