动物造模 z-bio 2022-03-01 195

　　OBJECTIVE: To observe the changes of insulin secretion in the first phase of pancreatic islets in db/db mice after blocking the expression of local angiotensin II type 1 receptor (AT1R) by RNA interference technology, and to explore its potential mechanism.

　　METHODS: Pancreatic islets of db/db and db/m mice were isolated and the expression of AT1R mRNA and protein was detected. The RNA interference recombinant adenovirus (Ad-siAT1R) targeting mouse AT1R gene and the recombinant adenovirus containing the control sequence (Ad-siControl) were constructed. The isolated and cultured islet cells of db/db mice were divided into three groups: Ad-siAT1R infection group, Ad-siControl infection group and blank control group. Islet cells were cultured for 72 h after adenovirus infection. The expressions of AT1R, GLUT-2 and glucokinase (GCK) in each group were detected, and the dynamic secretion of insulin was detected by islet perfusion system.

　　RESULTS: The expression levels of AT1R mRNA and protein in the pancreatic islets of db/db mice were about 2 times higher than those of pancreatic islets of db/m mice (P<0.05). After adenovirus infection, compared with the Ad-siControl group, the expression level of AT1R mRNA in the Ad-siAT1R group decreased by 75%, and the protein expression level decreased by 65%, while the expression levels of GLUT-2 and GCK increased by 190% and 121%, respectively (both P<0.05). 0.05). Islet perfusion showed that the first phase of insulin secretion in the blank control group and Ad-siControl group decreased significantly, which was only 1.8 times the basal level; while the Ad-siAT1R group reached the highest peak 140 140 min after high glucose load. mU/L, 2.8 times the basal level, indicating a marked improvement in first-phase insulin secretion.

　　Conclusion: RNA interference-specific blocking of local AT1R expression in islets can up-regulate the expression of GLUT-2 and GCK, and restore the first-phase insulin secretion, which may be one of the mechanisms by which AT1R blockers improve islet secretion.