Supraphysiologic Glucose Induces Expression Of Uncoupling Protein-2 On Rat Islets

ObjectiveTo investigate the effect of supraphysiologic glucose on uncoupling protein -2(UCP2) expression on isolated rat islets and its reversibility.MethodsRat islets were isolated and incubated for 3 days with glucose (5. 5,11 , 22mM). Some islet batches were incubated at high (11,22mM) , and subsequently lower(5. 5mM) glucose to assess reversibility of effects. The expression of UCP2 on islets was confirmed by RT - PCR.ResultsUCP2 expression in all islet batchs increased and then decreased along with increasing glucose concertration. UCP2 expression appeared to be higher on islets exposed to 11mM glucose than 5.5mM(p <0.05) ,but UCP2 expression on islets had no significant difference between 5. 5mM and 22mM( p >0. 05) . Islets incubated in 11mM glucose for 3 days and then for further 3 days in 5. 5mM glucose exhibit depressed levels of UCP2 mRNA when compared with those only incubated for 3 days in 11mM glucose (p <0.05). Islets incubated in 22mM glucose for 3 days and then for 3 days in 5. 5mM glucose didn't change significantly, when compared with those only incubated for 3 days in 22mM glucose( p >0. 05).ConclusionSupraphysiologic glucose exposure causes an increase in UCP2 expression in a certain extent and which can be a reversal subsequently with lower glucose. UCP2 could be an important mediator of hyperglycemia - induced (3 cell dysfunction.