Abstract
Interleukin (IL)-1β, the sole proinflammatory cytokine released from pancreas-infiltrating macrophages, inhibits glucose-stimulated insulin secretion (GSIS), causing hyperglycemia in Cohen diabetes-sensitive (CDs) rats fed a diabetogenic-diet (CDs-HSD). Because IL-1β blockade is a potential therapeutic target in diabetes, we examined whether treating CDs rats with IL-1β antibody (IL-1βAb; 0.5 mg/kg body weight) could counteract the inhibition of GSIS and hyperglycemia. We found that daily IL-1βAb injections had a beneficial effect on glucose tolerance and insulin secretion in CDs-HSD rats. In the oral glucose tolerance test, IL-1βAb-treated CDs-HSD rats showed lower blood glucose concentrations (P < 0.001) and higher GSIS (P < 0.05) compared with nontreated CDs-HSD rats. IL-1βAb treatment also protected the exocrine pancreas; the number of infiltrating macrophages decreased by 70% (P < 0.01) and IL-1β expression decreased by 85% (P < 0.01). In parallel, a 50% reduction (P < 0.01) in the rate of apoptosis and in fat infiltration (P < 0.05) was noted in the exocrine parenchyma of IL-1βAb-treated CDs-HSD rats compared with nontreated CDs-HSD rats. Altogether, these data demonstrate that blocking IL-1β action by IL-1βAb counteracted β-cell dysfunction and glucose intolerance, supporting the notion that prevention of pancreas infiltration by macrophages producing IL-1β is of crucial importance for the preservation of β-cell function and prevention of diabetes.