Insulin treatment of diabetic rats reduces cardiac function in a lipopolysaccharide-induced systemic inflammation model.

Abstract

BACKGROUND: Diabetes is a common comorbidity in patients with various medical conditions. Tight glucose control is known to improve systemic inflammation; however, whether it is effective in diabetic patients is unknown. The purpose of this study was to examine how strict glucose control affects systemic inflammation in diabetic patients. MATERIALS AND METHODS: Male Wistar rats. We determined the effect of insulin therapy on cardiac function in a rat model of systemic inflammation. We administered lipopolysaccharide intravenously, with or without insulin, to streptozotocin-induced diabetic rats. After induction of systemic inflammation, we determined serum cytokine (IL-6 and TNFα) and nitrate/nitrite levels and measured cardiac function. RESULTS: Cytokine levels and cardiac function were significantly reduced in diabetic rats compared to non-diabetic rats. Moreover, insulin treatment was associated with higher cytokine levels and decreased cardiac function. CONCLUSION: In systemic inflammatory conditions, diabetes increases various proinflammatory mediators and inhibits cardiac function; insulin treatment exacerbates these effects. Thus, strict glucose control may not be desirable in diabetic patients with systemic inflammatory conditions.