52 EFFECTS ON CARDIAC STRUCTURE IN ADULT RATS WHEN INTRAUTERINE GROWTH RESTRICTION IS COUPLED WITH HYPERGLYCEMIA

Abstract

Objective: Aim of this study was to examine the effect of type 1 diabetes on myocardial collagen deposition and cardiac function in IUGR rat offspring when blood glucose levels were maintained at either mild or moderate levels. Methods: IUGR was induced in Wistar-Kyoto rats by maternal protein restriction. At 24 weeks of age, diabetes was induced in male IUGR and non-IUGR offspring by streptozotocin injection; insulin was injected daily to maintain blood glucose levels at either a mild level (7-10mmol/L; n = 8 per group) or a moderate level (10-15mmol/L; n = 8 per group). Results: Morphological and echocardiographical analyses of the heart were performed at 32 weeks of age. There was induction of left ventricular hypertrophy in IUGR offspring of 32 weeks of age; this was accompanied by a thicker posterior wall and increased interstitial fibrosis. Induction of hyperglycemia also led to an increase in heart size and myocardial fibrosis. The response to hyperglycemia was not different between IUGR and non-IUGR adult rats however, cardiac fibrosis was greatest when diabetes was combined with IUGR. Conclusion: Tight glycemic control attenuated the adverse effects of hyperglycemia but did not reverse the increased collagen deposition. Exacerbated fibrosis in diabetic IUGR hearts even when glycemia is tightly controlled may lead to long-term cardiac dysfunction.