Background: This study aims to develop a fetal rat model of ventricular noncompaction (NVM) using streptozotocin (STZ)-induced gestational hyperglycemia and compare it with a retinoic acid (RA) model.
Methods: Female SD rats were categorized into STZ, RA, and normal control (NC) groups. The STZ group was given a high-fat diet pre-pregnancy and 35 mg/kg of 2% STZ postpregnancy. The RA group received a 90 mg/kg dose of RA on day 13 postpregnancy. Embryonic myocardial morphology was analyzed through HE staining, and embryonic cardiomyocyte ultrastructures were studied using electron microscopy. Diagnoses of NVM were based on a ratio of noncompact myocardium (N) to compact myocardium (C) >1.4, accompanied by thick myocardial trabeculae and a thin myocardial compaction layer. Kruskal-Wallis test determined N/C ratio differences among groups.
Results: Both STZ and RA groups displayed significant NVM characteristics. The left ventricular (LV) N/C in the STZ, RA, and NC groups were 1.983 (1.423-3.527), 1.640 (1.197-2.895), and 0.927 (0.806-1.087), respectively, with a statistically significant difference (P<0.001). The right ventricular (RV) N/C in the STZ, RA, and NC groups were 2.097 (1.364-3.081), 1.897 (1.337-2.662), and 0.869 (0.732-1.022), respectively, with a significant difference (P<0.001). Electron microscopy highlighted marked endoplasmic reticulum swelling in embryonic cardiomyocytes from both STZ and RA groups.
Conclusion: Our model underscores the pivotal role of an adverse intrauterine developmental environment in the onset of NVM. This insight holds significant implications for future studies exploring the pathogenesis of NVM.
Keywords: Animal model; Heart development; Maternal hyperglycemia; Retinoic acid; Streptozotocin; noncompaction of ventricular myocardium.
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