Developmental Time‐course of Vascular RNA Expression and Protein Levels for ACE, eNOS and iNOS in Young Syrian Cardiomyopathic Hamsters

Abstract

Endothelial dysfunction, increased oxidative stress, and alterations in the renin‐angiotensin system (RAS) are present in 2‐month‐old Syrian cardiomyopathic hamsters (SCH). To evaluate the developmental time‐course of these alterations, we assessed the protein levels and RNA expression of ACE, eNOS and iNOS in the vasculature of SCH from 1 to 4 months of age. Age‐matched golden hamsters were used as controls (CT). Total RNA and protein were extracted from aortic tissue. RNA expression was quantified with Real‐Time RT‐PCR, and protein levels were determined with Western blot. We found that ACE RNA was upregulated in 2‐month‐old SCH (from 38.85% to 141.18 %, P<0.05), when compared with 1‐month‐old SCH, and reached a plateau at 4 months. ACE protein levels were higher at 2‐months (1.54 arbritrary units; AU) than at 1 month (0.98 AU) and 4 months (.79 AU). In addition, eNOS RNA increased significantly in SCH from 1 to 4 months (from 49 % to 273%; P<0.05), but eNOS protein levels decreased after 1 month (1.06 AU), reaching its minimum at 2 months (0.34 AU, P<0.05). Vascular iNOS RNA and protein levels, by contrast, remained unchanged in SCH from 1 to 4 months. These results suggest that the increased ACE RNA and protein levels, together with the decreased eNOS protein content observed at 2 months, may be involved in the etiology of endothelial dysfunction that is present in 2‐month‐old SCH. Supported by MBRS‐RISE R25‐GM061838.