Vascular Enos And Inos Expression Is Altered In Young Syrian Cardiomyopathic Hamsters

Protein and mRNA expression of eNOS and iNOS were evaluated in aortic tissue from 2-month-old Syrian cardiomyopathic hamsters (SCH) to correlate these variables with the endothelial dysfunction (ED) present in SCH at this stage. The effects of 4 weeks of treatment, beginning at one month, with the antioxidant N-acetylcysteine (NAC, 1g/kg/d) and the β-blocker-antioxidant carvedilol (1mg/kg/d) were also assessed. Age-matched golden hamsters were used as controls (CT). Total RNA and protein were extracted from aortic tissue. Expression of mRNA was quantified with Real-Time RT-PCR, and protein levels were determined with Western blot. Our results showed up-regulation of eNOS mRNA expression (4-fold) in 2-month-old SCH when compare to CT (P<0.05). In contrast, eNOS protein levels in SCH were reduced by 75% when compared to CT (P<0.05). Expression of iNOS mRNA was 60% lower in SCH than in CT, although iNOS protein levels increased by 44% (P<0.05). Treatment of SCH with carvedilol or NAC normalized eNOS mRNA expression when compared to untreated SCH, without modifying iNOS expression. These results suggest that alterations in eNOS and iNOS mRNA and protein expression contribute to the increased oxidative stress and ED observed in 2 month-old SCH. Supported by NIH-SCORE S06-RR 08224.