Interfering RNA (iRNA) represents a recent breakthrough in effective blocking of the target genes in mammalian cells. Angiotensin-converting enzyme (ACE) has been shown to play an important role in the pathogenesis of hypertension. The purposes of this study were to investigate the effects on blood pressure, myocardial hypertrophy and gene expressions of iRNA targeting ACE.

Twelve week old male Wistar-Kyoto rats were grouped as follows: control group (C group), spontaneously hypertensive rat (SHR) group (H group), and ACE-iRNA group (A group) in which SHR was treated with recombinant lentiviral vectors carrying small hairpin RNA targeting ACE. Reverse transcription-polymerase chain reaction and western blot analysis of ACE, endothelin (ET)-1, angiotensin (AT) II receptor type 1A, neutrophil cytosolic factor, caspase 3, Bax, and Bcl-2 were performed in the heart tissues. Serum AT, ACE, and high sensitive-C reactive protein were estimated.

Systolic blood pressure was significantly decreased in the A group compared with the H group in weeks 3 and 5. Serum AT level was significantly lower on day 1, weeks 3 and 5 after ACE-iRNA treatment. ACE protein contents were significantly lower after ACE-iRNA treatment in week 5. ET-1 and Bcl-2 protein contents were significantly lower after ACE-iRNA treatment in weeks 3 and 5. Bax protein contents were significantly lower after ACE-iRNA treatment in week 3.

Recombinant lentiviral vectors carrying shRNA targeting ACE prevented hypertension. Serum AT and gene expressions such as ACE, ET-1, Bax, and Bcl-2 were significantly decreased after ACE-iRNA treatment.