Objective: To investigate the effects of retroviral vector containing shRNA targeting rat angiotensin II type 1 receptor (AT1R) gene (Ad5-AT1R-shRNA) on blood pressure and AT1R mRNA expression in spontaneously hypertensive rats (SHR).
Methods: Retroviral vector containing shRNA targeting rat AT1R gene was constructed and propagated further in 293 cells. SHR rats were randomly divided into SHR + Ad5-AT1R-shRNA (1.7 x 10(9) TCID(50)/ml) group and SHR (Ad5-EGFP, 7.9 x 10(9) TCID(50)/ml, n = 11 each) and 11 male Wistar-Kyoto rats (WKY) serve as normal controls (Ad5-EGFP, 7.9 x 10(9) TCID(50)/ml). Systolic blood pressure was measured before and after single intravenous injection of Ad5-AT1R-shRNA or Ad5-EGFP. Heart, liver, kidney, aorta and adrenal gland were removed after blood pressure measurement. Tissue Ad5-AT1R-shRNA expression was detected with fluorescence microscope and AT1R mRNA in liver, kidney and aorta was measured by fluorescence quantitative PCR.
Results: Ad5-AT1R-shRNA significantly reduced blood pressure compared with controls (-29 mm Hg, 1 mm Hg = 0.133 kPa, P < 0.05) 24 hours after single injection and this antihypertensive effect could last for 5 to 7 days. Ad5-AT1R-shRNA expression detected with fluorescence microscope was significantly increased in heart, liver, kidney, aorta and adrenal gland post Ad5-AT1R-shRNA injection. AT1R mRNA in kidney and aorta (0.086 +/- 0.014, 0.051 +/- 0.023) were significantly decreased in Ad5-AT1R-shRNA treated rats compared with SHR control rats (0.362 +/- 0.042, 0.463 +/- 0.045, P < 0.01).
Conclusion: The results indicate that Ad5-AT1R-shRNA could inhibit the tissue AT1R mRNA expression and produce prolonged antihypertensive effects in SHR rats.