2.1 Animals and experimental protocols
Seven-week-old male spontaneously hypertensive rats (SHRs; 190±10 g) and Wistar Kyoto rats (WKYs; 200±10 g) were purchased from Beijing Wei Tong Lihua Experimental Animal Center. Ten-week-old male C57BL/6 mice (25±2 g) were purchased from the Laboratory Animal Center of Xi’an Jiaotong University. Animals were housed in a room with a controlled environment (12/12-h light/dark cycle, 22-25°C, 50-60% relative humidity) with free access to normal diet and water. After study, all animals were anesthetized by inhalation of 1-2.5% isoflurane, and then euthanized by cervical dislocation. All animal experimental protocols were approved by the local and national ethical committee and conformed to NIH guidelines and the recommendations made by the British Journal of Pharmacology.
After 1 week of adaptation, SHRs were randomly divided into 3 groups of 8 rats each: recombinant adeno-associated virus (rAAV)-miR-26a (150 μl, i.v.); rAAV-GFP (150 μl, i.v.) (a total dose of viral particles was 2 × 1011 v.g.; the rAAV vectors we used were rAAV of type-9; rAAV of miR-26a and vector controls was synthesized by Han Heng Biotechnology, China); and SHR-Ctrl (normal saline 150 μl, i.v.). Six WKY rats were normal controls (normal saline 150 μl, i.v.). Systolic blood pressure (SBP) of the caudal artery of rats was measured every 3 to 5 days by using a non-invasive BP analysis system (BP-2000 SERIESII, Visitech, USA). After 3 weeks, plasma and thoracic aortas of rats were collected.
For mice experiments, C57BL/6 mice (n = 6 per group) received AngII (Merck, USA, 2.0 mg/kg/d) or normal saline subcutaneously by implanted ALZET® 2002 minipumps under isoflurane anesthesia. Two weeks later, plasma and thoracic aortas of mice were collected.