Abstract:

BACKGROUND: Hyperproliferation of vascular smooth muscle cells (VSMCs) is one of the most important mechanisms of atherosclerosis and restenosis. Receptor activity modifying protein-1 (RAMP1) is receptor subunit of calcitonin gene related peptide (CGRP) and decides the activity of receptor. Exogenous RAMP1 could play an important role in the regulation of VSMCs proliferation. 
OBJECTIVE: To investigate the effects of adenovirus mediated human RAMP1 (hRAMP1) gene on proliferation and apoptosis of VSMCs derived from rabbit thoracic aorta.
METHODS: VSMCs, isolated from rabbit thoracic aorta, were divided into three groups: hRAMP1 group, empty-adenovirus vector group and control group according to whether transferring Ad-EGFP-hRAMP1 or Ad-EGFP, and each group included four subgroups of 24 hours, 48 hours, 72 hours and 96 hours. RAMP1 protein was detected by immunocytochemistry, and the proliferation of VSMCs was determined by cell counting and MTT assay, and the apoptosis of VSMCs was determined by flow cytometry and TUNEL assay.
RESULTS AND CONCLUSION: VSMCs were successfully infected by Ad-EGFP-hRAMP1 or Ad-EGFP, and EGFP expression was increased, peaked at 72 hours and lasted for 96 hours. In the hRAMP1 group, the VSMCs showed hRAMP1 protein expression, and the activity of cell proliferation was significantly inhibited in the hRAMP1 group compared with empty adenovirus vector group and control group (P < 0.05). Also, the level of VSMCs apoptosis was significantly higher in the hRAMP1 group compared with other groups (P < 0.05). These results showed that the over-expression of hRAMP1 mediated by adenovirus vector plays an important role in inhibition of VSMCs proliferation and promotion of VSMCs apoptosis, which may be the therapeutic target of atherosclerosis and restenosis.