Effect and significance of losartan on the angiotensin converting enzyme 2 in therosclerotic plaques

Objective To investigate the effect of losartan on angiotensin converting enzyme 2 (ACE2)activity and ACE2、Ang-(1-7) protein level in rabbit atherosclerotic plaques and analyse its meaning. Methods Male New Zealand White rabbits were constructed atherosclerosis models.The rabbits were randomly 3 groups: high cholesterol group, losartan group and losartan+ A779 group.ACE2 activities were measured by enzymatic assay.The lipid content was evaluated by Oil red O stain, the proteins expression of ACE2、Ang-(1-7) and macrophage infiltration were also detected by immunohistochemistry.The differences of the protein expression of ACE2 were compared with chi-square test and t-test. Results The ACE2 activity higher in losartan group [(2.66±0.19)U/(μg protein·h)] and Losartan+ A779 group [(2.57±0.17)U/(μg protein·h)] than those in high-cholesterol group [(1.30±0.18)U/(μg protein·h)], and there was significant difference(t=15.87, 15.45; P 0.05). Conclusion The results show that ACE2 activity and ACE2、Ang-(1-7) protein are regulated in atherosclerotic plaque by losartan, which may play an important role in the treatment of AS, proterin and ACE2, Ang-(1-7) protein. Key words: Losartan; Angiotensins; Peptidyl-dipeptidase A; Atherosclerosis