Molecular Mechanisms of Angiotensin-converting Enzyme Inhibitory Peptide LAP Activity on Apoptosis of Vascular Smooth Muscle

We observe the expression levels of apoptotic cells, Bcl-2/Bax and caspase-9 on abdominal aorta of spontaneously hypertensive rats (SHRs) to investigate impact and mechanisms of angiotensin converting enzyme inhibitory peptide LAP in apoptosis of vascular smooth muscle cell. A total of 20 male SHRs were studied to detect apoptotic cells and the expression of apoptosis-related proteins (Bcl-2, Bax, caspase-9). The index of apoptotic cells in LAP group was significantly lower compared to the control group. The expression of Bcl-2 in the LAP group was significantly higher than the control group. However, the levels of Bax and caspase-9 expression in the LAP group were significantly lower compared to the control group. The apoptosis index was negatively correlated with Bcl-2 and positively correlated with Bax/caspase-9. Similarly, the inflammation markers in LAP group were significantly lower than those in the control group. The expression of Ang II was significantly decreased after treating with LAP in the abdominal arteries. Angiotensin- converting- enzyme inhibition peptide LAP inhibited apoptosis of vascular smooth muscle cells through up-regulation of Bcl-2 and down-regulation of Bax and caspase-9 in SHRs.