Levo-Tetrahydropalmatine Attenuates Progression of Abdominal Aortic Aneurysm in an Elastase Perfusion Rat Model via Suppression of Matrix Metalloproteinase and Monocyte Chemotactic Protein-1

Background: Levo-tetrahydropalmatine (L-THP) is a tetrahydro protoberberine isoquinoline alkaloid obtained from the genera Stephania and Corydalis. In the present research, we evaluated the effects of L-THP on the progression of aortic aneurysms (AAs) in experimental rats induced with perfusion of elastase. Material/Methods: Thirty-six Sprague-Dawley rats were divided into sham-operated, control, and L-THP treated groups (n=12 in each group). The rats in the control group and the L-THP group received intra-aortic perfusion of elastase to induce AAs; the sham-operated group received perfusion of saline. The rats in the L-THP group received a dose of 15 mg/kg/day, the control and the sham group received saline treatment. The animals were evaluated for aortic diameters (ADs) and systolic blood pressure (SBP) just before and after the elastase perfusion, and 24 days after perfusion. The extracts of the aortas were evaluated by western blotting and immunohistochemistry. Results: In the control group, a significant increase in aortic size was observed (p<0.05) compared to the sham group after 24 days post-perfusion, whereas the L-THP group showed a decrease in diameter compared to the control group (p<0.05). The SBP increased significantly in the control group compared to the sham group. The L-THP group showed reduction in SBP, exhibited decreased expression of metalloproteinase and monocyte chemotactic protein-1, and the tissue samples also exhibited significant decreased levels of iNOS compared to the control group. L-THP treatment prevented loss of vascular smooth muscle cells (VSMCs) of the aortic walls. Conclusions: L-THP inhibited progression of AAs in rats by curbing inflammation, oxidative stress, and conserving VSMCs, suggesting a new therapeutic approach for managing AAs.