[Tanshinone IIA attenuates the development of elastase-induced abdominal aortic aneurysm of rat]

To determine if tanshinone IIA (Tan IIA) can influence the development of elastase-induced experimental abdominal aortic aneurysms (AAAs).

Totally 36 male Sprague-Dawley rats were randomly distributed into three groups (12 in each group): Tan IIA group, control group, and sham group. Rats of Tan IIA and control groups underwent intra-aortic elastase perfusion to induce AAAs, while rats of sham-group were perfused with saline. Rats of Tan IIA-group received Tan IIA treatment (2 mg/d). The luminal diameter of the aneurysm at the segment with maximum diameter were measured pre-perfusion and on the 4 time point after perfusion. Systolic blood pressure was measured by tail-cuff technique. Aortic tissue samples were obtained on 24 days after perfusion and evaluated by RT-PCR, Western blot, immunohistochemistry and Miller's elastin-Van Gieson's (EVG) staining.

Twenty-four days after perfusion, Tan IIA significantly reduced increased aortic size compared to control group ((0.210 ± 0.002) cm vs. (0.304 ± 0.004) cm, t = 78.858, P = 0.000) without affecting blood pressure (t = -1.237 to -1.221, P > 0.05). The over-expression of matrix metalloproteinases (MMP)-2/9 (t = 25.943, P = 0.000; t = 42.815, P = 0.000), monocyte chemotactic protein-1 (MCP-1) (t = 4.518, P = 0.000), inducible nitric oxide synthase (iNOS) (t = 17.685, P = 0.000) and the destruction of elastic fibers in aortic tissue of control group were significantly less than Tan IIA group (0.469 ± 0.040 vs. 0.230 ± 0.024, t = 17.944, P = 0.000).

Tanshinone IIA attenuates the development of elastase-induced experimental AAAs possibly by down-regulating MMP-2/9, MCP-1 and iNOS expression.