Platelet protects angiotensin II-driven abdominal aortic aneurysm formation through inhibition of inflammation

Background: Inflammation is the primary cause of abdominal aortic aneurysm (AAA) formation and development. It has been reported that platelets protect against septic shock by inhibiting inflammation. However, it is unclear whether platelets protect AAA progress via suppressing inflammation. Methods: A mouse model of AAA was established by a daily administration of angiotensin II (Ang II, 1000 ng/kg/min) for 28-day. The AAA mice received 1 × 109 platelets transfusion in normal saline every 3rd day for 1 month. Hematoxylin and eosin, Masson's trichrome, and elastic van Gieson staining techniques were used to analyze the morphology of the abdominal aorta. Immunohistochemistry was used to detect any infiltration of inflammatory cells, inflammatory factors, and matrix metalloproteins (MMPs) in the aortic tissue. Western blot and enzyme-linked immunosorbent assay (ELISA) were used to examine the inflammatory factor proteins levels in the aortic wall and peripheral blood, respectively. Results: Platelets infusion significantly suppressed the Ang II-driven elevation of aortic diameter, AAA formation (52.38% decrease, P < 0.05), aortic expansion, elastic lamina destruction, and inflammatory response. In addition, MMP-2 and MMP-9 production were also reduced by platelets transfusion. Conclusions: For the first time, our study reported the beneficial effect of platelet transfusion in suppressing the Ang II-driven AAA progress in mice through the inhibition of inflammation.