UCP-2 is involved in angiotensin-II-induced abdominal aortic aneurysm in apolipoprotein E-knockout mice

UCP-2 shows an important role in modulating of mitochondrial membrane potential and cell apoptosis. Whether or not UCP-2 could been a critical factor in preventing AAA formation is not known. We report that UCP-2 protein and mRNA expression were significantly higher in Ang-Ⅱ-induced AAA of mice. The incident rate of AAA in UCP-2-/-ApoE-/- mice after Ang-Ⅱtreatment was higher than the rate in the UCP-2+/+ApoE-/- mice. The abdominal aorta from UCP-2-/-ApoE-/- mice showed the medial hypertrophy, fragmentation of elastic lamellas and depletion of α-SMA. The NADPH oxidase activity and level of MDA was significantly higher in UCP-2-/-ApoE-/- mice than UCP-2+/+ApoE-/- or WT mice. Besides, the SOD activity is increased in UCP-2+/+ApoE-/- mice as compared with WT mice, whereas deficiency of UCP-2 decreased the increasing SOD activity in Ang-Ⅱ treated ApoE-/- mice. UCP-2 knockout up-regulated the MMP2 and MMP9 expression in aortic aneurysm. Ang-Ⅱ induced apoptosis of VSMCs was increased in UCP-2-/-ApoE-/- mice. And the expression of eNOS in vascular tissue from UCP-2-/-ApoE-/- mice is lower than WT and UCP-2+/+ApoE-/- mice. This study provides a mechanism by which UCP-2, via anti-oxidants and anti-apoptosis, participates in the preventing of AAA formation.