Deficiency of Calpain-1 attenuates atherosclerotic plaque and calcification and improves vasomotor dysfunction in Apolipoprotein E knockout mice through inhibiting inflammation

Purpose Atherosclerosis (AS) and atherosclerotic calcification (AC) are closely related to the cardiovascular diseases, largely due to its induction of vasomotor dysfunction. We previously reported that Calpain-1 inhibitor attenuated AS and AC. The present study was designed to investigate the effects and potential mechanisms of Calpain-1 knockout (Calpain-1 KO) in Apolipoprotein E KO (ApoE KO) mice on AS, AC, aortic vasomotor function as well as the liver dysfunction. Methods We hybridized ApoE KO mice with Calpain-1 KO mice to obtain ApoE /Calpain-1 double KO (A×C DKO) mice. The formation of AS and AC was evaluated and liver function was determined. Aortic vasomotor function was assessed. Contents of TNF-α, IL-6, IL-18, IL-1β and NO and the activity of AST, ALT, ALP and eNOS in serum were quantified. The mRNA expression of CD68, SR-A, CD36, PPAR-γ, LXR-α, ABCA1, BMP-2, OPN, ALP and Runx2 in aorta and/or liver were measured. Results The results showed that in comparison to C57 mice, ApoE KO mice demonstrated the significant increases in the areas of AS and AC, the increases in the mRNA expression of CD68 in the aorta, the increases in the AST, ALT and ALP activity in serum. ApoE KO mice also showed the dysfunction of the aortic contraction induced by phenylephrine and of the relaxation induced by acetylcholine. However, compared with ApoE KO mice, A×C DKO mice exhibited the significant attenuation of AS and AC and the downregulation of mRNA expression of CD68 in aorta. A×C DKO mice revealed the reduction of AST, ALT and ALP activity in serum, the improvements in aortic contraction and relaxation as well as the increases in eNOS activity and NO content in serum. A×C DKO mice also showed the decreases in the contents of TNF-α, IL-6, IL-18 and IL-1β in serum. The mRNA expression of CD68 in aorta, SR-A and CD36 in both aorta and liver of A×C DKO mice was downregulated, while that of PPAR-γ, LXR-α, and ABCA1 was upregulated in comparison of ApoE KO mice. In addition, the mRNA expression of BMP-2, OPN, ALP and Runx2 in aorta of A×C DKO mice was downregulated in comparison of ApoE KO mice. Conclusion The results suggested that deficiency of Calpain-1 attenuated the formation of AS and AC and improved vasomotor and liver dysfunction in ApoE KO mice through anti-inflammation, and modulation of the mRNA expression of genes related to AS and AC.