Immunohistochemical detection of oxidative stress biomarkers, dityrosine and Nε-(hexanoyl)lysine, and C-reactive protein in rabbit atherosclerotic lesions

Abstract

Several lines of evidence have demonstrated that C-reactive protein (CRP) is associated with oxidative stress; however, the precise co-localization between CRP and oxidative stress markers in atherosclerotic lesions is not fully established. In this study, we focused on two oxidative stress markers, dityrosine (DY) and Nε-(hexanoyl)lysine (HEL), which had not previously been investigated in relation to CRP in atherosclerotic lesions. Aim: We investigated the production and localization of DY, HEL, and CRP in early-stage and moderately progressed fatty lesions of cholesterol-fed rabbits by immunohistochemistry using specific monoclonal antibodies to examine the co-localization between CRP and oxidative stress in atherosclerotic lesions. Methods: Rabbit atherosclerotic specimens were obtained from New Zealand White rabbits fed a diet containing 1.0% cholesterol for 12 weeks. All specimens were fixed in formalin for histological examinations. Results: CRP-positive cells in rabbit early-stage and moderately progressed fatty lesions were detected mostly in the macrophage-derived foam cell-rich areas. Both DY and HEL were also detected in foam cell-rich areas in both lesions, where they were primarily co-localized with CRP-positive cells. Conclusion: Our results suggest that the generation of oxidative stress markers, DY and HEL, may be mediated by CRP in atherosclerotic lesions, and that CRP may be associated with oxidative stress in rabbit atherosclerotic lesions.