Effect of a calorically restricted dietary regime on oxidative post-translational modifications of plasma proteins in mice and rats

Department of Chemistry, Panchmura Mahavidyalaya, Panchmura, Bankura-722 156, West Bengal, India

E-mail : chandanjana@yahoo.com

Department of Biotechnology, Visva-Bharati University, Santiniketan-731 235, West Bengal, India

E-mail : nilanjana.das@visva-bharati.ac.in Fax : 91-3463-261101

Manuscript received online 07 November 2014, revised 02 December 2014, accepted 03 December 2014

The present investigation studies the effect of a long-term caloric restriction (CR) diet regime on the oxidative post-translational modifications in mouse and rat strains that are reported to exhibit a CR-mediated increase in their lifespan. The level of protein carbonyl formation in the plasma proteins of mice (C57BL/6Nnia) and rats (Fisher 344) under a CR diet investigated with respect to their ad libitum (AL) control animals using spectrophotometric, Western blot and/or tritiated sodium borohydride radioactive assay methods demonstrated no association of a long-term CR regime with any retardation in the age-associated increase in carbonylation. The overall level of protein carbonylation was found to be higher in the plasma of CR mice as compared to the respective AL control animals, although this difference was not statistically significant. In the case of rats on a CR diet, the level of carbonylation of two plasma proteins known to be selectively susceptible to oxidative stress in this species, albumin and alpha 1-macroglobulin, was similarly higher than AL control controls but the difference was not statistically significant. Thus, it may be concluded that the increase in lifespan associated with CR in animals across diverse species may not be associated with a universal decrease in oxidative stress. This response may be tissue-specific or may act through modification of other pathways.