Redox Modulating Factors Affect Longevity Regulation in Rotifers.

Rotifers are microinvertebrate models to study the phylogenetically based mechanisms of aging. Our study aimed to develop a physiological system with electron deprivation via a chemical electron carrier/acceptor pair together with extreme caloric restriction (ECR). Middle-aged Philodina acuticornis rotifers were treated with combinations of phenazine methosulfate (PMS, electron carrier) and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide inner salt (XTT, electron acceptor) for a period of 72 hours under total food deprivation (preselection). The ability of XTT to be reduced was confirmed both in vitro (with NADH) and in vivo (with live rotifers). Subsequently, the respective electron acceptor alone at a lower dose was administered in combination with ECR for several months on preselected survivors. We found that the longevity of rotifers markedly increased (4×) after PMS/XTT/total food deprivation preselection followed by XTT/ECR treatment. Ascorbic acid in equivalent concentrations caused similar but less pronounced tendencies. The synergistic effect of chemical electron deprivation and ECR caused delayed aging and the development of an outstanding phenotype that we refer to as "super rotifers," characterized by increased longevity and retained reproductive ability compared with normal middle-aged individuals. The presented model provides new insights into the connection between redox modulation and age-related features in vivo.