Dietary restriction delays the secretion of senescence associated secretory phenotype by reducing DNA damage response in the process of renal aging

Dietary restriction (DR) has multiple and essential effects in protecting against DNA damage in model organisms. Persistent DNA damage plays a central role in the process of aging. Senescence-associated secretory phenotype (SASP), as a product of cellular aging, can accelerate the process of cellular senescence as a feedback. In this study, we directly observed whether a DR of 30% for 6 months in aged rats could retard SASP by delaying the progression of DNA damage and also found the specific mechanism. The results revealed that a 30% DR could significantly improve renal pathology and some metabolic characteristics. The biomarkers and products of DNA damage were decreased in the process of renal aging on a 30% DR. A series of SASP, notably cytokine, chemokine, and growth factor, were obviously reduced by DR during renal aging. The phosphorylation levels of NF-κB and IκBα in aged kidneys of DR group were markedly reduced. These findings suggest that a 30% DR for 6 months can delay renal aging and reduce the accumulation of SASP by retarding the progression of DNA damage and decreasing the transcription activity of NF-κB, thus providing a target to delay renal aging.