P53-Rb signaling pathway is involved in tubular cell senescence in renal ischemia/reperfusion injury.

Objective: To investigate the course of tubular cell senescence and expressions of p53, p21, and Rb during the late phase of ischemia/reperfusion (IRI) in the kidney, and assess the effects of the p53-Rb pathway on tubular cell senescence.

Methods: Experimental models of unilateral renal IRI were used in p53 (+/+) and p53 (-/-) mice. Histological changes at the tubular level, progress of cell senescence, and the expression of Rb, p21, and/or p53 proteins in tubular cells were studied at different moments in time after IRI.

Results: Chronic tubulointerstitial fibrosis was much more severe and widely distributed in IRI kidneys of p53 (+/+) mice in later stages than in earlier stages. Senescent tubular cells were significantly increased at 3 and 6 months after IRI. In contrast, in contralateral kidneys of p53 (+/+) mice and in both kidneys of p53 (-/-) mice, almost no senescent cells were observed at 1 and 3 months after IRI, and only a few senescent cells were detected in IRI kidneys of p53 (-/-) mice at 6 months. In mice of both genotypes, cell senescence was correlated with the expression levels of p53, p21, and Rb proteins.

Conclusion: The IRI accelerated tubular cell senescence is presumed to be one of the mechanisms of the "long-term effect" of IRI. Furthermore, the activation of p53-Rb signaling pathway may play a vital role in tubular cell senescence induced by IRI.