Fig. 1.

Expression of p16^Ink4a and p21^Cip1 in various tissues of parabiotic mice. A Schematic of isochronic and heterochronic parabiotic pairings of 4- and 18-month-old mice. B Total RNA was isolated from snap-frozen tissues collected from parabiotic mice (n = 5–8 mice per group). Expression of senescence markers Bp16^Ink4a and Cp21^Cip1 was measured by qPCR using the ∆∆Ct method and normalized to Gapdh expression. Values represent the mean ± SD and one-way ANOVA with Tukey’s test. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001