Fig. 4. Deletion of Bax and Bak reduces the SASP in vivo.
a, Schematic of the experimental procedure (top). Bottom, representative immunohistochemical image showing successful deletion of Bax in the liver after AAV injection. Scale bar, 100 µm. b, Quantification of mRNA levels of the indicated SASP genes in the livers of Sham- and 4-Gy-irradiated Baxfl/flBak−/− and Bak−/−Bax−/− mice. n = 5 (sham-IR Baxfl/flBak−/− and 4Gy-IR Bak−/−Bax−/−) and n = 4 (sham-IR Bak−/−Bax−/− and 4-Gy-IR Baxfl/flBak−/−) mice. Values are expressed as the fold change compared with sham-irradiated Baxfl/flBak−/− mice. c, Schematic of the experimental procedure. d, Quantification of mRNA levels of Bax in the livers of aged Baxfl/flBak−/− mice after tail-vein injection of AAV-Cre virus. n = 5 (Baxfl/flBak−/−) and n = 4 (Bak−/−Bax−/−) mice. e,f, Quantification of mRNA expression of the indicated SASP genes (e) and of Cdkn2a and Cdkn1a (f) in young (y; n = 5) and old (n = 5) wild-type mice and aged Baxfl/flBak−/− mice (n = 5) after AAV-Cre virus injection (n = 4). g, Representative immunofluorescence image of CD45 (red) and CD68 (green) in the livers of aged Baxfl/flBak−/− (n = 5) and Bax−/−Bak−/− mice (n = 4). Scale bar, 30 µm. h, Quantification of g. i, The correlation coefficient between expression levels of Bax and different SASP factors in the livers of aged Baxfl/flBak−/− and Bax−/−Bak−/− mice. Data are mean ± s.e.m. Statistical significance was assessed using two-way ANOVA followed by Tukey’s multiple-comparison test (b, e and f), two-sided Student’s unpaired t-tests (d and h) and Pearson’s correlation coefficient (i); *P < 0.05, **P < 0.01, ***P < 0.001.