BAX and pulmonary emphysema: Interestingly, the size of the alveolar space in 3–4-month-old ku70−/−bax+/− and ku70−/−bax−/− mice were similar to that of wild type (Figure 4b), suggesting that the absence of Bax-mediated apoptosis can attenuate the development of emphysema in Ku70-null mice.