Apoptosis in aged but not young Bnip3-TG mice.

<p>TUNEL staining was implemented as described in Methods. (A) The sensitivity of the TUNEL assay was demonstrated by treating heart sections with DNAase I to induce TUNEL positive DNA strain breaks; top panel TUNEL, bottom panel DAPI; >80% of nuclei are TUNEL-positive (data not shown). (B) Apoptotic indices of wild type (WT) and Bnip3-TG mice were determined by TUNEL at the indicated times as described in Methods. Examples of TUNEL staining in heart sections from 5-week old wild type (C) and Bnip3-TG mice (D). Nuclei were co-stained with DAPI. Yellow arrows point to TUNEL positive nuclei and the corresponding DAPI stained nuclei. Results in (B) are mean ± S.E.M.; * p < 0.05, comparing apoptotic indices with 4–6 weeks (n = 5).