Histopathology and immunohistochemistry

As previously described, tissues harvested from mice were fixed in 10% neutral buffered formalin saline and embedded in paraffin (15). Tissues were processed, embedded in paraffin, cut into 5-μm sections, and subjected to H&E staining in MD Anderson’s Department of Veterinary Medicine and Surgery’s histology laboratory. Immunohistochemistry was performed using standard methods with citrate buffer for 30 min of antigen retrieval. Slides were stained with antibodies against cleaved caspase-3 [Cell Signaling Technology, catalog no. 9664 (also 9664P), RRID:AB_2070042] and 4HNE (Abcam, catalog no. ab46545, RRID:AB_722490). Visualization was performed using biotinylated secondary antibody kits (VECTASTAIN ABC and DAB kits, Vector Laboratories), with hematoxylin as the counterstain.