Total cellular protein (TP), cytosolic protein (CE), and nuclear protein (NE) extracts were respectively prepared from colonic mucosa using cold RIPA buffer and the NE-PER kit per the manufacturers' recommendations (Pierce, Rockford, IL). The nuclear abundance of p65 was detected in NE, SH-PTP1 was used as internal control for loading NE. IκBα, and β were determined in CE, β-tubulin was used as internal control for loading CE. Band intensities were quantified as mean area density using ImageQuant (Molecular Dynamics, Sunnyvale, CA). p65 (phosphoserine 276) was examined in paraffin-embedded intestinal sections using VECTASTAIN Elite ABC system (Vector lab, Burlingame, CA). BrdU staining followed manufacturer's instructions (BrdU In-Situ Detection Kit, BD Pharmingen, San Jose, CA) (Han et al. 2010 (link)). BrdU, Cleaved caspase-3, Ki67, and p65-positive cells were counted by a semiquantitative method and expressed as average positive cells per crypt. Images were captured using a Zeiss microscope and Axioviewer image analysis software (Carl Zeiss Corp, Germany) (Han et al. 2005 (link), 2009 (link)).