Markers to assess proliferation and apoptosis.

<p>Identification of proliferative cells in different stages of the cell cycle and those undergoing apoptosis in porcine small intestine and colon are shown. All proliferative markers localized to the nuclei of positive epithelial cells. Immunostaining for PCNA, a general marker for cellular proliferation, demonstrated the greatest number of positive cells compared to the other markers of proliferation. Immunostaining for MCM2, a marker of cells at the G1 stage of the cell cycle, was localized to a subpopulation of cells within the crypt base. Immunostaining for BrdU, a marker of cells within the S stage of the cell cycle, was also localized to a subpopulation of cells within the crypt base. Immunostaining for pH3, a marker for cells between the G2 – M stage of the cell cycle was similarly localized but to fewer cells. Immunostaining for cleaved caspase 3, an indicator of apoptosis, marked a few expressing cells near the villus tip within small intestine and the luminal surface of colon. All specific markers (red). Nuclei (blue) Scale bar 200 µm, inset scale bar 50 µm.