Figure 8.

Immunohistochemistry for proapoptotic active caspase-3 and TUNEL. (a–d) Pdx1^+/– islets showed modest activation of caspase-3 in vivo (red staining) compared with Pdx1^+/+ islets. The difference was most prominent in older animals and varied between islets from the same pancreas section. (e–h) TUNEL-positive cells (red) are seen in Pdx1^+/– islets at all ages studied but are extremely rare in Pdx1^+/+ islets. Note the loss of intact islet structure and the striking increase in vascularization in Pdx1^+/– islets (arrow in h points to one of many red blood cells within the islet). Islet structure and TUNEL staining was also different in Pdx1^+/– islets at 5 months of age (not shown).