Figure 2. Irinotecan administration causes severe histological damage in the jejunum and colon of DA rats. Characteristic apoptotic bodies are visible at 6 and 96 h post-irinotecan. Gross architectural changes (villous blunting and crypt degeneration) are evident at 24 h, but are most severe at 48 and 72 h hours. Restoration of the epithelium is evident at 120 h, indicated by mitotically active cells. Original magnification 200× (villus) and 400× (crypt).