Intestinal permeability to iohexol as an in vivo marker of chemotherapy-induced gastrointestinal toxicity in Sprague-Dawley rats

Purpose Gastrointestinal toxicity is the most common adverse effect of chemotherapy. Chemotherapeutic drugs damage the intestinal mucosa and increase intestinal permeability. Intestinal permeability is one of the key markers of gastrointestinal function and measuring intestinal permeability could serve as a useful tool for assessing the severity of chemotherapy-induced gastrointestinal toxicity. Methods Male Sprague-Dawley rats were injected intraperitoneally either with 5-fluorouracil (150 mg/kg), oxaliplatin (15 mg/kg) or irinotecan (200 mg/kg). Clinical signs of gastrointestinal toxicity were assessed daily by weighing the animals and by checking for diarrhea. After 48 h, intestinal permeability to iohexol was measured in vivo by giving the animals 1 ml of 647 mg/ml iohexol solution by oral gavage and collecting all the excreted urine for 24 h. All of the animals were euthanized 72 h after drug administration and tissue samples were harvested from the jejunum and colon. Results All chemotherapeutics caused significant body weight loss and diarrhea. Intestinal permeability to iohexol was also increased in all treatment groups and histological analysis revealed significant intestinal damage in both jejunum and colon. Iohexol permeability correlated with the severity of clinical signs of gastrointestinal toxicity and with acute colonic injury. Conclusions Chemotherapeutic drugs, such as 5-fluorouracil, oxaliplatin, and irinotecan, increase intestinal permeability to iohexol. Measuring intestinal permeability to iohexol could provide a simple marker for assessing chemotherapy-induced gastrointestinal toxicity.