Cytotoxic therapy leads to marked changes in intestinal structure, function, immunity and microbiota. Information about chemotherapy-induced intestinal gene expression may provide insights into the mechanisms underlying gut toxicity, and help to identify biomarkers and targets for intervention. We investigated jejunal tissue from piglets subjected to two different, clinically-relevant chemotherapy regimens, 1) busulfan plus cyclophosphamide (BUCY) and 2) doxorubicin (DOX). Gene expression analysis identified 1328 and 594 differentially expressed genes in the BUCY and DOX pigs, compared with their respective controls. Similar changes in expression patterns across BUCY and DOX piglets were found for 137 genes (95 genes repressed and 42 induced). Selected genes of potential biological significance were confirmed by real-time polymerase chain reaction. Key innate defense molecules, including surfactant protein-D (SP-D), deleted in malignant brain tumors 1 (DMBT-1) and peptidoglycan recognition protein 2 (PGLYRP2) were among the up-regulated genes for both chemotherapy treatments. Based on the results from the two different treatments, we conclude that chemotherapy induces reduced intestinal adaptive immunity while innate immune functions involved in surveillance, protection and homeostasis of mucosal surfaces are up-regulated. The results may be of value to understand monitor and prevent chemotherapy-induced intestinal mucositis by dietary or medical interventions.
Overall design: Twenty-two three day-old crossbred SPF piglets (Large White × Danish Landrace) were used for the experiments. All pigs were delivered to our research facilities after having suckled their mother from birth. The pigs were housed in individual cages and kept in an environmentally controlled room (12/12 light/dark rhythm, ~30 °C). The studies were carried out in accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. The protocol was approved by the National Committee on Animal Experimentation (approval number: 2010/561-1760). The manuscript was prepared in accordance to the ARRIVE guidelines for reporting animal research (32). The tissues used for the analyses originated from two separate studies on chemotherapy-induced GI toxicity in piglets. One experiment was based on treatment with a combination of busulfan and cyclophosphamide (BUCY) (26) while another experiment was based on a single dose of the topoisomerase II inhibitor, doxorubicin (DOX) (33). For all details regarding the clinical condition of the piglets and organ and physiological responses to chemotherapy, we refer the reader to these publications (26, 33). Prior to cytotoxic treatment pigs were anesthetized and fitted with orogastric tubes (6F Portex, Kent, UK) and a catheter (Tygon OD 0.070 ID 0.040 Saint-Gobain Performance Plastics, France) inserted in the external jugular vein for blood sampling and administration of drugs and fluids. Surgery was performed under zoletil mix anesthesia (i.m. tiletamine, 0.28 mg/kg; zolazepam, 0.28 mg/kg; xylazine, 0.56 mg/kg; ketamine, 0.56 mg/kg; butorphanol, 0.11 mg/kg). All animals were anesthetized and euthanized by an intracardial injection of sodium pentobarbital (200 mg/kg). Chemotherapeutic drugs were administered intravenously (i.v.) via the jugular vein catheter.
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