title: Intestinal bacteria are necessary for doxorubicin-induced intestinal damage but not for doxorubicin-induced apoptosis.
abstract: Doxorubicin (DOXO) induces significant, but transient, increases in apoptosis in the stem cell zone of the jejunum, followed by mucosal damage involving a decrease in crypt proliferation, crypt number, and villus height. The gastrointestinal tract is home to a vast population of commensal bacteria and numerous studies have demonstrated a symbiotic relationship between intestinal bacteria and intestinal epithelial cells (IEC) in maintaining homeostatic functions of the intestine. However, whether enteric bacteria play a role in DOXO-induced damage is not well understood. We hypothesized that enteric bacteria are necessary for induction of apoptosis and damage associated with DOXO treatment. Conventionally raised (CONV) and germ free (GF) mice were given a single injection of DOXO, and intestinal tissue was collected at 6, 72, and 120 h after treatment and from no treatment (0 h) controls. Histology and morphometric analyses quantified apoptosis, mitosis, crypt depth, villus height, and crypt density. Immunostaining for muc2 and lysozyme evaluated Paneth cells, goblet cells or dual stained intermediate cells. DOXO administration induced significant increases in apoptosis in jejunal epithelium regardless of the presence of enteric bacteria; however, the resulting injury, as demonstrated by statistically significant changes in crypt depth, crypt number, and proliferative cell number, was dependent upon the presence of enteric bacteria. Furthermore, we observed expansion of Paneth and goblet cells and presence of intermediate cells only in CONV and not GF mice. These findings provide evidence that manipulation and/or depletion of the enteric microbiota may have clinical significance in limiting chemotherapy-induced mucositis.
authors.affiliation: a Faculty of Health and Medicine, Lancaster University , Lancaster , United Kingdom.
authors.forename: Rachael J
authors.initials: RJ
authors.lastname: Rigby
authors.affiliation: b Department of Surgery , University of North Carolina , Chapel Hill , North Carolina , USA.
authors.forename: Jacquelyn
authors.initials: J
authors.lastname: Carr
authors.affiliation: c Department of Pediatrics , University of North Carolina , Chapel Hill , North Carolina , USA.|d Department of Cell Biology and Physiology , University of North Carolina , Chapel Hill , North Carolina , USA.
authors.forename: Kelly
authors.initials: K
authors.lastname: Orgel
authors.affiliation: e Department of Molecular Biomedical Sciences , NC State University , Raleigh , North Carolina , USA.
authors.forename: Stephanie L
authors.initials: SL
authors.lastname: King
authors.affiliation: d Department of Cell Biology and Physiology , University of North Carolina , Chapel Hill , North Carolina , USA.
authors.forename: P Kay
authors.initials: PK
authors.lastname: Lund
authors.affiliation: b Department of Surgery , University of North Carolina , Chapel Hill , North Carolina , USA.|e Department of Molecular Biomedical Sciences , NC State University , Raleigh , North Carolina , USA.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Dekaney
mesh_terms: D000818:Animals; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000009:adverse effects*; D017209:Apoptosis / Q000187:drug effects*; D001419:Bacteria / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D004317:Doxorubicin / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D000069196:Gastrointestinal Microbiome / Q000187:drug effects*; D005856:Germ-Free Life; D020397:Goblet Cells / Q000187:drug effects / Q000382:microbiology; D007422:Intestines / Q000166:cytology / Q000187:drug effects* / Q000382:microbiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D019879:Paneth Cells / Q000187:drug effects / Q000382:microbiology
chemical_list: D000903:Antibiotics, Antineoplastic; D004317:Doxorubicin
keywords: apoptosis; bacteria; damage; doxorubicin; germ free; intestine