Interleukin-1 receptor antagonist reduced apoptosis and attenuated intestinal mucositis in a 5-fluorouracil chemotherapy model in mice.
OBJECTIVE
The aim of this study was to investigate the relationship between changes in IL-1β expression and intestinal apoptosis after chemotherapy. And we further determine whether interleukin-1 receptor antagonist (IL-1Ra) reduces apoptosis in vivo after 5-fluorouracil (5-FU) chemotherapy in the small intestine.


METHODS
Intestinal mucositis was induced in mice by intraperitoneal injection of a single dose of 5-FU (200 mg/kg). IL-1Ra (1 mg/kg) was injected subcutaneously twice daily after 5-FU injection. 5-FU-induced intestinal apoptosis was detected by TUNEL assay. The expression of IL-1β induced by 5-FU in local intestinal tissue was examined by RT-PCR and immunohistochemistry. Assessment of 5-FU-induced mucositis (histology, diarrhea scores, bowel weight) was performed. The apoptosis-related proteins were investigated by western blotting analysis. The proliferation of intestine was examined by immunohistological staining of PCNA. Viability of IEC-6 cells was determined using the CCK-8 assay. The apoptosis of IEC-6 cells was examined by Hoechst 33342 staining.


RESULTS
The variation of IL-1β expression induced by 5-FU was in accordance with the changes in intestinal apoptosis. Administration of IL-1Ra could block the destructive effect of IL-1β and reduce apoptosis in the small intestinal crypt after chemotherapy. The protection against apoptosis was in accordance with the reduction of the up-regulation of Bax and caspase 3 and the elimination of the down-regulation of Bcl-2 and Bcl-xL. Moreover, IL-1Ra attenuated the severity of intestinal mucositis induced by 5-FU and enhanced intestinal crypt proliferation. In vitro experiments showed that IL-1Ra suppressed apoptosis and increased cell viability in enterocyte IEC-6 cells treated with 5-FU. Additionally, IL-1Ra did not affect the chemotherapeutic effect of 5-FU in tumor CT-26 xenograft mice.


CONCLUSIONS
Our studies elucidate that IL-1β is quite possibly involved in and mediated the course of intestinal apoptosis after 5-FU chemotherapy. Administered with IL-1Ra protects mice against intestinal apoptosis induced by 5-FU, relieves mucosal impairment of the small intestine, and facilitates the recovery of the intestinal mucosa. IL-1Ra treatment offers a novel promising strategy for the prevention and cure of chemotherapy-induced intestinal mucositis in clinical practice.
Wu
Zhen-Qian
ZQ
Department of Surgery, The Sixth People's Hospital Affiliated to Shanghai Jiao Tong University, 600 Yishan Road, 200233 Shanghai, China.
Han
Xiao-Dong
XD
Wang
Yu
Y
Yuan
Ke-Li
KL
Jin
Zhi-Ming
ZM
Di
Jian-Zhong
JZ
Yan
Jun
J
Pan
Ye
Y
Zhang
Pin
P
Huang
Xin-Yu
XY
Wang
Zhi-Gang
ZG
Zheng
Qi
Q
D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000009:adverse effects* / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects*; D001562:Benzimidazoles / Q000008:administration & dosage; D003967:Diarrhea / Q000139:chemically induced / Q000188:drug therapy; D004195:Disease Models, Animal; D005456:Fluorescent Dyes / Q000008:administration & dosage; D005472:Fluorouracil / Q000009:adverse effects*; D006801:Humans; D053590:Interleukin 1 Receptor Antagonist Protein / Q000009:adverse effects / Q000235:genetics / Q000627:therapeutic use*; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000473:pathology; D007422:Intestines / Q000187:drug effects; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D052016:Mucositis / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology
D000964:Antimetabolites, Antineoplastic; D001562:Benzimidazoles; D005456:Fluorescent Dyes; D053590:Interleukin 1 Receptor Antagonist Protein; C017807:bisbenzimide ethoxide trihydrochloride; D005472:Fluorouracil