Phototherapy with artificial light suppresses dextran sulfate sodium-induced colitis in a mouse model.
OBJECTIVE
Medical treatment for inflammatory bowel disease (IBD) requires chronic administration and causes side effects. Recently, anti-inflammatory effects of phototherapy were reported in animal models. The present study evaluated whether phototherapy improves dextran sulfate sodium (DSS)-induced colitis in a mouse model of IBD.


METHODS
Mice were divided into four equal groups: Control, DSS, DSS + light low (LL), and DSS + light high (LH) groups. Normal fluorescent light intensity in the Control and DSS groups was 200 lux. Artificial light intensities were as follows: DSS + LL group, 1000 lux; DSS + LH group, 2500 lux. After administering phototherapy for 7 days, we evaluated disease activity index (DAI), histological score, colon length/weight, serum 1,25-dihydroxyvitamin D(3) level, and serum and colonic cytokines in the mice.


RESULTS
DAI and histological scores were significantly lower in the DSS + LL group than in the DSS group (both, P < 0.05). Colon length and weight were significantly higher in the DSS + LL group than in the DSS group (both, P < 0.05). Serum interleukin (IL)-6, TNF-α, and IL-17 in the DSS + LL group were significantly lower, and serum and colonic IL-10 were significantly higher in the DSS + LL group than in the DSS group (all, P < 0.05). Serum 1,25-dihydroxyvitamin D(3) levels in the DSS + LH group were significantly increased compared with those in the DSS + LL and DSS groups.


CONCLUSIONS
Artificial light phototherapy suppressed DSS-induced colitis in mice by suppression of pro-inflammatory cytokines and promotion of anti-inflammatory cytokines.
Department of Gastroenterological and Pediatric Surgery, Oita University Faculty of Medicine, Oita, Japan.
Takahiro
T
Hiratsuka
Masafumi
M
Inomata
Shigeru
S
Goto
Yoshimasa
Y
Oyama
Toshiaki
T
Nakano
Chao-Long
CL
Chen
Norio
N
Shiraishi
Takayuki
T
Noguchi
Seigo
S
Kitano
D000818:Animals; D015415:Biomarkers / Q000032:analysis / Q000097:blood; D002117:Calcitriol / Q000097:blood; D003092:Colitis / Q000139:chemically induced* / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D016264:Dextran Sulfate / Q000633:toxicity; D004195:Disease Models, Animal; D004307:Dose-Response Relationship, Radiation; D018836:Inflammation Mediators / Q000032:analysis / Q000097:blood; D016753:Interleukin-10 / Q000032:analysis / Q000097:blood; D015850:Interleukin-6 / Q000097:blood; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010789:Phototherapy / Q000379:methods*; D012720:Severity of Illness Index; D013997:Time Factors; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000097:blood
D015415:Biomarkers; D018836:Inflammation Mediators; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D016264:Dextran Sulfate; D002117:Calcitriol
IL-10; inflammatory bowel disease; phototherapy