The effect of laser irradiation on oxazolone-induced ulcerative colitis / 中华物理医学与康复杂志

ABSTRACT

Objective To observe any therapeutic effect of laser irradiation on pathological inflammatory reactions in ulcerative colitis (UC) induced by oxazolone,and to investigate possible mechanisms.Methods Six rats were selected as a normal control group.Another 24 rats with UC induced by oxazolone were randomly assigned to a UC model group (n =8),a 400 mW laser group (161.3 mW/cm2,n =8),and a 200 mW laser group (80.6 mW/cm2,n =8).All the rats were fixed in custom-built devices.Those in the therapy groups were treated daily,10 min per time,for 10 days.After the end of the last irradiation session,disease activity indexes (DAIs)were observed.Rats from every group were sacrificed 24 h after the last irradiation in order to observe any pathological changes in colon tissue,the weight of fresh ulcerated tissues,and gross changes in morphology.Colon segments were stained with hematoxylin-eosin and histological lesion scoring was performed under a light microscope.Any changes in inflammatory edema in the colonic mucous membrane were observed before and after laser irradiation.Results The UC model was successfully established.Average body weight in the 400 mW laser group increased significantly more than in the UC model group,approaching that of the normal control group.DAI decreased significantly.The thickness of the epithelial mucous membrane,lamina propria and submucosa was basically restored.Histological lesion scores also improved significantly,and the weight of fresh ulcerative tissue was significantly lower.Mucous membrane ulcers,submucosa edema and inflammatory cell infiltration all were alleviated significantly,merely presenting a few inflamed cells and small amounts of periphlebitis.In the 200 mW laser group all these outcome measures improved significantly compared with the UC model group,but were not as good as in the 400 mW laser group,and the rats needed longer to recover.Conclusion Laser irradiation at 400 mW has advantages over 200 mW,and could significantly relieve the pathological inflammatory response in colonic tissue,decrease submucosa edema and ameliorate other symptoms of ulcerative colitis,at least in rats.