Abstract: Objective To study the treatment effects of polysaccharides from radix bletillae on ulcerative colitis (UC) rats from the perspectives of inflammatory reaction and oxidative stress. Methods Rats were randomly divided into control group, model group (constructed by enema with 0.8 mL, 2.5 mg/mL trinitrobenzene sulfonic acid containing 50% ethanol), mesalazine group (10 mL/kg) and low, medium and high dose of radix bletillae groups (100, 200 and 400 mg/kg) constructed by enema with 0.8 mL trinitrobenzene sulfonic acid (2.5 mg/mL) containing 50% ethanol in the intervention groups. After 2 days, rats were given intragastric administration for 10 days. The disease activity index (DAI) of each group was observed. The levels of IL-1β, IL-10 and TNF-α in serum were detected by ELISA, and the mRNA expressions of IL-1β, IL-10 and TNF-α in colon tissue were detected by RT-qPCR. SOD, MDA and GSH-Px in colon tissue were measured by kits. The protein expression of TLR-4 and NF-κB p65 in colon tissue were detected by Western blot. Results Compared with the control group, the weight of rats in the model group decreased, DAI score, IL-1β and TNF-α expression all increased, IL-10, SOD and GSH-Px activity in colon tissue decreased, MDA content and protein expression of TLR-4 and NF-κB p65 increased (P＜0.05). Compared with the model group, the DAI score, the expression of IL-1β and TNF-α decreased, while IL-10 increased in the low, medium and high dose of of radix bletillae group. SOD and GSH-Px activity in colon tissue increased, while MDA content and protein expression of TLR-4 and NF-κB p65 decreased in a dose-dependent manner (P＜0.05). Conclusions Polysaccharides of radix bletillae have the preferably treatment effect on UC rats, the mechanism may be related to the inhibition of inflammatory reaction and alleviation of oxidative stress.

Key words: polysaccharides of radix bletillae, ulcerative colitis, inflammatory reaction, oxidative stress