Glycyrrhiza Polysaccharide Alleviates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Mice

Abstract

Background: Licorice is one of the most ubiquitous herbs in traditional Chinese medicine, with notable anti-inflammatory and antiulcerative effects as well as potent digestive disease therapeutic impacts; yet, its active components and mechanisms remain unclear. There is a lot of evidence that Glycyrrhiza polysaccharide (GPS) has antioxidants, improving intestinal flora, anti-inflammatory effects, etc. Hypothesis/Purpose. Here, we investigated the effects of GPS on dextran sulfate sodium (DSS)-induced acute ulcerative colitis (UC) mice and its possible mechanisms.

Methods: GPS (100, 200, and 400 mg/kg) or the positive control drug sulfasalazine (SASP) (200 mg/kg) were orally administered to mice for 8 days. Body weight was recorded daily. Symptoms associated with UC, such as disease activity index (DAI), colon length, spleen weight, and mucosal damage were detected. The possible mechanism of GPS ameliorating enteritis symptoms was explored by detecting intestinal permeability and serum levels of inflammatory factors, and changes in intestinal permeability were expressed by serum concentration of FITC-dextran and D-lactic acid.

Results: The results demonstrated that GPS administration alleviated UC symptoms in colitis mice, including weight loss, DAI index, shorting colon length, and mucosal damage. Mechanistic evaluation revealed that GPS treatment reduced intestinal permeability and serum levels of inflammatory factors: IL-1, IL-6, and TNF-α, while increasing serum levels of the anti-inflammatory factor IL-10, suggesting that GPS's mechanism in UC is related to reducing intestinal permeability and inhibiting the inflammatory response, with intestinal permeability implicated as the initiating mechanism.

Conclusion: This study highlights GPS as a promising therapeutic agent, with high therapeutic efficacy and a good safety profile, for enteritis and beyond.

Figure 1

Effects of GPS on DAI scores in UC mice (n = 10). ^★★p < 0.01 vs. normal control; ^##p < 0.01 vs. model; ^●●p < 0.01 vs. SASP. NC: normal group; SASP: positive drug group; Model: model group; GPS: Glycyrrhiza polysaccharide group.

Figure 2

Effects of GPS on body weight changes in UC mice (n = 10). NC: normal control group; SASP: positive drug group; Model: model group; GPSH: high dose of GPS group; GPSM: middle dose of GPS group; GPSL: low dose of GPS group.

Figure 3

Effects of GPS on colon length of UC mice (n = 10). ^★★p < 0.01 vs. normal control; ^##p < 0.01 vs. model. NC: normal group; SASP: positive drug group; Model: model group; GPS: Glycyrrhiza polysaccharide group.

Figure 4

Effects of GPS on spleen weight in UC mice (n = 10). ^∗p< 0.05 vs. normal control; ^▲p < 0.05 vs. Model. NC: normal group; SASP: positive drug group; Model: model group; GPS: Glycyrrhiza polysaccharide group.

Figure 5

GPS treatment ameliorated mucosal damage of UC mice. (a) Microscopic images of the colon (×100). (b) Histopathological score of mucosal damage in UC mice treated with GPS (n = 7). ^∗∗p < 0.01 vs. NC; ^▲▲p < 0.01 vs. Model. NC: normal group; SASP: positive drug group; Model: model group; GPS: Glycyrrhiza polysaccharide group.

Figure 6

Effects of GPS on FITC-dextran concentration in UC mice (n = 10). ^◆◆p < 0.01, ^∗∗p < 0.01 vs. normal control; ^##p < 0.01 vs. Model; ^●●p < 0.01 vs. SASP. NC: normal group; SASP: positive drug group; Model: model group; GPS: Glycyrrhiza polysaccharide group.

Figure 7

Effects of GPS on D-LAC concentration in UC mice (n = 10). p < 0.01 vs. normal control; ^▲▲p < 0.01 vs. Model; ^●p < 0.05 vs. SASP. NC: normal group; SASP: positive drug group; Model: model group; GPS: Glycyrrhiza polysaccharide group.

Figure 8

Effects of GPS on the levels of IL-1 (a), IL-6 (b), TNF-α (c), and IL-10 (d) in UC mice (n = 10). ^★★p < 0.01 vs normal control; ^▲p < 0.05; ^▲▲p < 0.01 vs. model. NC: normal group; SASP: positive drug group; Model: model group; GPS: Glycyrrhiza polysaccharide group.