Protective effect of Korean Red Ginseng extract against Helicobacter pylori-induced gastric inflammation in Mongolian gerbils

Abstract

Helicobacter pylori-induced gastric inflammation includes induction of inflammatory mediators interleukin (IL)-8 and inducible nitric oxide synthase (iNOS), which are mediated by oxidant-sensitive transcription factor NF-κB. High levels of lipid peroxide (LPO) and increased activity of myeloperoxidase (MPO), a biomarker of neutrophil infiltration, are observed in H. pylori-infected gastric mucosa. Panax ginseng Meyer, a Korean herb medicine, is widely used in Asian countries for its biological activities including anti-inflammatory efficacy. The present study aims to investigate whether Korean Red Ginseng extract (RGE) inhibits H. pylori-induced gastric inflammation in Mongolian gerbils. One wk after intragastric inoculation with H. pylori, Mongolian gerbils were fed with either the control diet or the diet containing RGE (200 mg RGE/gerbil) for 6 wk. The following were determined in gastric mucosa: the number of viable H. pylori in stomach; MPO activity; LPO level; mRNA and protein levels of keratinocyte chemoattractant factor (KC, a rodent IL-8 homolog), IL-1β, and iNOS; protein level of phospho-IκBα (which reflects the activation of NF-κB); and histology. As a result, RGE suppressed H. pylori-induced mRNA and protein levels of KC, IL-1β, and iNOS in gastric mucosa. RGE also inhibited H. pylori-induced phosphorylation of IκBα and increases in LPO level and MPO activity of gastric mucosa. RGE did not affect viable H. pylori colonization in the stomach, but improved the histological grade of infiltration of polymorphonuclear neutrophils, intestinal metaplasia, and hyperplasia. In conclusion, RGE inhibits H. pylori-induced gastric inflammation by suppressing induction of inflammatory mediators (KC, IL-1β, iNOS), MPO activity, and LPO level in H. pylori-infected gastric mucosa.

Keywords: Helicobacter pylori; Korean Red Ginseng extract; Mongolian gerbil; gastric inflammation.

Fig. 1

Effect of Korean Red Ginseng extract (RGE) on viable Helicobacter pylori colonization in stomach and stomach weight of Mongolian gerbils. (A) Viable cell numbers of H. pylori are determined and expressed as colony forming units (CFU)/g tissue. (B) Stomach weight to body weight ratio at the end of the experiment. None, animals without H. pylori infection that were fed the control diet; H. pylori control, animals with H. pylori infection that were fed the control diet; and H. pylori + RGE, animals with H. pylori infection that were fed a diet supplemented with RGE. *p < 0.05 versus none. **p < 0.05 versus H. pylori control.

Fig. 2

Effect of Korean Red Ginseng extract (RGE) on Helicobacter pylori-induced histological changes in gastric mucosal regions of Mongolian gerbils. (A) Gastric mucosal sections stained with hematoxylin and eosin. Microscopic images were obtained at magnification of ×200. (B) The inflammatory responses of gastric mucosa were graded according to morphologic criteria: Grade 0, normal; Grade 1, mild; Grade 2, moderate; and Grade 3, severe. The following characteristics of gastric lesions were recorded: polymorphonuclear leukocytes (PMNs) infiltration, chronic inflammation such as mononuclear cells infiltration and lymphoid nodules formation, intestinal metaplasia, and hyperplasia and formation of heterotopic proliferative glands. None, animals without H. pylori infection that were fed the control diet; H. pylori control, animals with H. pylori infection that were fed the control diet; and H. pylori + RGE, animals with H. pylori infection that were fed a diet supplemented with RGE. *Statistically significant difference (p < 0.05) between H. pylori control and H. pylori + RGE.

Fig. 3

Effect of Korean Red Ginseng extract (RGE) on Helicobacter pylori-induced increases in myeloperoxidase (MPO) activity and lipid peroxide (LPO) level in gastric mucosal tissues of Mongolian gerbils. (A) The MPO activity in the gastric mucosal tissues is expressed as units/mg protein. (B) LPO levels were measured as thiobarbituric acid reactive substances and are expressed as pg/mg protein. None, animals without H. pylori infection that were fed the control diet; H. pylori control, animals with H. pylori infection that were fed the control diet; and H. pylori + RGE, animals with H. pylori infection that were fed a diet supplemented with RGE. *p < 0.05 versus none. **p < 0.05 versus H. pylori control.

Fig. 4

Effect of Korean Red Ginseng extract (RGE) on Helicobacter pylori-induced mRNA expression of keratinocyte chemoattractant factor (KC), interleukin (IL)-1β, and inducible nitric oxide synthase (iNOS), in gastric mucosal tissues of Mongolian gerbils. Real-time quantitative RT-PCR was performed on reverse-transcribed RNA isolated from gastric mucosa. mRNA level of (A) KC, (B) IL-1β, and (C) iNOS was normalized to β-actin. None, animals without H. pylori infection that were fed the control diet; H. pylori control, animals with H. pylori infection that were fed the control diet; and H. pylori + RGE, animals with H. pylori infection that were fed a diet supplemented with RGE. *p < 0.05 versus none. **p < 0.05 versus H. pylori control.

Fig. 5

Effect of Korean Red Ginseng extract (RGE) on protein levels of, keratinocyte chemoattractant factor (KC), inducible nitric oxide synthase (iNOS), phospho-specific form of IκBα, and IκBα in Helicobacter pylori-infected gastric mucosal tissues of Mongolian gerbils. (A) The levels of KC in gastric mucosal tissues, as measured by enzyme linked immunosorbent assay. (B) iNOS, phospho-IκBα, IκBα, and actin protein levels in gastric mucosal tissues, as determined by Western blotting. Two representative bands per group are shown. None, animals without H. pylori infection that were fed the control diet; H. pylori control, animals with H. pylori infection that were fed the control diet; and Experimental and epidemiological evidence on non-organ specific cancer preventive effect of Korean ginseng and identification of active compounds H. pylori + RGE, animals with H. pylori infection that were fed a diet supplemented with RGE.