The role of gastric mucosal hexosamine in aspirin-induced ulcers

Protective effects of an alcoholic extract of Kaempferia galanga L. rhizome on ethanol-induced gastric ulcer in mice

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizome of Kaempferia galanga L., a medicinal and edible Plant, was widely distributed in many Asian and African counties. It has been traditionally used to treat gastroenteritis, hypertension, rheumatism and asthma. However, there is a lack of modern pharmacology studies regarding its anti-gastric ulcer activity.

AIM OF THE STUDY

The objective of this study is to investigate the protective effects of an extract from K. galanga L. rhizome (Kge) and its active components kaempferol and luteolin on ethanol-induced gastric ulcer.

MATERIALS AND METHODS

The kge was prepared by ultrasonic-assisted extraction, and the contents of kaempferol and luteolin were determined by HPLC. The mice were randomly divided into seven groups: blank control (0.5 % CMC-Na; 0.1 mL/10 g), untreatment (0.5 % CMC-Na; 0.1 mL/10 g), Kge (100, 200 and 400 mg/kg), kaempferol (100 mg/kg) and luteolin (100 mg/kg) groups. The mice were treated intragastrically once daily for 7 days. At 1 h post the last administration, the mice in all groups except the blank control group were intragastrically administrated with anhydrous alcohol (0.1 mL/10 g) once to induce gastric ulcer. Then, fasting was continued for 1 h, followed by sample collection for evaluation by enzyme-linked immunosorbent assay and real-time reverse transcription polymerase chain reaction assay.

RESULTS

The contents of kaempferol and luteolin in Kge were determined as 3713 μg/g and 2510 μg/g, respectively. Alcohol induced severely damages with edema, inflammatory cell infiltration and bleeding, and the ulcer index was 17.63 %. After pre-treatment with Kge (100, 200 and 400 mg/kg), kaempferol and luteolin, the pathological lesions were obviously alleviated and ulcer indices were reduced to 13.42 %, 11.65 %, 6.54 %, 3.58 % and 3.85 %, respectively. In untreated group, the contents of Ca2+, myeloperoxidase, malondialdehyde, NO, cyclic adenosine monophosphate and histamine were significantly increased, while the contents of hexosamine, superoxide dismutase, glutathione peroxidase, and prostaglandin E2 were significantly decreased; the transcriptional levels of IL-1α, IL-1β, IL-6, calcitonin gene related peptide, substance P, M3 muscarinic acetylcholine receptor, histamine H2 receptor, cholecystokinin 2 receptor and H+/K+ ATPase were significantly increased when compared with the blank control group. After pre-treatment, all of these changes were alleviated, even returned to normal levels. Kge exhibited anti-gastric ulcer activity and the high dose of Kge (400 mg/kg) exhibited comparable activity to that of kaempferol and luteolin.

CONCLUSION

The study showed that K. galanga L., kaempferol, and luteolin have protective effects against ethanol-induced gastric ulcers. This is achieved by regulating the mucosal barrier, oxidative stress, and gastric regulatory mediators, as well as inhibiting the TRPV1 signaling pathway and gastric acid secretion, ultimately reducing the gastric ulcer index.

Effects of atractylodis rhizoma pharmacopuncture on an acute gastric mucosal lesion induced by compound 48/80 in rats

Objectives:

This study was designed to investigate the protective effects of Atractylodis Rhizoma pharmacopuncture (ARP) against acute gastric mucosal lesions induced by compound 48/80 in rats.

Methods:

The ARP was injected in Joksamni (ST36) and Jungwan (CV12) 1 hr before treatment with compound 48/80. The animals were sacrificed under anesthesia 3 hrs after treatment with compound 48/80. The stomachs were removed, and the amounts of gastric adherent mucus, gastric mucosal hexosamine, thiobarbituric acid reactive substances (TBARS), xanthine oxidase (XO), and superoxide dismutase (SOD) were measured. Also, histological examination were performed.

Results:

Gastric adherent mucus, gastric mucosal hexosamine and histological defects of gastric mucosa declined significantly after ARP treatment. Changes in gastric mucosal TBARS were also reduced by ARP treatment, but this result was not statistically significant. ARP treatment did not change the XO and the SOD activities.

Conclusions:

ARP showed protective effects for acute gastric mucosal lesions induced by compound 48/80 in rats. These results suggest that ARP may have protective effects for gastritis.

Effect of rebamipide on the glycosaminoglycan content of the ulcerated rat stomach

To elucidate the mechanism of the anti-ulcer effect of rebamipide (2-(4-chlorobenzoylamino)-3-[2-(1H)-quinolinon-4-yl] propionic acid), changes in glycosaminoglycan (GAG), uronic acid and hexosamine contents of stomach tissue were examined in rats treated with the ulcer-inducing agents and/or rebamipide. Uronic acid and hexosamine contents in acid hydrolysates of stomach tissue were increased after diethyldithiocarbamate (DDC, 800 mg/kg, s.c.) or histamine (300 mg/kg, i.p.) treatment, and similar changes in the GAG, uronic acid, and hexosamine levels were observed in stomach tissue extracts. Pretreatment with rebamipide (60 mg/kg, i.p.) resulted in an additional increase in the contents of the above components after DDC or histamine treatment. However, rebamipide treatment alone did not increase the gastric contents of GAG and GAG components in normal rats. Gel filtration chromatography of extracted GAGs suggested that DDC, histamine and rebamipide treatments do not cause a change in the aggregated forms of gastric GAGs. These results suggest that rebamipide stimulates the GAG synthesis in the ulcerated stomach and that this effect may contribute to the healing process of gastric ulcer.

Effect of proglumide on glycoprotein synthesis in aspirin-induced gastric erosions in rats

The effect of proglumide on the rate of incorporation of (3H)-N-acetylglucosamine into glycoproteins (GP synthesis) in the glandular stomach in normal, fasting and aspirin-treated rats was studied. GP synthesis was significantly reduced by fasting. In Donryu rats, administration of aspirin (100 mg/kg) significantly decreased GP synthesis and induced the concurrent development of gastric erosions in the corpus, but not in the antrum, where no erosion was detected. Meanwhile, in Wistar rats little or no decrease of GP synthesis was observed in the glandular stomach and only slight erosions were found in the corpus. A negative linear correlation was found between the area of erosions and GP synthesis in the corpus of Donryu rats. Pretreatment with proglumide accelerated GP synthesis in the normal glandular stomach and restored the GP decrease caused by fasting. Gastric erosions induced by aspirin were also inhibited by proglumide and the GP decrease in the corpus was prevented. These results suggest that decreased synthesis of glycoproteins may be associated with the development of erosions induced by aspirin and that proglumide may partly exert its anti-erosive activity by stimulating glycoprotein synthesis in the glandular stomach.

The activity of N-acetylglucosamine kinase in rat gastric mucosa

The activity of N-acetylglucosamine kinase in the rat glandular stomach was studied to elucidate its participation in aspirin-induced ulcers, and the effect of proglumide, an anti-ulcer agent which was found to increase gastric mucosal hexosamine, on this enzymatic activity was also studied. N-Acetylglucosamine kinase activity was found to be significantly higher in the antrum than in the corpus, the antrum being 1.3--1.9 times as active as the corpus. The mucosal layer itself was about 1.8--2.0 times as active as the whole tissue of the glandular stomach. This enzymatic activity in the glandular stomach was found to decrease slightly after fasting and to further decrease after intragastric administration of aspirin (100 mg/kg). The pylorus-ligated rats showed a significant decline of this enzymatic activity following the administration of aspirin. Acceleration of N-acetylglucosamine kinase activity with proglumide was demonstrated in vivo and in vitro experiments. Prior treatment with proglumide prevented aspirin-induced ulcers and correspondingly stimulated this enzymatic activity. These results suggest that the activity of N-acetylglucosamine kinase in the rat glandular stomach closely parallels the distribution and localization of gastric hexosamine, glycosaminoglycans, and glycoproteins. A decrease of this enzymatic activity correlates with the production of ulcers by aspirin. The mechanism by which proglumide increases gastric hexosamine is at least partly attributed to the activation of N-acetylglucosamine kinase in the glandular stomach.