Protective effect of DA-9601, an extract ofArtemisiae Herba, against naproxen-induced gastric damage in arthritic rats

Gastrointestinal irritation is the most frequent adverse effect in patients chronically taking nonsteroidal antiinflammatory drugs (NSAIDs) for the treatment of arthritic conditions. Gastroprotective effect of DA-9601, a new antiulcer agent fromArtemisiae Herba extract, against NSAID was evaluated in a rat model of arthritis that is similar in many aspects to human rheumatoid arthritis. Daily oral dosing of naproxen (30 mg/kg), one of the most commonly used NSAID, induced apparent gastric lesions as well as a significant decrease in mucosal prostaglandin E(2) (PGE(2)) and prostaglandin F(1alpha) (PGF(1alpha)) levels. Coadministration of DA-9601 prevents naproxen-induced mucosal injury and depletion, of prostaglandins, in a dose-related manner. DA-9601 did not alter the antiinflammatory or analgesic effect of naproxen. The present results suggest that DA-9601 may be useful as a mucoprotectant against NSAIDs in clinical practice.

Impact on Prognosis of Lymph Node Micrometastasis and Isolated Tumor Cells in Stage II Colorectal Cancer

Purpose

Even though the importance of micrometastases (MMS) and isolated tumor cells (ITC) has been brought up by many physicians, its impact on the prognosis in stage II colorectal cancer is uncertain. In this research, we tried to investigate the clinical features of MMS and ITC and to prove any correlation with prognosis.

Methods

The research pool was 124 colorectal cancer patients who underwent a curative resection from April 2005 to November 2009. A total of 2,379 lymph nodes (LNs) were examined, and all retrieved LNs were evaluated by immunohistochemical staining with anti-cytokeratin antibody panel. Clinicopathologic parameters and survival rates were compared based on the presence of MMS or ITC and on the micrometastatic lymph node ratio (mmLNR), which is defined as the number of micrometastatic LNs divided by the number of retrieved LNs.

Results

Out of 124 patients (26.6%) 33 were found to have MMS or ITC. There were no significant differences in clinicopathologic features, such as gender, tumor location and size, depth of invasion, histologic grade, except for age (P = 0.04). The three-year disease-free survival rate for the MMS or ITC positive group was 85.7%, and that for MMS and ITC negative group was 92.8% (P = 0.209). The three-year disease-free survival rate for the mmLNR > 0.25 group was 73.3%, and that for the mmLNR ≤ 0.25 group was 92.9% (P = 0.03).

Conclusion

The presence of MMS or ITC was not closely correlated to the prognosis. However, mmLNR is thought to be a valuable marker of prognosis in cases of stage II colorectal cancer.

Long-term evaluation of mice model infected with Helicobacter pylori: focus on gastric pathology including gastric cancer

BACKGROUND

Long-term evaluation of gastric pathology after H. pylori infection is very important in order to reveal its clinical implications, since debate still exists on the gastric carcinogenesis provoked by H. pylori infection in animal models.

AIM

Either to evaluate the long-term outcome of H. pylori infection or to determine how H. pylori could provoke gastric cancer in the mice model.

METHODS

Four-week-old specific pathogen free C57BL/6 mice (n = 115) were infected with SS1, the mouse-adapted H. pylori strain. After 4, 8, 16, 24, 36, 50 and 80 weeks of bacterial infection, the H. pylori-infected mice were sacrificed.

RESULTS

After 80 weeks of infection, almost all the H. pylori-infected mice developed hyperplastic gastritis, but did not show any evidence of gastric adenoma, dysplasia or carcinoma. PCNA positive cells were most abundant after 50 weeks and tended to decrease thereafter up to 80 weeks, whereas apoptosis began to be noted 8 weeks after H. pylori infection, showing 7-8 apoptotic cells/high power field, and tending to increase as time passed. Normally observed neutral mucin decreased during the experiment, showing the most marked decrease 50 weeks after H. pylori infection. In contrast, acidic mucin was noted from 50 weeks after infection.

CONCLUSION

The SS1-infected mouse seems to be a suitable animal model for H. pylori-related research, and H. pylori itself does not induce gastric cancer in normal wild-type mouse model following long-term exposure, which could be explained by the balance that exists between cell proliferation and apoptosis.

Conditional loss of TGF-beta signalling leads to increased susceptibility to gastrointestinal carcinogenesis in mice

BACKGROUND

Downregulation of TGF-beta receptors is implicated in colon cancer development. Inactivation of either of the two transmembrane serine/threonine kinases, TGF-beta1 types I/II receptors, is now implicated in carcinogenesis, especially gastrointestinal carcinogenesis.

METHODS

We generated transgenic mice, called pS2-dnRII or ITF-dnRII, of which the dominant negative mutant of the TGF-beta type II receptor was expressed under the control of tissue-specific promoters, the pS2 promoter for stomach and ITF for intestine. They were either infected with H.pylori (ATCC 43504 strain, CagA+ and VacA+) or administered with azoxymethane to determine the significance of loss of TGF-beta signalling in gastrointestinal carcinogenesis.

RESULTS

Gastric adenocarcinoma developed in pS2-dnRII mice, whereas only chronic active gastritis was noted in wild-type littermates after 36 weeks of H.pylori infection. Mice lacking in TGF-beta signalling specifically in the stomach showed a significantly higher proliferation cell nuclear antigen-labelling index when infected with H.pylori than wild-type littermates (P < 0.01). Development of colonic aberrant crypt foci was provoked in mice by intraperitoneal injections of azoxymethane, and ITF-dnRII mice showed significantly higher incidences of ACF and colon cancers than wild-type littermates.

CONCLUSIONS

Maintaining normal TGF-beta signalling in the gastrointestinal tract seems to be important either for preventing abnormal mucosal proliferation, or for suppressing or retarding carcinogenesis.

Involvement of oxidative stress in experimentally induced reflux esophagitis and Barrett's esophagus: clue for the chemoprevention of esophageal carcinoma by antioxidants

Oxidative damage has long been related to mucosal damages of gastrointestinal tracts and their ensuing carcinogenesis. In spite of treatment with anti-secretory medications for reflux esophagitis, considerable portions of patient did not achieve the complete mucosal healings or suffered from sustaining symptoms or development of dread complication like Barrett's esophagus, suggesting other damaging factors or impaired mucosal resistance are also involved in their pathogenesis. The present study was designed either to evaluate the oxidative stress as the major pathogenic factor of reflux esophagitis or to find out the usefulness of antioxidant in the treatment of reflux esophagitis and the prevention of development of Barrett's esophagus. Acute or chronic reflux esophagitis was induced through either narrowing the third portion of duodenal lumen or performing myotomy of lower esophageal sphincter in rats, respectively. DA-9601, a new phytopharmaceutical possessing antioxidative properties, significantly attenuated the gross and histopathologic scores of acute reflux esophagitis in a dose-dependent manner compared to those treated with ranitidine alone. Only scattered erosions were observed in antioxidant pre-treated group, but acid suppression by ranitidine was not so effective in decreasing the severity of reflux esophagitis. Significantly increased amounts of malondialdehyde (MDA), increased NF-kappa B activations, and depletions of reduced glutathione (GSH) were observed in experimentally induced reflux esophagitis, but DA-9601 pre-treatment attenuated the decrement of mucosal GSH levels and decreased MDA formations significantly. DA-9601 treatment showed significant reductions in the activation of NF-kappa B transcription factor. DA-9601 significantly decreased the proliferating cell nuclear antigen-labeling index (PCNA-LI) of esophagus (P<0.05) in chronic reflux esophagitis model and prevented the development of Barrett's esophagus. In conclusion, reflux esophagitis provoked considerable levels of oxidative stress in the esophageal mucosa. Antioxidant treatment seems to be the first line therapeutics in the prevention or treatment of reflux esophagitis. Moreover, antioxidant possibly played the chemopreventive role through preventing the development of Barrett's esophagus.

Oxidative stress is more important than acid in the pathogenesis of reflux oesophagitis in rats

BACKGROUND

Although antisecretory medications such as histamine type II receptor antagonists or proton pump inhibitors have been used to treat reflux oesophagitis, a considerable number of patients do not achieve complete mucosal healing or suffer from either sustained symptoms or ensuing complications, suggesting other damaging factors or impaired mucosal resistance are also involved in the pathogenesis of reflux oesophagitis.

AIMS

The present study was designed to evaluate oxidative stress as the major pathogenic factor of reflux oesophagitis and to determine the usefulness of antioxidants in the treatment of reflux oesophagitis.

MATERIALS AND METHODS

Reflux oesophagitis was induced by insertion of a 3 mm calibre ring into the duodenum, 1 cm distal to the ligament of Treitz, in Sprague-Dawley rats.

RESULTS

DA-9601, a novel antioxidant substance, significantly attenuated the gross and histopathological scores of reflux oesophagitis compared with those treated with ranitidine alone or reflux oesophagitis controls in a dose dependent manner. Only scattered erosions were observed in the antioxidant pretreated group but acid suppression by ranitidine was not effective in decreasing the severity of reflux oesophagitis. Significantly increased amounts of malondialdehyde (MDA), increased nuclear factor kappaB (NFkappaB) activation, and depletion of reduced glutathione (GSH) were observed in experimentally induced reflux oesophagitis. DA-9601 pretreatment attenuated the decrement in mucosal GSH levels and decreased MDA formation significantly. DA-9601 treatment caused significant reductions in activation of NFkappaB transcription factor, especially the p50 subunit, in accordance with the significantly higher levels of inhibitory protein of NFkappaB expression.

CONCLUSION

Reflux oesophagitis caused considerable levels of oxidative stress in the oesophageal mucosa and antioxidant treatment should be considered as supplementary therapy in the prevention or treatment of reflux oesophagitis with acid suppression.

Effects of taurine on cerulein-induced acute pancreatitis in the rat

Taurine, or 2-aminoethane sulfonic acid, is an intracellular amino acid and has been suggested to have a function in protecting biological systems from oxidative tissue damage. The aim of this study was to determine the effect of taurine against cerulein-induced acute pancreatitis in rats. Acute pancreatitis was induced by administering three subcutaneous injections of cerulein (40 microg/kg body weight) at 1-hour intervals, while taurine was administered intravenously at graded doses (30, 100, or 300 mg/kg, respectively) following the first cerulein injection. The severities of pancreatitis and lung injury were determined by measuring biochemical parameters, tissue myeloperoxidase (MPO), and histological changes. To clarify the mechanism of taurine, serum IL-1beta and TNF-alpha levels and tissue concentrations of malondialdehyde (MDA) were evaluated. In cerulein-induced acute edematous pancreatitis, treatment with taurine significantly decreased hyperamylasemia, tissue MPO, pancreatic edema, and the extent of pancreatic and pulmonary injury. Taurine decreased MDA concentration in the pancreas and lung, but not the serum cytokine concentration. We would conclude that taurine has beneficial effects in cerulein-induced acute pancreatitis and lung injuries by preventing the production of oxygen free radicals.

Efficacy of use of colonoscopy in dextran sulfate sodium induced ulcerative colitis in rats: the evaluation of the effects of antioxidant by colonoscopy

The goals in developing animal models of inflammatory bowel disease (IBD) are to determine the underlying mechanisms and the action of currently available drugs and to evaluate the value of new therapeutic approaches. Because of the difficulty in determining the severity of colitis in living animals, it has been necessary to kill the experimental animals at varying stages in the studies. If colonoscopic evaluation or endoscopic biopsy is feasible in these experimental animals, continuous observations could be possible, thus avoiding the need to kill them. The aims of the current study were to assess the efficacy of endoscopic examination as a monitoring tool for the severity of colitis in rats and to the efficacy of DA-9601, an extract from Artemisia asiatica which has both antioxidative and cytoprotective actions, on dextran sulfate sodium induced ulcerative colitis in rats endoscopically. Sprague-Dawley rats received 4% DSS in drinking water for 5 consecutive days. Either DA-9601 or sulfasalazine was administered twice a day for 8 days, starting 3 days before DSS administration. After the colonoscopic evaluations on days 2, 4, and 5 after DSS administration the rats were also killed for gross and histopathological evaluations. Simultaneous measurements of malondialdehyde (MDA) and myeloperoxidase (MPO) activities were performed. There was a statistically significant correlation between the scores evaluated by the gross examination and colonoscopic scores, between the colonoscopic scores and the levels of MDA or mucosal MPO activities, and between colonoscopic scores and histopathological activity index. DA-9601 showed excellent improvement in gross lesion scores, decreased MDA amounts and MPO activities compared to sulfasalazine. In conclusion, the introduction of appropriate colonoscopic examination in animal models of IBD could avoid the sacrifice of experimental animals for interim evaluation and provide the valuable information on the course and efficacy of treatment. The potential usefulness of antioxidants in treating IBD is very promising based on the colonoscopic intervention of IBD.

Oxidative damages are critical in pathogenesis of reflux esophagitis: implication of antioxidants in its treatment

BACKGROUND

The facts that the severity of reflux esophagitis cannot be accurately predicted on the basis of acid exposure and acid suppression treatment is not enough for the complete healing, suggested that other damaging factors might be involved in pathogenesis of reflux esophagitis.

AIMS

The present study was designed to evaluate the oxidative stress as the major pathogenic factor of reflux esophagitis and the importance of antioxidant in treatment of reflux esophagitis.

MATERIALS AND METHODS

Reflux esophagitis was induced by the insertion of small caliber ring (3 mm in diameter) into the duodenum 1 cm distal to the ligament of Treitz in rats.

RESULTS

DA-9601, a novel antioxidant substance, attenuated the gross esophagitis significantly compared to that treated with ranitidine, histamine-2 receptor antagonist (H2-RA), in a dose-dependent manner. Severe, hemorrhagic, and longitudinal ulcerations were developed in H2-RA pretreated group, whereas mildly scattered erosions were observed in antioxidant-pretreated group. Significantly increased amounts of malondialdehyde (MDA), increased NF-kappaB activation, and the mucosal depletion of reduced glutathione (GSH) were observed in the esophagus of reflux esophagitis. H2-RA treatment didn't affect the levels of GSH and MDA, whereas DA-9601 attenuated the decrement of the GSH levels and significantly decreased lipid peroxides in the esophagus. Antioxidants treatment showed significant reductions in the activation of NF-kappaB, inflammation-associated transcription factor, especially p50 component in accordance with significant higher levels of NF-kappaB repressor, IkappaBalpha expression.

CONCLUSION

Oxygen-derived free radicals seem to be one of the important mediators in generation of reflux esophagitis, which suggests that the combination of antioxidant and anti-secretory medications will be ideal and more beneficial in the prevention and treatment of reflux esophagitis than currently prescribed antisecretory treatment alone.

A rat model for radiation-induced proctitis

Radiation proctitis is a frequent acute complication encountered with pelvic irradiation. This study was aimed at establishing the optimal radiation dose for radiation-induced proctitis in rats. Female Wistar rats were used. The rectal specimens were examined morphologically at 5th and 10th day following 10-30 Gy irradiation in single fraction. With increasing dose, mucosal damage became worse, and there was a prominent reaction after > or =15 Gy. We selected 17.5 Gy as an optimal dose for radiation proctitis and examined specimens at day 1-14 and at week 4, 6, 8, and 12 after 17.5 Gy. The rectal mucosa revealed characteristic histological changes with time. An edema in lamina propria started as early as 1-2 days after irradiation and progressed into acute inflammation. On day 7 and 8, regeneration was observed with or without ulcer. Four weeks later, all regeneration processes have been completed with end result of either fibrosis or normal appearing mucosa. This study showed that the radiation injury of the rectum in rat develops in dose-dependent manner as it has reported in previous studies and suggested that 17.5 Gy in single fraction is the optimum dose to evaluate the protective effect of various medications for radiation proctitis in face of the clinical situation.

Erectogenic effect of the selective phosphodiesterase type 5 inhibitor, DA-8159

DA-8159, a new phosphodiesterase 5 inhibitor, was assessed for its erectogenic potential by a penile erection test in rats, the relaxation of isolated rabbit corpus cavernosum (CC), and estimation of the intracavernous pressure (ICP) in the anesthetized dog. Oral administration of DA-8159 (0.3 to 1 mg/kg) increased the number of erections in rats with increasing dosage, with the highest penile erection index at 10 mg/kg. DA-8159 induced the relaxation of phenylephrine (PHE)-induced contractions in the rabbit CC and decreased the IC50 of the nitric oxide donor sodium nitroprusside (SNP) in a dose-dependent fashion. In pentobarbital-anesthetized dogs, the intravenous administration of DA-8159 (1 approximately 300 g/kg) potentiated the increase in ICP induced by the intracavernosal SNP in a dose-related manner. These findings suggest that DA-8159 has significant therapeutic potential in the treatment of erectile dysfunction.

Studies on protective effect of DA-9601, Artemisia asiatica extract, on acetaminophen- and CCl4-induced liver damage in rats

The hepatoprotective effect of DA-9601, a quality-controlled extract of Artemisia asiatica, on liver damage induced by acetaminophen (APAP) and carbon tetrachloride (CCl4) was investigated by means of serum-biochemical, hepatic-biochemical, and histopathological examinations. Doses of DA-9601 (10, 30, or 100 mg/kg) were administered intragastrically to each rat on three consecutive days i.e. 48 h, 24 h and 2 h before a single administration of APAP (640 mg/kg, i.p.) or CCl4 (2 ml/kg, p.o.). Four h and 24 h after hepatotoxin treatment, the animals were sacrificed for evaluation of liver damage. Pretreatment of DA-9601 reduced the elevation of serum ALT, AST, LDH and histopathological changes such as centrilobular necrosis, vacuolar degeneration and inflammatory cell infiltration dose-dependently. DA-9601 also prevented APAP- and CCl4-induced hepatic glutathione (GSH) depletion and CCl4-induced increase of hepatic malondialdehyde (MDA), a parameter of lipid peroxidation, in a dose-dependent manner. These findings suggest that pretreatment with DA-9601 may reduce chemically induced liver injury by complex mechanisms which involve prevention of lipid peroxidation and preservation of hepatic GSH.