Saireito (TJ-114), a Japanese traditional herbal medicine, reduces 5-fluorouracil-induced intestinal mucositis in mice by inhibiting cytokine-mediated apoptosis in intestinal crypt cells.

Clinical chemotherapy frequently causes intestinal mucositis as a side effect, which is accompanied by severe diarrhea. We recently showed that the cytokine-mediated apoptotic pathway might be important for the development of intestinal mucositis induced by 5-fluorouracil (5-FU). Saireito, the traditional Japanese herbal (Kampo) medicine, is widely used to treat diarrhea and various inflammatory diseases in Japan. In the present study, we investigated the effect of saireito on 5-FU-induced intestinal mucositis in mice, especially in relation to apoptosis in the intestinal crypt. Male C57BL/6 mice were given 5-FU (50 mg/kg), i.p. once daily for 6 days. Intestinal mucositis was evaluated histochemically. Saireito (100-1000 mg/kg) was administered p.o. twice daily for 6 days. Repeated 5-FU treatment caused severe intestinal mucositis including morphological damage, which was accompanied by body weight loss and diarrhea. Daily administration of saireito reduced the severity of intestinal mucositis in a dose-dependent manner. Body weight loss and diarrhea during 5-FU treatment were also significantly attenuated by saireito administration. The number of apoptotic and caspase-3-activated cells in the intestinal crypt was increased, and was accompanied by up-regulated tumor necrosis factor (TNF)-α and interleukin (IL)-1ß mRNA within 24 h of the first 5-FU injection. However, all of these measures were significantly lower after saireito administration. These results suggest that saireito attenuates 5-FU-induced intestinal mucositis. This action may come from the reduction of apoptosis in the intestinal crypt via suppression of the up-regulation of inflammatory cytokines. Therefore, saireito may be clinically useful for the prevention of intestinal mucositis during cancer chemotherapy.

Mucosal protective agents prevent exacerbation of NSAID-induced small intestinal lesions caused by antisecretory drugs in rats.

Antisecretory drugs such as histamine H2-receptor antagonists and proton pump inhibitors are commonly used for the treatment of upper gastrointestinal mucosal lesions induced by nonsteroidal anti-inflammatory drugs (NSAIDs). However, it has recently been reported that these drugs exacerbate NSAID-induced small intestinal lesions in rats. Unfortunately, there are few effective agents for the treatment of this complication. We examined the effects of mucosal protective agents (MPAs) (misoprostol, irsogladine, and rebamipide) and mucin of porcine stomach on diclofenac-induced intestinal lesions and the exacerbation of the lesions by ranitidine or omeprazole. The effects of the drugs on intestinal motility and mucus distribution/content were also examined. Male Wistar rats (180-220 g) were used. Each drug was administered orally under fed conditions. Diclofenac (1-10 mg/kg) produced multiple lesions in the small intestine dose-dependently. Both ranitidine (30 mg/kg) and omeprazole (100 mg/kg) significantly increased the intestinal lesions induced by low doses (3 and 6 mg/kg) of diclofenac. Misoprostol (0.03-0.3 mg/kg), irsogladine (3-30 mg/kg), and rebamipide (30-300 mg/kg), as well as mucin (30-300 mg/kg) inhibited the formation of intestinal lesions caused by a high dose (10 mg/kg) of diclofenac alone and prevented the exacerbation of diclofenac-induced lesions by antisecretory drugs. Diclofenac (10 mg/kg) markedly increased the intestinal motility and decreased the mucosal mucus, and the decrease of mucus was significantly inhibited by the MPAs. These results indicate the usefulness of the MPAs for the treatment of intestinal lesions induced by NSAIDs alone or by coadministration with antisecretory drugs, and suggest that mucus plays an important role in the protection of intestinal mucosa by the MPAs.

Exacerbation of nonsteroidal anti-inflammatory drug-induced small intestinal lesions by antisecretory drugs in rats: the role of intestinal motility.

Antisecretory drugs such as histamine H2-receptor antagonists (H2-RAs) and proton pump inhibitors (PPIs) are commonly used for the treatment of gastric and duodenal ulcers induced by nonsteroidal anti-inflammatory drugs (NSAIDs). However, the effects of these drugs on NSAID-induced small intestinal ulcers are not fully understood. The effects of H2-RAs and PPIs on NSAID-induced gastrointestinal lesions and small intestinal motility were examined in rats. Male Wistar rats (180-220 g) were used. Indomethacin (10 mg/kg) was administered orally in fasted or fed rats, and gastrointestinal lesions were examined 24 h after indomethacin administration. Intestinal motility was measured by using a balloon method under urethane anesthesia. Indomethacin produced multiple lesions in the gastric corpus in fasted rats and in the small intestine in fed rats: 1) H2-RAs (cimetidine, ranitidine, and famotidine) and PPIs (omeprazole, lansoprazole, and rabeprazole) markedly inhibited the formation of gastric lesions. 2) The drugs, except for lansoprazole, increased intestinal lesions. 3) H2-RAs augmented the increase in intestinal motility caused by indomethacin, and the effects of H2-RAs on motility and intestinal lesions were markedly inhibited by atropine. 4) Lansoprazole inhibited the formation of intestinal lesions, and the effect was prevented by both pharmacological ablation of capsaicin-sensitive sensory neurons and pretreatment with N-nitro-l-arginine methyl ester, a selective inhibitor of nitric-oxide synthesis. The results suggest that: 1) inhibition of acid secretion by antisecretory drugs may exacerbate NSAID-induced intestinal lesions, 2) H2-RAs further aggravate lesions by increasing intestinal motility via the activation of cholinergic pathways, and 3) lansoprazole protects the intestinal mucosa against NSAID-related ulcerative stimuli.

[Prophylactic effect of glutamate on gastrointestinal damage].

Glutamate is known as the umami substance in the diet and umami taste has been traditionally preferred in East Asian countries. Recent our and others' studies showed that glutamate has potential to protect the gastrointestinal mucosa against noxious agents. In contrast, Helicobacter pylori infection and non-steroidal anti-inflammatory drugs (NSAIDs) are recognized as the two major causes of gastrointestinal diseases characterized by gastritis or gastrointestinal ulcers. We examined whether dietary supplementation of glutamate prevents the Helicobacter pylori infection- and NSAIDs-induced gastrointestinal damages in animal models. In this paper, we first review how these noxious agents develop gastrointestinal damages, and secondly discuss the possible candidates of protective factors as well as the mechanisms how glutamate prevents these gastrointestinal damages. We propose that our daily intake of glutamate has important roles in protecting the gastrointestinal mucosa against Helicobacter pylori and NSAIDs and possibly contributes to the maintenance of our healthy lives.

Aggravation of cold-restraint stress-induced gastric lesions in adjuvant arthritic rats: pathogenic role of inducible and endothelial nitric oxide.

It was reported previously that non-steroidal anti-inflammatory drugs (NSAID)-induced gastric damage was markedly aggravated in rats during arthritis, and this response was mediated by the overproduction of nitric oxide (NO) derived from endothelial NO synthase (eNOS) in addition to inducible NO synthase (iNOS). The present study examined the gastric ulcerogenic response to cold-restraint stress in adjuvant arthritic rats, particularly in relation to NO/NOS isozymes. Exposure of normal rats to cold-restraint stress (13 degrees C) produced slight gastric damage 3 h later, but the ulcerogenic response was markedly aggravated in arthritic rats. Pretreatment with N(G)-nitro-L-arginine methyl ester (L-NAME) (a nonselective inhibitor of NOS) slightly increased the cold-restraint stress-induced gastric lesions in normal rats, but dose-dependently prevented the aggravation of these lesions in arthritic rats. The increased ulcerogenic response in arthritic rats was significantly suppressed by 1400 W (a selective inhibitor of iNOS) and L-iminoethyl ornithine (L-NIO) (a selective inhibitor of eNOS), but not by N(G)-propyl-L-arginine (L-NPA) (a selective inhibitor of nNOS), and almost totally abolished by the co-administration of 1400 W and L-NIO. The mucosal expression levels of eNOS and iNOS but not nNOS mRNAs were enhanced in arthritic rats compared with normal rats. The aggravation of stress-induced gastric lesions in arthritic rats was also significantly suppressed by pretreatment with glutathione. These results suggest that the gastric ulcerogenic response to cold-restraint stress is enhanced in arthritic rats, similar to that induced by NSAIDs, and this phenomenon may be causally associated with the upregulation of eNOS/NO in addition to iNOS/NO.

Impairment by 5-fluorouracil of the healing of gastric lesions in rats: effect of lafutidine, a histamine H2 receptor antagonist, mediated by capsaicin-sensitive afferent neurons.

We investigated the influence of 5-fluorouracil (5-FU), an anti-tumor agent, on the healing of gastric lesions generated by 0.6 M HCl in rats and the effect of lafutidine, a histamine H(2) receptor antagonist, on the impaired healing. Animals fasted for 18 h were given 1 ml of 0.6 M HCl p.o., fed normally from 1 h later, and killed 1-96 h thereafter. 5-FU was given i.v. twice, 1 h and 24 h after the HCl. The gastric lesions healed spontaneously within 96 h. Although it decreased acid secretion, 5-FU markedly delayed the healing. Lafutidine, but not cimetidine, given p.o. immediately after each dosing of 5-FU significantly reversed the delay in healing by 5-FU, and this effect was attenuated by the chemical ablation of capsaicin-sensitive afferent neurons. Capsaicin also significantly reversed the delay in healing. The mucosal application of 50 mM HCl did not affect gastric mucosal blood flow (GMBF) in the normal stomach, but significantly increased it in the stomach damaged by 0.6 M HCl. The increases in GMBF were attenuated by 5-FU; however, the co-administration of lafutidine significantly restored the response. In addition, 5-FU inhibited both cell proliferation and migration in rat gastric epithelial cells (RGM1) in vitro. These results suggest that 5-FU delayed the healing of gastric lesions generated by 0.6 M HCl, probably through the inhibition of cell migration and proliferation, as well as the impairment of GMBF, and lafutidine reversed the delay in healing, mainly through the amelioration of the GMBF response mediated by capsaicin-sensitive afferent neurons.

Absorption of interferon alpha from patches in rats.

Interferon alpha (IFN-alpha), patch preparations composed of three layers, water-insoluble backing layer, drug containing layer with absorption enhancer and surface layer containing pH-dependent polymer were prepared. As absorption enhancer, three surfactants, Gelucire44/14 (Lauroyl macrogol-32 glycerides), Labrasol (Caprylocaproyl macrogol-8 glycerides) and HCO-60 (polyoxyethylated hydrogenerated castor oil) were used in preparing IFN-alpha patch preparations. The intestinal absorption of IFN-alpha was studied after the administration of test patch preparations into the rat jejunum, 50,000 IU/kg. The serum IFN-alpha levels were measured by an ELISA method and both C(max) and AUC were determined as the index of absorption of IFN-alpha. Gelucire44/14 preparation including Pharmasol for the stable solidification showed the higher C(max), 7.66 +/- 0.82 IU/ml, and AUC, 12.85 +/- 1.49 IU h/ml, than Labrasol (6.51 +/- 0.89 and 8.30 +/- 1.34 IU h/ml) and HCO-60 (6.02 +/- 1.14, 7.53 +/- 1.84 IU h/ml) preparations, respectively. By comparing to the AUC obtained after s.c. injection of the same dose of IFN-alpha to rats, bioavailability (BA) was estimated to be 7.8% in Gelucire44/14 preparation. In vitro release study showed that the T50%s, the time when half of the formulated IFN-alpha is released from the patches, were 3.4 +/- 0.1 min for HCO-60, 7.8 +/- 0.1 min for Gelucire44/14 and 11.4 +/- 0.1 min for Labrasol preparations. To study the effect of absorption site, Gelucire44/14 preparation was administered into the rat duodenum and ileum. However, there were not significant differences on AUC among the three absorption sites. By reducing the IFN-alpha dose from 50,000 to 25,000 IU/kg, the serum IFN-alpha levels vs time profile showed a tendency of dose-dependency. When the histological examination of small intestinal mucosa was carried out in this study, the small intestinal mucosa after the Gelucire44/14 patches administered and before it was administered, could not recognize impaired. From these results, the usefulness of oral patch system for the oral delivery of IFN-alpha has been proved in rats.

[An overview of acetic acid ulcer models and their utility for drug screening].

Since Takagi et al. reported an experimental chronic gastric ulcer model [acetic acid ulcers induced by submucosal injection of acetic acid (Type 1)], we further modified the methodology and subsequently devised three more models. The second model involves inducing ulcers by serosal application of an acetic acid solution (Type 2) and the third model achieves ulcer induction by intragastric application of an acetic acid solution (Type 3). The forth model was modification of the third model by giving the acetic acid solution and the same volume of air to make one ulcer in the stomach (Type 4). In general, animals accepted the procedures without problems and no undesirable effects were noticed. More importantly, this experimental animal model allows production of ulcers that highly resemble human ulcers in terms of both pathology and healing. Indeed, relapse is even endoscopically observed for 360 days after ulceration. The ulcers produced not only respond well to various anti-ulcer medications, such as antisecretory and mucosal protective drugs and growth factors, but also demonstrate appropriate responses to ulcerogenic agents such as NSAIDs. In addition, we have recently demonstrated that H. pylori infection resulted in delayed ulcer healing and recurrence of healed acetic acid ulcers induced in Mongolian gerbils. The present article gives a brief summary of the ulcer history before establishment of acetic acid ulcers and characteristic features of acetic acid ulcer, including both their merits and shortcomings.