The utility of noninvasive (13)C-acetate breath test using a new solid test meal to measure gastric emptying in mice

Hangekobokuto, a traditional Japanese herbal medicine, ameliorates postoperative ileus through its anti-inflammatory action

Background/Aims: Gastroprokinetic agents are used for patients with postoperative ileus (POI), and the Japanese traditional herbal medicine daikenchuto (DKT) is one such agent used in the clinical setting. POI is caused by inflammation. DKT and rikkunshito have anti-inflammatory abilities in addition to their gastroprokinetic effects. The efficacy of Kampo formulations, including hangekobokuto (HKT), in patients with POI has been reported recently. Several authors have described the efficacy of honokiol, the primary component of Magnoliae Cortex, in HKT in mouse models of POI. We therefore analyzed the effect of HKT on POI model mice to determine the similarities in the mechanism of action between HKT and DKT.

Methods: HKT was administered orally to each mouse before and after intestinal manipulation was performed on the distal ileum. The gastrointestinal transit in vivo, leukocyte infiltration, and levels of inflammatory mediators, such as cytokines and chemokines, were analyzed.

Results: HKT significantly inhibited the infiltration of neutrophils and macrophages and led to the recovery of delayed intestinal transit. In addition, it significantly decreased inducible nitric oxide synthase (iNOS) as well as honokiol levels, suggesting anti-inflammatory activity. However, it did not inhibit the increase in levels of interleukin (IL)-1beta and IL-6, which are related to iNOS induction. In contrast, HKT increased levels of nerve growth factor (NGF) and suppressed those of nuclear factor-κB (NFκB), which are related to iNOS induction, suggesting the possibility of a neuronal anti-inflammatory mechanism.

Conclusions: HKT exerted a POI-relieving effect similar to DKT in a murine POI model, and findings suggest that it may exert its anti-inflammatory activity through NGF.

Utility of animal gastrointestinal motility and transit models in functional gastrointestinal disorders

Alteration in the gastrointestinal (GI) motility and transit comprises an important component of the functional gastrointestinal disorders (FGID). Available animal GI motility and transit models are to study symptoms (delayed gastric emptying, constipation, diarrhea) rather than biological markers to develop an effective treatment that targets the underlying mechanism of altered GI motility in patients. Animal data generated from commonly used methods in human like scintigraphy, breath test and wireless motility capsule may directly translate to the clinic. However, species differences in the control mechanism or pharmacological responses of GI motility may compromise the predictive and translational value of the preclinical data to human. In this review we aim to provide a summary on animal models used to mimic GI motility alteration in FGID, and the impact of the species differences in the physiological and pharmacological responses on the translation of animal GI motility and transit data to human.

Daikenchuto, a traditional Japanese herbal medicine, ameliorates postoperative ileus by anti-inflammatory action through nicotinic acetylcholine receptors

BACKGROUND

Daikenchuto (DKT), a gastrointestinal prokinetic Japanese herbal medicine, is prescribed for patients with postoperative ileus (POI) and adhesive bowel obstruction following abdominal surgery. Several mechanisms for the amelioration of POI by DKT have been suggested; however, it has remained unclear whether DKT shows anti-inflammatory effects in POI. In the present study, we investigated the effects of DKT in a mouse POI model and attempted to clarify the detailed mechanisms of action.

METHOD

Intestinal manipulation (IM) was applied to the distal ileum of mice. DKT was administered orally to the animals 4 times before and after IM. Gastrointestinal transit in vivo, leukocyte infiltration, cytokine mRNA expression and gastrointestinal motility were analyzed. We also investigated the effects of the α7nAChR antagonist methyllycaconitine citrate (MLA) on the DKT-mediated ameliorative action against POI, and we studied the effects of DKT on inflammatory activity in α7nAChR knockout mice.

RESULTS

DKT treatment led to recovery of the delayed intestinal transit induced by IM. DKT significantly inhibited the infiltration of neutrophils and CD68-positive macrophages, and inhibited mRNA expressions of TNF-α and MCP-1. MLA significantly reduced the anti-inflammatory action of DKT, and the amelioration of macrophage infiltration by DKT was partially suppressed in α7nAChR knockout mice.

CONCLUSIONS

In conclusion, in addition to the gastrointestinal prokinetic action, DKT serves as a novel therapeutic agent for POI characterized by its anti-inflammatory potency. The DKT-induced anti-inflammatory activity may be partly mediated by activation of α7nAChR.

Effect of atropine sulfate on gastric emptying and gastrocecal transit time evaluated by using the [1-(13)C]acetic acid and lactose-[(13)C]ureide breath test in conscious rats

Breath tests have been used to investigate many physiological functions. Recently, we have developed a breath test system by using a non-invasive technique in conscious rats. In this study, we investigated the effect of atropine sulfate on the gastric emptying and gastrocecal transit time using [1-(13)C]acetic acid and lactose-[(13)C]ureide, respectively. Gastric emptying was significantly delayed by atropine sulfate in a dose-dependent manner (0.03-0.3 mg kg(-1)), but the effects of 0.1 and 0.3 mg kg(-1) were almost equal. C(max) and T(max) values were also significantly and dose-dependently decreased and delayed, respectively. However, AUC(120 min) values were not significantly different for the three doses of atropine sulfate. This suggests that although atropine sulfate slows the emptying of the gastric content, it is excreted eventually to the same content as the control. The gastrocecal transit time was significantly delayed by atropine sulfate at a dose of 1 mg kg(-1), but not at a dose of 0.1 mg kg(-1). These findings demonstrate that the breath tests can evaluate the effect of atropine sulfate on the gastric emptying and gastrocecal transit time. The effective dose of atropine sulfate may be different for gastric emptying and gastrocecal transit time.