[Endogenous metabolites involving effects of moxibustion on injured gastric mucosal tissue in rats with stomach heat or cold syndrome based on nuclear magnetic resonance spectroscopy].

Objective: To investigate the profile of metabolites of gastric mucosa involving the effectiveness of moxibustion in the treatment of syndromes of stomach heat (SH) and stomach cold (SC) by H-nuclear magnetic resonance (H-NMR) spectroscopy in rats, so as to reveal its mechanisms underlying improvement of gastric disorders.

Methods: Male SD rats were randomly divided into control, SH-model, SC-model, SH-moxibustion and SC-moxibustion groups (＝6 rats/group). The SH-model and SC-model were established by gavage of pepper liquid plus ethanol, and ice water plus NaOH, respectively. Moxibustion was applied to bilateral "Zusanli" (ST36) and "Liangmen"(ST21) for 20 min, once daily for 7days. Histopathological changes of the gastric tissue were observed by H．E. staining. Differential metabolites in the gastric mucosal tissue were detected and the relevant metabolic pathways analyzed by using H-NMR, pattern recognition method，and online MetPA (http: //www.metaboanalyst.ca).

Results: Compared with the control group, the body mass was decreased significantly from the 4 to 14 day after modeling (<0.05，<0.01). After the treatment, the body mass was obviously increased from the 10 day on in both SH-EA and SC-EA groups relevant to the SH and SC model group, respectively (<0.05，<0.01). H．E. staining showed severe damage of the columnar epithelial structure of the gastric mucosa and inflammatory cell infiltration in the SH group, and inflammatory cell infiltration in the SC model group, which were relatively milder in both moxibustion groups. H-NMR analysis displayed a total of 16 potential biomarkers in the injured gastric mucosa of SH syndrome and 14 biomarkers for the SC syndrome after mode-ling, and 13 metabolites related to SH moxibustion and 8 metabolites related to SC moxibustion after moxibustion interventions, respectively. After moxibustion, among the 13 differential metabolites of the SH syndrome, the effectively up-regulated candidates were isoleucine, creatinine, choline and lactate (<0.05), and the down-regulated ones were choline phosphate, glycine, alanine, urine pyrimidine, tyrosine, phenylalanine, hypoxanthine, adenosine and nicotinamide (<0.05). Among the 8 metabolites related to the SC syndrome, creatinine, ethanolamine, choline, adenosine and nicotinamide were markedly increased (<0.05), and glycine, creatine phosphate and tyrosine remarkably decreased in their levels after moxibustion (<0.05). MetPA showed that moxibustion could regulate 10 metabolic pathways for SH syndrome and 7 metabolic pathways for SC syndrome. Metabolites and metabolic pathways are mainly involved in functions of amino acid metabolism, energy metabolism and inflammatory response.

Conclusion: The idea of "moxibustion could be used for heat syndrome" has metabolic substance basis, and its efficacy in repairing the injured gastric mucosa involves regulation of amino acid metabolism, energy balance and inflammation response, and moxibustion for SH and SC syndromes has both generality and specificity in regulating metabolic activities.