Anorexia is common in patients with cancer, mostly as a side effect of chemotherapy. The effect of electro-acupuncture (EA) on ameliorating cancer-related symptoms have been studied in animal models and in clinical trials. The aim of this study was to determine optimal conditions for the application of EA to alleviate anorexia, followed by the study of molecular mechanisms affecting its therapeutics. Anorexia was induced in male Wistar rats by injecting cisplatin, which was then followed by EA treatment at CV12, the acupuncture point located in the center of the abdominal midline. Body weight and food intake were measured daily throughout the duration of the study. The levels of monoamine neurotransmitters in the plasma were quantitatively analyzed by HPLC-ECD. Gastrointestinal hormone concentrations were elucidated with ELISA kits. RT-qPCR was performed to evaluate the mRNA expression of ghrelin (GHRL), neuropeptide Y (NPY), and pro-opiomelanocortin. The expression of c-Fos in the nucleus tractus solitarii was detected using western blotting analysis. The optimal conditions of EA to alleviate anorexia in rats was determined to be 1 unit for intensity and 10 Hz for frequency. EA treatment at CV12 reduced the levels of plasma monoamine neurotransmitters 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, dopamine, and norepinephrine; as well as stimulated the expression of GHRL and NPY to alleviate cisplatin-induced anorexia in rats. EA stimulation at CV12 could be used to treat cisplatin-induced anorexia in rats.
Keywords: 5-hydroxytryptamine; anorexia; cancer; cisplatin; electro-acupuncture; ghrelin; neuropeptide Y; pro-opiomelanocortin.