The Antiemetic Effect of Xiao-Ban-Xia-Tang Formula is Associated With Regulating CaM/CaMKII/ERK1/2 Signaling Pathway in Cisplatin and 1-phenylbiguanide Hydrochloride Induced Rat Pica Models

Abstract Background: Xiao-Ban-Xia-Tang (XBXT) formula is a traditional Chinese herbal formula for treating emesis. Chemotherapy-induced nausea and vomiting (CINV) are serious side effects of chemotherapy, which was closely related to the activation of 5-hydroxytryptamine 3 receptor (5-HT3R). In this paper, the effect of XBXT on cisplatin- and 1-phenylbiguanide hydrochloride (1-PBG, a selective 5-HT3R agonist)- induced pica behavior in male Wistar rats and inhibition of calmodulin/calmodulin-dependent protein kinase II/extracellular signal-regulated kinase 1/2 (CaM/CaMKII/ERK1/2) signaling pathway were investigated. Methods: XBXT (1.6 g/kg, twice daily) was orally administered from day 1 after intraperitoneal injection of cisplatin (6 mg/kg) and 1-PBG (25 mg/kg) to day 3. Pica behavior (consumption of kaolin, a type of clay) was recorded every 24 h. The expression and co-localization of CaM and 5-HT3R in small intestine and brain were detected by immunofluorescence. The expression of CaMKII, pCaMKII, ERK1/2, and pERK1/2 proteins were detected by Western blot. Results: XBXT treatment significantly decreased kaolin ingestion (pica) of rats after treatment of cisplatin and 1-PBG during both 0 - 24 h (respectively, from 1.57 g to 0.87 g; from 1.04 g to 0.11 g) and 0 - 72 h (respectively, from 2.98 g to 1.85 g; from 2.29 g to 0.35 g) periods. The fluorescence expression of CaM and 5-HT3R and expression of CaMKII, pCaMKII, ERK1/2 and pERK1/2 in the small intestine and brain of cisplatin- and 1-PBG-treated rats were remarkably suppressed by XBXT.Conclusions: The present study implies that inhibiting CaM/CaMKII/ERK1/2 signaling is an underlying mechanism of XBXT for treating CINV. These insights provide an experimental basis of XBXT for the clinical treatment of CINV.