Prevention of cisplatin-induced nausea and vomiting by seabuckthorn (Hippophae rhamnoides L.) seed oil: Insights at the level of orexin-A in rats

Nausea and vomiting are perennial problems in cancer patients undergoing chemotherapy. Orexin-A (OXA) has been shown to regulate feeding and gastric motility. Seabuckthorn (Hippophae rhamnoides L.) seed oil (SSO) has been proved to promote digestion and bowel movements. We investigated whether SSO alleviated cisplatin-induced vomiting and its possible mechanism involved in OXA. Rats were randomly divided into normal control group (NCG), cisplatin group (CG), SSO low-dose group (SLG), SSO middle-dose group (SMG) SSO high-dose group (SHG), and ondansetron group (OG). Rats were pretreated respectively with SSO (0.850, 1.675, and 3.350 g/kg·BW) and ondansetron (2 mg/kg·BW) in SLG, SMG, SHG, and OG for 6 days, and the same volume of saline in NCG and CG groups. On the 6th day, cisplatin (6 mg/kg, IP) was administered in all groups except NCG. The cumulative food and kaolin intake, gastric emptying, plasma OXA level, OX1R mRNA and protein expression in the hypothalamus and brainstem, and OXA expression in the lateral hypothalamic area (LHA) were observed, and the HPLC method was used to analyze the composition of SSO.   Kaolin intake in cisplatin-induced vomiting rats was significantly reduced (p <0.05) and gastric emptying delayed by cisplatin was improved (p <0.05-0.01) by pretreatment with SSO. Plasma OXA concentration, OX1R expression in the hypothalamus and brainstem increased significantly (p <0.05–0.01). Furthermore, OXA expression in LHA also increased significantly (p <0.05). SSO prevents cisplatin-induced vomiting in rats, which is possibly involved in increasing peripheral and central OXA and the expression of OX1R in the hypothalamus and brainstem.