Cardiotoxicity induced by xanthatin via activating apoptosis and ERS pathways in zebrafish

Xanthatin, a sesquiterpene lactone compound, isolated from Chinese herb, Xanthium strumarium L, has various activities, including anti-inflammatory, anti-tumor, anti-ulcer effects. However, it has been less studied in terms of its toxicity, especially the potential toxicity on heart. This study is mainly aimed to assess the cardiotoxicity of xanthatin in vivo using zebrafish larva and in vitro using cardiomyocytes H9C2. The cardiotoxicity in zebrafish was assessed by the pericardial edema, blood flow dynamics, SV-BA distance, and sub-intestinal vein. The apoptosis was determined by AO staining, the blood red cell reduction and distribution was detected by O-dianisidine staining, histopathological evaluations were detected by HE staining. The anti-proliferative and pro-apoptotic activities in H9C2 cells were assessed by EdU staining and Hoechst 33342/PI double staining. The in vivo results showed that xanthatin caused cardiac malformations and dysfunctions, including decreased heart rate, reduced red blood cell count, hemodynamics, stroke volume, increased SV-BA distance and sub-intestinal vein congestion. Furthermore, apoptosis occurred in the heart of the zebrafish after xanthatin exposure. Additionally, cat, Mn-sod, chop, perk, and hspa5 related to oxidative stress and ERS also changed by xanthatin. Apoptotic genes caspase3 and caspase9 were also increased. Moreover, the in vitro results showed that xanthatin had proapoptotic and antiproliferative effects. To sum up, these results suggest that xanthatin has cardiotoxicity and the oxidative stress, ERS and apoptosis pathways are involved in the cardiotoxicity induced by xanthatin. This finding will be helpful for the better understanding of the potential cardiotoxicity of xanthatin and the underlying mechanism.