Effect of norcantharidin on human cholangiocarcinoma cells line RBE: histochemical and electron microscopic study

Abstract

Objective To observe the effect of norcantharidin on cytohistochemistry and ultrastructure of human cholangiocarcinoma RBE cells, and investigate the action mechanism of norcantharidin inducing apoptosis of RBE cells. Methods The RBE cells were cultured in vitro, followed by treatment with various concentrations of norcantharidin for 24 h.Acridine orange/ethidium bromide (AO/EB)staining was used to determine the inhibition rate and morphological changes. The ultrastructural changes were studied by scanning electron microscopy and transmission electron microscopy. Results AO/EB staining showed that with increasing dose of norcantharidin, apoptosis rate of RBE cells was increased.After treatment with 40 mg/L norcantharidin for 24 h, the apoptotic cells accounted for(83.1±15.6)%.Light microscopy and scanning electron microscopy showed typical apoptotic changes, and the formation of apoptotic bodies. The nucleus crescent- like change also could be observed by transmission electron microscopy. Conclusion Norcantharidin induces the morphological and ultrastructural changes in RBE cells, which have close relationship with apoptosis and invasion. Key words: Cholangiocarcinoma; Norcantharidin; Morphology