Colchicine effect on bile canalicular motility: long-term study using isolated cultured hepatocytes and time-lapse cinephotomicrography

The effect of colchicine on spontaneous in vitro contractions of bile canaliculi was assessed using time-lapse cinephotomicrography. Colchicine 2.5 microM and/or taurocholate 5 microM were added to the culture medium. The experiment was long-term, lasting for 13 h. Frame-by-frame analysis revealed that colchicine, after a lag period of 4 h, suppressed the number of contractions over the remainder of the 13-h experimental period, even in the presence of taurocholate (p less than 0.001). The number of contractions per hour decreased in both the colchicine and combined colchicine-plus-taurocholate-treated groups compared to untreated and taurocholate-treated controls. These results do not necessarily mean that colchicine has an effect on the contractile process per se, since the contractions, when they occurred, appeared normal. It is likely that the canalicular motility events are related to bile secretion. The reduction in contractions after a lag period likely indicates that secretion is impaired, and hence the need for contractions is reduced. These results support the view that for normal canalicular bile secretory function, microtubules as well as a normal microfilament system are required.