RPE CYTOSKELETON SENSIBILITY TO SPINDLE P OISONS

Purpose The function of RPE is well known in PVR. Pharmacological agen ts have been extensively studied both experimentally and clinically. F ew reports have detailed the interactions of antimitotic drugs on the microtubule network. The aim of this study is to visualize by indirect immunofluorescence the effects of colchicine and paclitaxel on the mi crotubule network of cultured pig RPE cells in interphase. Methods Pig s were killed at the slaughter-house, their eyes were enucleated. RPE cells were isolated and cultured. RPE cells were plated onto glass cov er-slips at a density of 2 000 000 cells/ml cultured and treated with the drugs during 4 and 24 hours at 37 degrees C at different concentra tions. Immunofluorescence reaction was developped using antitubulin an d fluoresceinated anti-mouse antibodies. The cytoskeletons were visual ized employing a Zeiss photomicroscope equiped with epiilumination, a 63 x lens and appropriate filters for fluoresceine. Results The cytopl asmic microtubules of RPE cells were disrupted in a concentration and time-dependant manner by colchicine. Between 10 and 100 nm Veveral deg rees of depolymarization of the microtubule network were observed. Pac litaxel between 1 mu m and 10 mu m was found to induce several. degree s of microtubule <<bundling>> after 4 and 24 hours of incubation. Acti n network was modified neither by colchicine and paclitaxel used in th e same conditions. Conclusions The results show that low doses of anti mitotic drugs inhibit the microtubule network formation by depolymeriz ation (colchicine) or stabilize it (paclitaxel). These actions inhibit cell division, which is one of the mechanisms implicated in PVR.