Diethylcarbamazine, antifilarial drug, inhibits microtubule polymerization and disrupts preformed microtubules.

The effect of diethylcarbamazine (DEC) on microtubules was studied by using microtubule protein prepared from porcine brain. DEC inhibited assembly of microtubules and disassembled preformed microtubules in vitro. When the reassembled or disassembled products were examined in the presence of DEC by electron microscopy, ribbon-microtubules were frequently observed. Subsequently, the effect of DEC on the cytoplasmic microtubules complex was studied. The cells used in our study were LLC-MK2. DEC inhibited proliferation of these cells, and cells grown in the presence of DEC were likely to separate from each other and became round in shape. Immunofluorescence microscopy revealed that the cells exposed to DEC were devoid of the delicate pattern of the cytoplasmic microtubule complex.