Acanthamoeba migration in an electric field

Abstract

PURPOSE. We investigated the in vitro response of Acanthamoeba trophozoites to electric fields (EFs). METHODS. Acanthamoeba castellanii were exposed to varying strengths of an EF. During EF exposure, cell migration was monitored using an inverted microscope equipped with a CCD camera and the SimplePCI 5.3 imaging system to capture time-lapse images. The migration of A. castellanii trophozoites was analyzed and quantified with ImageJ software. For analysis of cell migration in a three-dimensional culture system, Acanthamoeba trophozoites were cultured in agar, exposed to an EF, digitally video recorded, and analyzed at various Z focal planes. RESULTS. Acanthamoeba trophozoites move at random in the absence of an EF, but move directionally in response to an EF. Directedness in the absence of an EF is 0.08±0.01, while in 1200 mV/mm EF, directedness is significantly higher at -0.65±0.01 (P < 0.001). We find that the trophozoite migration response is voltage-dependent, with higher directionality with higher voltage application. Acanthamoeba move directionally in a three-dimensional (3D) agar system as well when exposed to an EF. CONCLUSIONS. Acanthamoeba trophozoites move directionally in response to an EF in a twodimensional and 3D culture system. Acanthamoeba trophozoite migration is also voltagedependent, with increased directionality with increasing voltage. This may provide new treatment modalities for Acanthamoeba keratitis. © 2013 The Association for Research in Vision and Ophthalmology, Inc.