Three-dimensional morphology of C6/36 cells infected by dengue virus: a study based on digital holographic microscopy

YU Jianhai; LIU Xuling; LIU Yujing; HE Xiaoen; HUI Yuan; ZHANG Bao; ZHU Li; ZHAO Wei

doi:10.3969/j.issn.1673-4254.2017.03.04

Abstract：Objective To monitor the 3-dimensional (3D) morphological changes of C6/36 cells during dengue virus (DENV) infection using a live-cell imaging technique based on digital holographic microscopy and provide clues for better understanding the mechanisms of DENV infection.Methods C6/36 cells were seeded in 6-well plates to determine the optimal imaging density under a holographic cell imager,and the morphological changes of the cells were recorded in response to a culture temperature change from 28 ℃ to 37 ℃.C6/36 cells were infected with 4 DENV strains with different serotypes at 28 ℃ and incubated at 37 ℃ for 24 h,and the 3D holograms and relevant morphological parameters were recorded at different time points using HoloMonitor M4 holographic cell imaging and analysis system.Results The holograms of C6/36 cells inoculated at the optimal density for imaging (4 × 105 per well) showed unified 3D morphologies of the single cells with minimal dispersions in the cell area,thickness and volume (P＜0.05),which did not undergo obvious changes when the cells were incubated at 37 ℃ for 24 h (P＞0.05).The cell area and volume of the cells infected with the 4 DENV strains all increased and the cell thickness was reduced during incubation.Among the 4 strains,DENV-1 and DENV-2 caused reduced cell thickness while DENV-3 and DENV-4 increased the cell thickness,and the pattern and degree of such changes differ among the 4 strains.Conclusions Digital holographic microscopy allows monitoring of the complex morphological changes of cells during DENV infection.The 4 DENV strains with different serotypes causes characteristic cell damages during infection.