Interactive image analysis programs for quantifying injury-induced axonal beading and microtubule disruption.

Focal axonal beading and focal disruption of microtubule structure are characteristic to traumatic axonal injury. We have recently reproduced these morphological and structural changes in our in vitro model system [D. Kilinc, G. Gallo, K.A. Barbee, Mechanically induced membrane poration causes axonal beading and localized cytoskeletal damage, Exp. Neurol. 212 (2008) 422-430]. In order to measure bead formation objectively, an observer-independent quantification of beading was necessary. In addition, a quantitative measure for the extent of co-localization of axonal beads and microtubule disruptions was required to establish a causal relationship between focal cytoskeletal damage and bead formation. In this paper we describe Matlab-based, interactive image analysis programs for axonal beading quantification and co-localization analysis. Injury-induced increases in the axonal beading could be successfully detected using the bead analysis program.