Fig. 5

In vitro effects of NA and complement on ependymal cell viability. Pure ependymal cells were isolated from adult rats and placed in culture in the presence of NA and/or complement. Rat serum was used as a source of complement. a, b The viability of cells was monitored by the exclusion of trypan blue stain; the living ependymal cells excluded the dye (a) while the dead cells stained blue (b). Arrows point to the cilia. c The graph shows the percentage of live cells at different time points relative to living cells at time zero. The data are mean ± SEM of three independent experiments. In the presence of NA and serum, there was a steep decline of the viability as soon as 10 min after the start of the exposure, which continued dropping up to 40 % survival after 30 min. A milder decline in viability was also observed in cells treated with NA alone with no serum. The involvement of the complement in facilitating NA-induced cell death was tested by using a complement blocking antibody (C5-inh), which completely reversed the survival rate to the values obtained with NA alone. CM culture medium, NA neuraminidase, C5-inh C5 inhibitor; *P < 0.05; **P < 0.01 compared to the control CM