Ra. Hirst et al., Effect of pneumolysin on rat brain ciliary function: Comparison of brain slices with cultured ependymal cells, PEDIAT RES, 47(3), 2000, pp. 381-384
This study compares two models for examining ependymal ciliary function: ra
t brain slices cut from the fourth ventricle and primary ependymal cells in
culture. The cilia from both preparations were very reproducible; each pre
paration had cilia beating at a constant frequency of between 38 and 44 Hz.
With the brain slices, ciliary stasis occurred after 5 d in culture. Howev
er, ependymal cells had fully functional cilia for up to 48 d in culture. T
he pneumococcal toxin, pneumolysin, caused a dose-dependent inhibition of c
ilia beat frequency within 15 min in both models. There were no significant
differences in the mean log 50% inhibitory concentration (pIC(50)) slice =
0.65 +/- 0.05, equivalent to 4.4 hemolytic units (HU)/mL; cells = 0.57 +/-
0.14, equivalent to 3.7 HU/mL. There were also no significant differences
in the mean Hill slope factors for the curves (slice = 1.4 +/- 0.05; cells
= 1.6 +/- 0.4). These data demonstrate that both models can be used to exam
ine the acute (15-min) effects of pneumolysin on cilia beat frequency. The
main advantage of the primary ependymal culture model is that considerably
more cultured ependymal cells (similar to 70%) are available, compared with
the number of ependymal cells on the brain slices (similar to 2%), thus re
ducing the number of animals used. A pure ependymal culture was not achieve
d (similar to 30% of the cells were not ciliated). The increased survival t
ime of the ependymal cells compared with the brain slices make cultured epe
ndymal cells more useful for examining long-term ciliary function, whereas
brain slices may be more useful for examining the interactions between epen
dymal and other nearby cells.