The effect of ethanol and acetaldehyde on brain ependymal and respiratory ciliary beat frequency

BACKGROUND: Ethanol has been shown to stimulate the beat frequency of respiratory cilia at concentrations encountered during social drinking, while one of its metabolites, acetaldehyde, has been shown to cause a marked decrease in ciliary beat frequency. The aim of this study was to determine whether short-term exposure to ethanol stimulated ependymal cilia and whether exposure to acetaldehyde had a toxic effect on ependymal and respiratory cilia. METHODS: Using ex vivo rat ependymal brain slice and human nasal brush biopsy models, we investigated the effect of exposure of cilia to various concentrations of ethanol and acetaldehyde at either 37°C or 24°C. Ciliary beat frequency was measured using digital high-speed video analysis. RESULTS: Exposure of ependymal and respiratory cilia to control, 0.1%, 0.5% and 1% ethanol solutions resulted in a maximal increase of 15% in the ciliary beat frequency from baseline values, compared with the control of 6%. A one-way analysis of variance comparing the mean slopes for the three concentrations of ethanol and control showed no significant differences between the groups (P >0.05). Exposure of ependymal and respiratory cilia to 100 and 250 μM acetaldehyde solutions resulted in a maximal increase of 15% in the ciliary beat frequency from baseline, compared with the control of 12%. A one-way analysis of variance performed to compare the mean slopes in these groups showed no significant differences (P >0.05). CONCLUSIONS: Short-term exposure of brain ependymal and respiratory cilia to the concentrations of ethanol likely to be encountered during episodes of heavy drinking and to acetaldehyde at concentrations well above those encountered by man did not have a significant effect on ciliary beat frequency.