Effect of ethanol on protection of urinary bladder function by grape suspensions

To compare the protective effects of grape suspensions prepared in an aqueous vehicle with grape suspensions prepared in an 8% ethanol vehicle in rabbits subjected to partial outlet obstruction. The hypothesis was that the presence of ethanol would increase the absorption of the beneficial components of the grape suspensions and thus increase their protective ability. The use of ethanol in these studies was not to simulate wine.

A total of 48 New Zealand white rabbits were separated into eight groups of 6 rabbits each. Groups 1 and 3 were pretreated by oral gavage for 3 weeks with grape suspensions in water; groups 2 and 4 were treated with vehicle. Groups 5 and 7 were treated with the grape suspensions in 8% ethanol, and groups 6 and 8 were treated with ethanol vehicle. Groups 1, 2, 5, and 6 underwent sham operations, and groups 3, 4, 7, and 8 underwent partial outlet obstruction. Three weeks after surgery, the rabbits were evaluated.

The bladder weight had significantly increased in all obstructed groups. The contractile responses to field stimulation and carbachol were reduced in all obstructed groups, although the responses in both grape-treated groups were greater than both vehicle-treated groups. The contractile responses to potassium chloride were significantly reduced by partial outlet obstruction in both obstructed groups similarly.

Both grape suspensions provided protection against obstructive-induced bladder dysfunction. The ethanol preparation of the grape suspension was not better than the aqueous preparation.