Combined trypan blue and glyoxylic acid-induced catecholamine fluorescence in the female rat urinary bladder after distension.

The effect of short-term urinary bladder distension on bladder perfusion and adrenergic innervation was studied in Sprague-Dawley rats. Distension was induced for three hours by forced diuresis and balloon obstruction. A 2% solution of trypan blue was injected into the tail vein 12, 24, 36 and 48 hours after distension and the animals were killed 5-10 min after the injection. Whole thick biopsies were taken from the dome, anterior body and base. A combination of trypan blue and catecholamine fluorescence (GIF method) was used to correlate the distension induced changes in blood vessel perfusion and permeability with changes in adrenergic innervation. Both ischaemic damage and adrenergic hypoinnervation were observed after distension. Later marked extravasation of trypan blue was observed in the whole bladder after 12 hours and after 24 hours distension the dome was almost necrotic in appearance and highly ischaemic. After 36 hours a few exploded small, intensely fluorescent cells (SIF cells) were found to be scattered along the blood vessels, and degranulated mast cells had invaded the anterior body and dome. The adrenergic hypoinnervation reached its maximum 48 hours after distension. The hypoinnervation and possibly also the damage to SIF cells, would seem to be related to ischaemia during distension, probably attributable in turn to overstretching of the organ and its blood vessels. This may provide an explanation for the prolonged micturition problems found after bladder overdistension.