Aspirin treatment improves bladder function after outlet obstruction in rabbits

Effects of chronic treatment with cilostazol, a phosphodiesterase 3 inhibitor, on female rat bladder in a partial bladder outlet obstruction model

OBJECTIVE

To investigate whether bladder dysfunction after bladder outlet obstruction (BOO) could be altered by treatment with cilostazol, a phosphodiesterase 3 inhibitor (PDE3i).

METHODS

Twelve-week-old female Sprague-Dawley rats were divided into 5 groups: groups 1 and 2, sham-operated rats and groups 3-5, BOO rats. Group 1 and 3 rats were given normal diet, group 2 and 5 rats were given high-dose PDE3i diet, and group 4 rats were given low-dose PDE3i diet. PDE3i was given within diet from the day of surgery. Four weeks after BOO, the bladder was excised and dissected into 4 longitudinal strips for isometric organ-bath assay. Contractile responses of bladder strips to electrical field stimulation (EFS), carbachol, and potassium chloride (KCl) were determined for each group.

RESULTS

BOO induced a significant increase in bladder weight in groups 3-5 compared with groups 1 and 2. PDE3i treatment did not affect bladder weight in sham or BOO rats. Contractile forces in response to EFS, carbachol, and KCl in group 3 were about 20%-40% of those in group 1. Contractile responses to EFS or KCl in PDE3i-treated BOO rats were not significantly different from those in group 3. Only high dose of PDE3i treatment in BOO rats caused a statistically significant increase in the response to carbachol compared with group 3.

CONCLUSION

PDE3i has a small but significant protective effect on the contractile dysfunction induced by a 4-week BOO in rats, although the increase in bladder mass was not altered. PDE3i could be a useful protection against contractile dysfunction of the obstructed bladder.

The effect of intravesical acetylsalicylic acid instillation on tissue prostaglandin levels after partial bladder outlet obstruction in rabbits

AIMS

To examine whether obstruction changes the expression of prostaglandins (PGs) in bladder, intravesical low-dose aspirin could be used as a new route of drug administration, this way of administration influences PGs' expression, and contractile function of the bladder is protected after treatment.

METHODS

Eighteen rabbits were divided into three groups. Sham-operated group (group 1) included 6 rabbits. Twelve rabbits were partially obstructed for 70 days. Six of these 12 rabbits not receiving any treatment constituted obstructed group (group 2). The remaining six rabbits received 2  mg/kg/day aspirin (group 3). One rabbit in each group was evaluated on 1st, 7th, 14th, 28th, 42nd, and 70th days following obstructive surgery. After scarification, the percentage of collagenous area and concentrations of PGE2 and PGF2-alpha were measured. Contractile responses to field stimulation (EFS), carbachol, and potassium chloride (KCl) were determined.

RESULTS

Wet tissue PGE2 and PGF2-alpha levels were higher in obstructed group than the other groups. Aspirin decreased the percentage of collagenous area in group 3 compared to the group 2, but this difference was not statistically significant. The strips from aspirin groups resulted in better contractile response to cholinergic stimulation with KCl, but this difference was not statistically significant between the obstructed and aspirin groups. Similarly, carbachol did not elicit significantly greater concentration-dependent contraction in strips from obstructed group compared to those from aspirin groups. Maximum responses to EFS were not significant in aspirin group compared to those from obstructed group.

CONCLUSIONS

Intravesical aspirin may have protective effect on partially obstructed bladder.

Is it possible to improve elderly male bladder function by having them drink more water? A randomized trial of effects of increased fluid intake/urine output on male lower urinary tract function

OBJECTIVES

Several animal studies have shown that bladder performance improves as a result of diuresis. Whether increased urine output also has beneficial effects on elderly male bladder function and lower urinary tract symptoms is unknown.

METHODS

We performed a randomized placebo-controlled trial of 141 men, 55 to 75 years of age, with moderate lower urinary tract symptoms. The experimental group drank 1.5 L of extra water daily. The control group consumed one tablespoon of placebo syrup daily. After 6 months, we evaluated bladder contractility, voided volumes, and the severity of lower urinary tract symptoms. The actual increase in water consumption was measured using the deuterium urine dilution method.

RESULTS

Water consumption in the intervention group increased by 359 mL (95% confidence interval [CI] 171 to 548) per 24 hours compared with the control group. At 6 months, no statistically significant effect was found in the maximal flow rate (0.9 mL/s, 95% CI -0.4 to 2.2) compared with placebo. A statistically significant effect was found for bladder pressure (20 cm H2O, 95% CI 6 to 34) and bladder wall stress (1.9 N/cm2, 95% CI 0.3 to 3.5). In addition, it showed that the experimental group had greater maximal (44 mL, 95% CI -1 to 90) and average (26 mL, 95% CI 1 to 51) voided volumes per urination. The subjective effect parameters improved in both groups, but no statistically significant differences were found between the two groups.

CONCLUSIONS

It seems possible to improve some aspects of male bladder function by drinking more water. However, the effects are too small to be clinically relevant.

Mechanism of action by which aspirin alleviates detrusor hyperactivity in rats

We examined the effect of aspirin on urodynamic parameters in normal and cyclophosphamide-induced cystitic rats and compared them in rats with or without sensory denervation. Cystometry was performed under urethane anesthesia; and volume threshold for micturition (VT), micturition frequency (MF), micturition pressure (MP), and micturition volume (MV) were determined. Cystitis was induced by pretreatment with cyclophosphamide and sensory denervation was performed by pretreating animals with a large dose of capsaicin. PGE(2) and 6-keto-PGF(1alpha) contents in the bladder were determined by ELISA. Sensory intact, cystitic rats showed decrement of VT and increment of MF. Aspirin increased VT and decreased MF in the cystitic condition. Both PGE(2) and 6-keto-PGF(1alpha) contents in the bladder were significantly increased in cystitic rats, but such increases were completely inhibited by aspirin. In sensory denervated rats, aspirin showed a marginal tendency of increment of VT. Cystitic rats showed overflow micturition in the sensory denervated condition, but VT was the same as that of normal rats. Furthermore, following capsaicin pretreatment, aspirin had no effect on the cystometrogram in cystitic rats. From these findings, it is concluded that suppression of sensory C-fiber via inhibition of PGs synthesis in the bladder is involved in the pharmacological action of aspirin in the detrusor hyperactivity.