Effects of cystostomy on bladders function in young rats and its potential mechanism / 中华实用儿科临床杂志

ABSTRACT

Objective:To investigate the effects and mechanism of cystostomy on young rats′ bladders function.Methods:Eighty female SD rats were divided into cystostomy group, sham operation group (the two groups included day 1, 3, 5 after operation), control group(it included day 1, 3, 5 after operation) and medicine intervention group by using random number table, there were 8 rats in each group.Cystometry was conducted in cystostomy group (day 1, 3, and 5 postoperative subgroup), and voided interval (VI), voided volume (VV), postvoid residual urine (PVR), bladder capacity (BC), maximum bladder pressure (Pves.max), bladder threshold pressure (Pves.thr), and bladder compliance(△C) were recorded.The rats in sham operation and control groups voided freely in the condition of diuresis by intravenous infusion saline, and VV, PVR and BC were recorded.Bladders′ tissues were collected for HE staining and histopathological inflammation scores (HIS) after urodynamic investigations.In medicine intervention group, different doses of anisodamine were applied and the changes of VI, VV, PVR, BC, Pves.max and Pves.thr were observed.Results:The trend of VV, VI, BC and △C was upwards on days 1, 3, and 5 postcystostomy.Meanwhile, compared with control group [VV (1.408±0.033) mL, BC (1.411±0.032) mL], VV and BC on day 1 and 3 postcystostomy were less[VV (0.288±0.059) mL, (0.598±0.154) mL; BC (0.292±0.059) mL, (0.601±0.154) mL]. There were statistically significant differences ( P<0.05). However, VV, PVR and BC on day 5 postcystostomy were not different from that of control group(all P>0.05). HE staining demonstrated that the HIS of days 1 and 3 postcystostomy and day 1 post-sham operation were in severe inflammatory phase, with HIS >4 scores.Additionally, the inflammation on day 5 in cystostomy group and days 3-5 in sham operation group were mild (HIS<2 scores). The correlation test of BC and HIS was negative( r=-0.880, P<0.001). After the application of anisodamine on dose of 0.2 mg/kg, VI, VV and BC of the young rats on day 3 postcystostomy significantly increased, compared with those before intervention [(643.500±65.889) s, (1.073±0.110) mL, (1.076±0.110) mL vs.(367.938±77.697) s, (0.612±0.129) mL, (0.617±0.129) mL, all P<0.05], while PVR, Pves.max and Pves.thr did not significantly change compared with those before intervention. Conclusion:The recent abnormal changes of urodynamics postcystostomy were related to the traumatic acute bladder inflammation in the young rats.On day 5 after the surgery, the bladder function basically returned to normal with the regression of the acute bladder inflammation.Anisodamine at 0.2 mg/kg dose could effectively relieve the symptoms of overactive bladder postcystostomy.