Urinary Excretion of Nitric Oxide Metabolite after Intravesical BCG Instillation in the Rat

Choi, Dong Gyu; Rim, Joung Sik; Chung, Hun Taeg

Abstract

Inducible nitric oxide(NO) is understood as a tumoricidal molecule. In animal study, urinary NO excretion after intravesical BCG instillation is recently known. In this study, the authors investigated the pattern of urinary nitrite (stable oxidizide form of nitric oxide) excretion according to the dosage of instilled BCG or number of BCG instillation. According to the dosage of instilled BCG(Pasteur strain :8.l5 x 1000000CFU/mg), 32 Sprauge-Dawley female rats were di-vided into 4 Groups(Group I: control, Group II: BCG1/l0X, Group III: BCGlX. Group IV :BCG10X). Also, each Group was subdivided into a one-time instillation subgroup(one time instillation at the first day) and a six-time instillation subgroup( weekly instillation for six weeks). The urinary nitrite in 24 hours' urine was measured quantitatively in each group by Titertek Multiscan MCC/340 ELISA Reader on an every other day basis after BCG instillation until decreased to control level. Intravesical BCG instillation of the rats led to significant urinary nitrite excretion in Group II (BCG 1/10X:one-time ;30+/-12, six-time ;52+/-6), Group III(BCG 1X,57+/-8, 62+/-2uM/L), Group IV (BCG 10X;65+/-2, 80+/-5uM/L) compared to Group I (control;22+/-4, 21+/-3uM/L) respectively( p<0.05). There was no statistical difference in the increment of urinary nitrite excretion between Group II, Group III and Group IV. The urinary nitrite excretion increased significantly in Group II and Group IV of six-time instillation subgroup compared to one-time instillation subgroup(p <0.05). BCG instillation resulted in significant excretion of urinary nitrite at the first day, which reached peak urinary level at the period of the 3rd to 9th day and the 11th day after instillation in one-time and six-time instillation subgroup respectively. The excretion also remained increased for 33 days and 44 days in two subgroups respectively. The preservation of the urine at -40'C for 4-weeks had no influence on the urinary nitrite concentration. The study demonstrates the pattern of urinary excretion according to the dosage of instilled BCG or number of instillations in addition to disclosing good effects of BCG on the excretion of urinary nitrite in rats. The following can be deduced from this study. Intravesical BCG instillation using only one tenth of the usual dose of which the BCG is used for treatment of superficial bladder tumor, and six-times resulted in effective excretion of urinary nitrite in rats.