Study on Differences of Inducible Nitric Oxide Synthase Gene Expression in Vesical Tissue after Intravesical Instillation of Three Different strains of BCG in Rat

Lee, Chun Gu; Kim, Jong Sung; Rim, Joung Sik; Chung, Hun Taeg

Abstract

Recently, BCG infection is known to induce nitric oxide(NO) production by macrophages through T cell mediated process and NO is known to be microbicidal and tumoricidal. There are several strains of BCG which are commercially available and vary in the number, pathogenicity, viability, and immunogenicity of organisms. Therefore, we wanted to know if there are any differences between three different strains of BCG(Pasteur, Connaught or Tice strain) on the induction of inducible NO synthase(iNOS) and the histological changes in vesical tissue after intravesical instillation of BCG in rats. Thirty two Sprauge-Dowley female rats were equally divided into 4 groups. In group 1, normal saline(0.85 ml/kg) was intravesically instilled one time. In group 2, 3, and 4, BCG of Pasteur strain(2mg/kg, normal saline 0.85ml/kg), Connaught strain(1.35mg/kg, normal saline 0.85ml/kg), Tice strain(0.21mg/kg, normal saline 0.85ml/kg) was instilled one time, respectively. The bladders were excised from each group on day 1, 3, 7, and 14 after BCG instillation. iNOS mRNA was not detected in the vesical tissues of control group, whereas it was strongly detected in group 2, 3, or 4. Also, iNOS mRNA was more strongly detected on day 1, 3, and 7 after intravesical BCG instillation than day 14 in the vesical tissues of group 2, 3, and 4. Histologic findings were well related with expression of iNOS mRNA. Our results indicate that intravesical BCG instillation of rat induces expression of iNOS mRNA in the vesical tissue accompanying the infiltration of inflammatory cells and suggest that all of the 3 strains of BCG including Pasteur, Connaught, and Tice are good at inducing expression of iNOS mRNA without significant differences between the strains.