RESUMO
This study was carried out to investigate pathogenesis of E. coli-induced cystitis by light and electron microscopy with immunocytochemistry. A group of ICR mice was intravesically given 0.3ml of E. coli DIE 174 lysate( 1000000000/ml). Another group was given E. coli lysate after acid solution(pH 4.5) washing for 30 minutes. The urinary bladders were observed at 2 hours and 24 hours after E.coli lysate irrigation. On light microscopy, submucosal edema, congestion, and perivascular neutrophilic infiltration occurred 2 hours after E. coli lysate irrigation. The congestion and acute inflammation were more pronounced 24 hours after. In cases of acid washing and E. coli lysate irrigation, mucosal acute inflammatory infiltration with edema and congestion was marked at early stage. Necrosis of transitional cells developed with time. On immunostain for E. coli, surface of transitional cells was stained 2 hours after E. coli lysate irrigation. At 24 hours after irrigation, intercellular spaces of transitional cells were stained. In cases of acid washing and E. coli lysate irrigation, entire mucosa was stained at early stage. Electron microscopically, transitional cells revealed increase of cytoplasmic processes, enlargement of cytoplasmic vesicles, and widening of intercellular spaces. There were large amounts of various shapes of lysosomes in neutrophils and monocytes infiltrated in the mucosa in acid washing groups. According to the above results, it is concluded that E. coli lysate may easily penetrate into the bladder mucosa and that the mucosal mucopolysaccharide plays as a barrier against bacterial invasion.