Bladder mucin: a scanning electron microscopy study in experimental cystitis.

Scanning electron microscopy has been used to assess surface mucin changes following an induced Escherichia coli urinary tract infection in the rat bladder. The principal changes seen following bacterial challenge were bacterial adherence to the urothelium, swelling of epithelial folds, disruption of the mucin layer, and increased adherence of bacteria to the sub-surface epithelium. The bladder mucin before infection appeared as an even, whitish, viscous layer which covered epithelial cells and cell junctions. Bacteria appeared to become enmeshed in mucin strands after infection and this process may facilitate bacterial washout from the bladder. A recovery phase showed reversal of the scanning electron microscopy changes. These findings support other studies in suggesting that mucin may play a role in protecting the bladder from invading and adhering bacteria.