Organotypic raft cultures for the in vitro evaluation of vaginal microbicidal agents - Microbicides have epithelium-specific effects when repeatedly added onto organotypic human keratinocyte cultures

Background and Objectives: The authors tested keratinocyte raft cultures to compare vaginal microbicides that could be used at high frequency to prevent transmission of sexually transmitted diseases but should have minimal effects on the vaginal epithelium. Study Design: Effects of previously described microbicides were analyzed on normal foreskin keratinocytes and human papillomavirus-immortalized cervical epithelial cells in raft cultures after hematoxylin-eosin staining and immunostainings for keratins, filaggrin, proliferating cell nuclear antigen and Ki67-antigen; toxicity toward feeder cells was monitored by quantifying interleukin-6 release. Results: Repeated addition of microbicides into the medium resulted in histologic alterations at concentrations predictable from cytotoxicity tests performed in submerged cultures and correlated with reduced interleukin-6 release. Normal interleukin-6 release was observed when histologic alterations were induced by microbicides applied onto the rafts. Conclusions: Adding microbicides onto raft cultures at effective virucidal concentrations shows harmful effects on epithelial tissues undetectable in submerged cultures.