Evaluation of Effect of Minor Groove DNA- Binder on Trichomonas vaginalis in Vitro

Abstract

Trichomonas vaginalis is a common sexually transmitted parasite in human, primarily affecting urogenital tract. Infection has been associated with various inflammatory conditions, cervical erosion, cervical cancer, and infertility. Also adverse outcomes in pregnancy and increased susceptibility to acquisition and transmission of HIV have been reported. The present study was designed to in-vitro evaluate the therapeutic effect of a DNA minor groove binder drug ''Netropsin dihydrochloride'' on Trichomonas vaginalis. T. vaginalis trophozoites used in this study, were isolated from vaginal washout (G isolate) and urine sediment (U isolate). Also a previously known clinically resistant isolate ATCC 50138 (R isolate) was used. The three isolates used exhibit different growth pattern as well as different SDS-PAGE pattern. Netropsin was applied in doses ranging from 3.5 to 200µg/ml, the MIC was 12.5 µg/ml for G and U isolates and was 25 µg/ml for R isolate. Isolates showed affected motility after 6hours of exposure to netropsin with concentrations (50-200μg/ml) as revealed by inverted microscopy. Haemolytic assay showed zero% haemolysis by T. vaginalis treated with the MIC of netropsin for 24 hours. These observations were confirmed by SEM that revealed cytoskeletal affection and deformity of netropsin treated isolates. Cytotoxicity assay of netropsin treated isolates for 42 hours showed highly significant decrease in cell death% in comparison to the effect caused by untreated isolates. These results were confirmed by inverted microscopy that showed no cell line defect when using treated trophozoites. We concluded that netropsin is a promising drug in the treatment of T. vaginalis infection affecting its replication, virulence and viability with a mechanism of action overcoming the mechanism of T. vaginalis resistance.

Keywords: - Netropsin, T. vaginalis, SEM, cytotoxicity, DNA minor groove binder.