Abstract: Objective To explore a simple and efficient method for RNA extraction from vaginal secretion of patients with vulvovaginal candidiasis and to testify its feasibility. Methods Simulated samples of vaginal secretion were prepared by mixing the same concentration （1 × 106/L） of human HaCaT keratinocytes and reference Candida spores. RNA was extracted from the simulated sample by 5 methods, i.e. hot phenol, RNeasy kit, glass beads, grinding in liquid nitrogen + TRIzol, homogenate + TRIzol. The quality and quantity of extracted RNA were compared among these methods. The most efficient method was selected and applied to RNA extraction from clinical samples of patients with vulvovaginal candidiasis. Results RNA was extracted successfully from the standard mixture samples by all the 5 methods. The highest mass concentration of total RNA was extracted by hot phenol （0.6546 g/L）, followed by RNeasy kit （0.6010 g/L）, glass beads （0.2678 g/L）, homogenate + TRIzol （0.2284 g/L）, grinding in liquid nitrogen + TRIzol （0.2115 g/L）. Electrophoresis showed that the method of grinding in liquid nitrogen + TRIzol yielded the highest quality of RNA, and it was the only method which could extract RNA from both Candida spores and human cells in this study; moreover, the performance of this method in RNA extraction from clinical samples was verified by RT-PCR and fluorescent quantitative PCR. Conclusions TRIzol after grinding in liquid nitrogen is a simple and efficient method for RNA extraction from vaginal secretion, with the quality of extracted RNA adequate for following molecular biology research.

Key words: Vulvovaginal candidiasis, Vaginal secretion, RNA extraction