Cell-free DNA and IL-8 in follicular fluid of women within in vitro fertilization program

Abstract

The effectiveness of the in vitro fertilization (IVF) program does not exceed 40% and mostly depends on the oocytes quality, that is affected by the composition of the follicular fluid: a content of cytokines, growth factors, cell-free DNA (cfDNA), et al. Increased level of cfDNA in the follicular fluid is associated with indicators of ovarian reserve, as well as the effectiveness of stimulation in the IVF program. One possible reason for the high level of cfDNA can be considered an increase of IL-8 concentration. However, the role of IL-8 in regulation of reproductive processes is ambiguous and is presented in a few studies. In this connection, the aim of the study was to investigate a content of cfDNA and IL-8 in the follicular fluid of women, as well as the relationship between them, depending on the parameters of folliculo- and oogenesis, early embryogenesis and IVF outcomes. 62 women with infertility and undergoing IVF treatment have been enrolled in the study. We collected follicular fluid samples from dominant follicles using transvaginal ultrasound aspiration. The concentration of IL-8 in the follicular fluid was evaluated by flow fluorimetry. Measurement of cfDNA in the follicular fluid was performed by fluorimetric method. A negative correlation between IL-8 level in the follicular fluid and the number of received oocytes, as well as the quality of embryos was revealed. At the same time, a higher level of cfDNA was recorded in women with low blastocyst quality and non-developing pregnancy. Correlation analysis showed the absence of a significant direct relationship between IL-8 and cfDNA in the whole group. Moreover, in subgroups characterized by a higher IL-8 level, we found a weak negative correlation between cfDNA and IL-8 concentrations. The results suggest that enlarged level of cfDNA in the follicular fluid is not a consequence of IL-8 increase; the levels of IL-8 and cfDNA in the follicular fluid are two independent factors with multidirectional effects involved in various stages of reproductive process.