Safety and feasibility of PVA formaldehyde absorbent sponge in noninvasive uterine fluid sampling and RNA sequencing.

Abstract

Uterine fluid RNA can be used as a test for endometrial receptivity, but there is still no noninvasive sampling method available. The polyvinyl alcohol (PVA) formaldehyde absorbent sponge, a medical bio-absorbent sponge with good water absorption and biophilic properties, can be used to develop a new noninvasive endometrial fluid sampler. This study aims to investigate the toxicity of PVA acetal absorbent sponges on endometrial epithelial cells and its effect on RNA sequencing (RNA-Seq). The experimental group using PVA formaldehyde absorbent sponge was prepared into 0.005%, 0.01% and 0.02% (w/v) suspension, and 0.01%, 0.05% and 0.1% (v/v) extract groups. The control group was only the complete culture medium. Nothing was added to the blank group. In vitro cytotoxicity assay was used to evaluate the survival rate of cells. Eight patients underwent in vitro fertilization treatment in the Reproductive Center of Xiangya Hospital, Central South University from November 2019 to January 2020. The uterine fluid of each patient was aspirated. The experimental group was inhaled with sterile PVA formaldehyde absorbent sponge and then immersed RNA-later solution. The control group was directly injected into the same amount of RNA-later solution. RNA-seq and data analysis was performed later. The vitro cytotoxicity assay showed that in suspension groups, there was no significance difference in cell survival between different co-culture time in 0.005% group (P=0.255). In the 0.01% and 0.02% group, there was no difference at each incubation time within 12 h (all P>0.05), but the cell survival rate was decreased at 24 h compared with 0 h (P<0.01, P<0.05). At the same co-culture time, the cell survival of the 3 concentration gradient groups were significantly lower than that of the control group (all P<0.05). The cell viability of the 0.005% concentration group was decreased less than 30% at 24 h, the 0.01% concentration group decreased more than 30% at 12 h, and the 0.02% concentration group was decreased more than 30% at 0 h. For extract groups, there was no significant difference in the survival rate within 6 h in 0.01% concentration group (all P>0.05), and the survival rate of 12 h and 24 h was lower than that of 0 h group (both P<0.01). In 0.05% group, there was no significant difference at each incubation time within 12 h (all P>0.05), but the survival rate at 24 h was lower than that at 0 h (P<0.05). There was no significant difference in survival rate at different culture time in 0.1% concentration group (P=0.082). At the same culture time, there was no significant difference in survival rate between 0.01% group and control group at 0, 3 and 24 h (all P>0.05). Except for 3 h, the survival rate of 0.05% and 0.1% groups was lower than that of control group (all P<0.05), and the decrease was all less than 30%. Uterine fluid RNA-seq showed that there was no significance difference in exonic rate, the detected genes and transcripts of RNA between the experiment groups and the control group (all P>0.05). The in vitro cytotoxic of PVA formaldehyde absorbent sponge on human endometrial epithelial cell meet the national standard of the cytotoxic of medical materials. Sampling the uterine fluid with this material does not affect the RNA-Seq results. PVA formaldehyde absorbent sponge is safe and feasible when appling to the noninvasive uterine fluid sampling and RNA sequencing.