Evaluation of circulating miRNAs in mares approaching parturition.

The research article explores how levels of circulating microRNAs (miRNAs) in pregnant mares change as they approach birth, in the hope of identifying potential biomarkers for predicting parturition (labor and delivery).

Objective of the Study

• The main objective of the study was to identify circulating miRNAs that change in concentration as mares approach parturition. The goal was to find potential biomarkers that could be used to predict the timing of parturition in these animals. These findings may have applications in equine breeding and veterinary medicine.

Methods Used in the Study

• The researchers collected plasma samples from pregnant Thoroughbred mares 30 days and 5-0 days prior to parturition. The reason for collecting samples this close to birth was to monitor changes in miRNA levels that occur as labor approaches.
• The collected samples were then subjected to small RNA sequencing (small RNA-seq) and reverse transcription quantitative PCR (RT-qPCR) to identify and quantify the miRNAs present.
• Progestin concentrations in the plasma were also measured using an enzyme-linked immunosorbent assay as a reference for hormonal changes leading up to parturition.

Key Observations and Results

• The small RNA-seq data indicated that the concentration of 18 miRNAs in the plasma was affected by the proximity of parturition.
• Specifically, two novel miRNAs and three known miRNAs (miR-361-3p, miR-483, and miR-99a) demonstrated significant changes in concentration when comparing samples taken 30 days before parturition with those collected 5-0 days before parturition.
• The study also found that the concentration of progestin, a hormone often associated with pregnancy and parturition, was higher 5-3 days prior to parturition than 30 days prior, and then decreased on the day of parturition. This hormonal observation provides a comparative reference to the changes observed in the miRNA levels.

Conclusions Drawn from the Results

• This study enriches the understanding of miRNA changes that occur in mares as they approach parturition. It also identifies and highlights particular miRNAs that demonstrate significant concentration changes close to parturition.
• The highlighted miRNAs could serve as potential biomarkers for predicting the timing of parturition in mares, which could have significant practical applications in equestrian breeding practices and veterinary medicine.