Current knowledge on the role of microRNAs (miRNAs) in rabbit hemorrhagic disease
virus (RHDV) infection and the pathogenesis of rabbit hemorrhagic disease (RHD) is still limited.
RHDV replicates in the liver, causing hepatic necrosis and liver failure. MiRNAs are a class of short
RNA molecules, and their expression profiles vary over the course of diseases, both in the tissue
environment and in the bloodstream. This paper evaluates the expression of miRNAs in the liver
tissue (ocu-miR-122-5p, ocu-miR-155-5p, and ocu-miR-16b-5p) and serum (ocu-miR-122-5p) of rabbits
experimentally infected with RHDV. The expression levels of ocu-miR-122-5p, ocu-miR-155-5p,
and ocu-miR-16b-5p in liver tissue were determined using reverse transcription quantitative real-time
PCR (RT-qPCR), and the expression level of circulating ocu-miR-122-5p was established using
droplet digital PCR (ddPCR). The expression levels of ocu-miR-155-5p and ocu-miR-16b-5p were
significantly higher in the infected rabbits compared to the healthy rabbits (a fold-change of 5.8 and 2.5,
respectively). The expression of ocu-miR-122-5p was not significantly di�erent in the liver tissue from
the infected rabbits compared to the healthy rabbits (p = 0.990), while the absolute expression level of
the circulating ocu-miR-122-5p was significantly higher in the infected rabbits than in the healthy
rabbits (p < 0.0001). Furthermore, a functional analysis showed that ocu-miR-155-5p, ocu-miR-16b-5p,
and ocu-miR-122-5p can regulate the expression of genes involved in processes correlated with acute
liver failure (ALF) in rabbits. Search tool for the retrieval of interacting genes/proteins (STRING)
analysis showed that the potential target genes of the three selected miRNAs may interact with
each other in di�erent pathways. The results indicate the roles of these miRNAs in RHDV infection
and over the course of RHD and may reflect hepatic inflammation and impairment/dysfunction
in RHD
