Non-coding RNA profiles associated with equine osteoarthritis: a systematic review.

INTRODUCTION

Non-coding RNAs (ncRNAs) play a role in the pathogenesis of osteoarthritis (OA) by regulating gene expression related to inflammation, chondrocyte apoptosis, and extracellular matrix degradation. In horses, OA is a leading cause of lameness and poor performance, with no current treatments halting disease progression and no clear biomarker available. Although some studies have investigated expression profiles of ncRNAs in equine OA, there is a need to systematically review previous efforts and synthesize information to identify potential ncRNAs to target in future research.

METHODS

The search strategy was developed using the Population, Intervention, Comparison, Outcome, Studies (PICOS) framework. A comprehensive search of Scopus, ScienceDirect, CAB Abstracts, BIOSIS Previews, and Web of Science Core Collection identified studies written in English published through June 30, 2025, using comprehensive terms for ncRNAs in equine osteoarthritis. Eligible studies assessed differential ncRNAs expression profiles in natural and experimentally induced OA and control equids. Individual ncRNAs were categorized based on frequency across different studies: 1) identified in three or more samples across studies, 2) identified in two samples across studies or 3) unique to one sample in a single study. Differential expression (log2fold change) with p-values were extracted for each ncRNA and visualized using heatmaps.

RESULTS

Eight studies met the inclusion criteria, including four longitudinal and four case-control studies. Three investigated natural OA, four analyzed surgically induced OA and one employed a chemically induced OA model. Most studies utilized next-generation sequencing (NGS) to analyze ncRNAs, while two used quantitative polymerase chain reaction (qPCR). Three NGS studies included PCR validation. Multiple ncRNAs were identified, with microRNAs (miRNAs) being the most frequently found, followed by small nucleolar RNAs (snoRNAs). Among ncRNAs reported in at least three types of samples across independent studies, let-7a, miR-1307, miR-144, miR-744, and miR-98 were significantly upregulated, whereas miR-10a and miR-29b were significantly downregulated (p < 0.05).

DISCUSSION: Our findings of specific ncRNAs with shared expression profiles across multiple equine OA studies support their potential as OA biomarkers. Further research is necessary to determine the role of ncRNAs in OA development, such as contributions to cartilage degeneration, inflammation, and apoptosis, and to evaluate their potential as therapeutic targets.